The Official *Saturn* Exploration Thread [Archive]

curiousuburb

2004-06-14, 22:22

Oh and btw: man, something BIG or some big things have definitely collided with poor old "Phoebes". :(

But the latest closeups of the crater have provided hints of water-ice. Craters can be good.

http://saturn.jpl.nasa.gov/multimedia/images/small-moons/images/PIA06075-br402.jpg (http://saturn.jpl.nasa.gov/cgibin/gs2.cgi?path=../multimedia/images/small-moons/images/PIA06075.jpg&type=image)
A Skyline View
June 14, 2004

Images like this one, showing bright wispy streaks thought to be ice revealed by subsidence of crater walls, are leading to the view that Phoebe is an ice-rich body overlain with a thin layer of dark material. Obvious down slope motion of material occurring along the walls of the major craters in this image is the cause for the bright streaks, which are over-exposed here. Significant slumping has occurred along the crater wall at top left.

The slumping of material might have occurred by a small projectile punching into the steep slope of the wall of a pre-existing larger crater. Another possibility is that the material collapsed when triggered by another impact elsewhere on Phoebe. Note that the bright, exposed areas of ice are not very uniform along the wall. Small craters are exposing bright material on the hummocky floor of the larger crater.

Elsewhere on this image, there are local areas of outcropping along the larger crater wall where denser, more resistant material is located. Whether these outcrops are large blocks being exhumed by landslides or actual 'bedrock' is not currently understood.

The crater on the left, with most of the bright streamers, is about 45 kilometers (28 miles) in diameter, front to back as viewed. The larger depression in which the crater sits is on the order of 100 kilometers (62 miles) across. The slopes from the rim down to the hummocky floor are approximately 20 kilometers (12 miles) long; many of the bright streamers on the crater wall are on the order of 10 kilometers (6 miles) long. A future project for Cassini image scientists will be to work out the chronology of slumping events in this scene.

This image was obtained at a phase, or Sun-Phoebe-spacecraft, angle of 78 degrees, and from a distance of 11,918 kilometers (7,407 miles). The image scale is approximately 70 meters (230 feet) per pixel. No enhancement was performed on this image.

Images collected during Cassini's close flyby of Saturn's moon, Phoebe, have yielded strong evidence that the tiny object may contain ice-rich material, overlain with a thin layer of darker material perhaps 300 to 500 meters (980 to 1,600 feet) thick.

The surface of Phoebe is also heavily potholed with large and small craters. Images reveal bright streaks in the ramparts of the largest craters, bright rays which emanate from smaller craters, and uninterrupted grooves across the face of the body.

"The imaging team is in hot debate at the moment on the interpretations of our findings," said Dr. Carolyn Porco, Cassini imaging team leader at the Space Science Institute in Boulder, Colo. "Based on our images, some of us are leaning towards the view that has been promoted recently, that Phoebe is probably ice-rich and may be an object originating in the outer solar system, more related to comets and Kuiper Belt objects than to asteroids."

In ascertaining Phoebe's origin, imaging scientists are noting important differences between the surface of Phoebe and that of rocky asteroids which have been seen at comparable resolution. "Asteroids seen up close, like Ida, Mathilde, and Eros, and the small martian satellites do not have the bright 'speckling' associated with the small craters that are seen on Phoebe," said Dr. Peter Thomas, an imaging team member from Cornell University, Ithaca, N.Y.

The landforms observed in the highest resolution images also contain clues to the internal structure of Phoebe. Dr. Alfred McEwen, an imaging team member from the University of Arizona, Tucson, said, "Phoebe is a world of dramatic landforms, with craters everywhere, landslides, and linear structures such as grooves, ridges, and chains of pits. These are clues to the internal properties of Phoebe, which we'll be looking at very closely in order to understand Phoebe's origin and evolution."

"I think these images are showing us an ancient remnant of the bodies that formed over four billion years ago in the outer reaches of the solar system," said Dr. Torrence Johnson, an imaging team member from NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Battered and beat-up as it is, it is still giving us clues to its origin and history."

Phoebe may be an icy interloper from the distant outer solar system which found itself captured by giant Saturn in its earliest, formative years. Final conclusions on Phoebe's origins await a combination of the results on Phoebe's surface structures, mass and composition gathered from all 11 instruments, which collected data during the flyby on June 11, 2004.

"This has been an impressive whirlwind flyby and it's only a curtain raiser on the events about to begin," said Porco.

Cassini arrives in orbit around Saturn on the evening of June 30, 2004 (July 1 Universal Time).

For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

Image Credit:
NASA/JPL/Space Science Institute

There are several other new images of Phoebe in the Image Gallery (http://saturn.jpl.nasa.gov/multimedia/images/latest/index.cfm)

Moogs

2004-06-14, 23:05

:eek: :wow:

curiousuburb

2004-06-14, 23:24

:eek: :wow:

If you think that crater photo is impressive, check out this one called Phoebe's Surprisehttp://saturn.jpl.nasa.gov/multimedia/images/small-moons/images/PIA06067-th100-75.jpg (http://saturn.jpl.nasa.gov/cgibin/gs2.cgi?path=../multimedia/images/small-moons/images/PIA06067.jpg&type=image)Phoebe's Surprise
June 13, 2004
Phoebe delivers on its promise to reveal new wonders to Cassini by showing probable evidence of an ice-rich body overlain with a thin layer of dark material. The sharply-defined crater at above center exhibits two or more layers of alternating bright and dark material. Imaging scientists on the Cassini mission have hypothesized that the layering might occur during the crater formation, when ejecta thrown out from the crater buries the pre-existing surface that was itself covered by a relatively thin, dark deposit over an icy mantle. The lower thin dark layer on the crater wall appears to define the base of the ejecta blanket. The ejecta blanket itself appears to be mantled by a more recent dark surface lag.

Moogs

2004-06-15, 19:54

http://www.computerpannen.com/cwm/cwm/cwm/eek2.gif

Mac+

2004-06-16, 00:51

So Phoebe could have been flying by from another solar system and Saturn pulled her into its orbit? What does this mean for our moon? How did we get that? :confused:

(... to be folowed up, of course, by: "Who are we?" & "Why are we here?") ;)

Moogs

2004-06-17, 00:07

Based on the composition of Moon rocks and other factors, one popular astronomical theory is that the Moon is a conglomeration of materials that resulted from a long-ago collision between the earth and a very large asteroid / comet / planetesimal body.

The way the rocks were formed and the amount of dust on the surface suggest the Moon was at one time mostly molten (which would could result from molten rock and ejecta being shot into space from a massive collision early in our planet's history). In fact the carbon dating indicates the Moon is [basically the same age as the similar rocks dated on earth].

HOM

2004-06-17, 00:26

In fact the carbon dating indicates the Moon is [basically the same age as the similar rocks dated on earth].
It's been a while since I took Geology, but don't you need organic material to do Carbon 14 dating?

:confused:

Moogs

2004-06-17, 09:59

Not sure how you're defining "organic", but much of the moon is convered with basalt rock like the kind found on earth, and evidently it can be dated. Good question though; I'm open to any different interpretations....

For reference:
ba-salt

n.
A hard, dense, dark volcanic rock composed chiefly of plagioclase, pyroxene, and olivine, and often having a glassy appearance.

Anything in that description fit your definition of "organic"? Maybe they were dated, just not with Carbon-14? Possible I misinterpretted something I read.

Mac+

2004-06-18, 02:13

Thanks Moogs - I never knew that was how our moon started! Freaky!

Were you an astronomy kid at school - where did you pick up this knowledge? I'm really just learning all this stuff from checking out this thread. :rolleyes: Oh well, better late than never! (I guess space and astronomy were never major points of fascination for me as a kid - my loss evidently. :( I'm really intrigued by the grandeur and enormity of this exploration and research into our solar system!)

Moogs

2004-06-18, 09:49

I was definitely an astronomy kid from the time I was in middle school, through high school. I've always been interested in this kind of thing. Probably I would have majored in Astronomy or Astro-physics if I was more mathematically inclined. Once you reach college, astronomy goes from neat pictures and their stories, to heavy-duty equations and number-crunching. Then if you're a God at that, you could try your hand at getting an advanced degree in some particular branch like Cosmology, but I imagine most people wash out of those programs.

All these guys we see on the Science channel (Tuesday nights are a very good source of Astronomy info) are pretty much God's in their chosen field I think. Astronomy and Cosmology are two of those odd profressions where, if you're not among the very best minds in the world, you don't get a job and end up teaching Atronomy 101 at the local university or Physics at the local high school. Very difficult profession to break into, probably because there's not a lot of funding to go around, so what does go around lands with the very cream of the crop, so to speak.

Some good books for you:

The Invisible Universe - by David Malin
(Most a photo book, but it's a really well-crafted collection of large format photos... you will be awe-struck).

Hubble Vision - by Peterson & Grant

Hubble Revisited - by Fischer & Duerbeck

Orbit - National Geographic
(Views of earth from space, with some good science tidbits for each).

The Illustrated Edition of A Brief History of Time - by Stephen Hawking
(Good visual primer for the basic tenets of cosmology and astro-physics)

Pale Blue Dot - by Carl Sagan
(Good primer on space exploration and other areas)

...and finally, a good link to get you to the real meaty stuff, if you're so inclined.

http://publishing.cambridge.org/stm/astronomy/

curiousuburb

2004-06-18, 21:17

Cassini Spacecraft Makes Final Course Change to Saturn

PASADENA, California (AP) _ The Cassini spacecraft successfully completed what is expected to be its last course-correction maneuver before reaching Saturn, NASA said Thursday.

The maneuver, performed Wednesday, adjusted the course Cassini will take to pass through a gap between two of Saturn's rings when the craft enters orbit on June 30.

"This should be our final approach maneuver. It's on to Saturn and orbit insertion," said Earl Maize, deputy program manager for the mission at NASA's Jet Propulsion Laboratory.

During the maneuver, Cassini's main engine burned for 38 seconds to slow the craft by about 8 mph (13 kph). Tracking data will be evaluated over several days to ensure that the path is correct.

"All indications show that everything is on target," the National Aeronautics and Space Administration statement said.

NASA TV has pre Orbit Insertion Press Conferences on the 29th and 30th, currently plans a post Orbit Insertion Press Conference on the 1st and already has a preliminary Cassini Science Briefing set for July 2nd with photos of the rings the closest they'll ever be during the 4 year mission.

www.Scaled.com 's Pioneering Private Spaceflight is scheduled for this coming Monday (http://www.space.com/missionlaunches/SS1_guide_040618.html).
Pilot (http://www.space.com/missionlaunches/spaceshipone__secretpilot_040618.html) choice still 'up in the air'. :D

And... it sounds like we might get bonus Bootid (http://www.space.com/spacewatch/bootid_meteors_040618.html) meteor showers Tuesday night and next weekend.

*prepares for kink in neck from looking up*

HOM

2004-06-19, 00:07

Not sure how you're defining "organic", but much of the moon is convered with basalt rock like the kind found on earth, and evidently it can be dated. Good question though; I'm open to any different interpretations....
Carbon 14 dating as far as I remember from Rocks For Jocks (Geology 101), requires dead organic material, be it plant or animal life. I might be wrong, but I'm too tired to google it right now and I don't really want to derail this thread further.

For reference:

Anything in that description fit your definition of "organic"? Maybe they were dated, just not with Carbon-14? Possible I misinterpretted something I read.
There a lots of ways of dating rocks. But they fall into two categories, direct and indirect dating. Direct, as its name implies, can be used to determine a specific date that the rock was formed or placed where it is. An example would be finding fossils of animals that we know the dates that they lived or an event like Mt. Vesuvius erupting for which we have a good time frame. The other type is based on our knowledge of how rocks form and which ones form first. There is also complex folding, but I'm not sure that would survive in a comet. We don't know how old the rock is, but we know which rock is older.

Regardless, if NASA thinks they have a good idea how old the rock is, I trust them. Shit, they put a man on the fucking moon, I bow to their knowledge of science.

curiousuburb

2004-06-19, 00:22

IIRC, some of the compositional analysis of Moon rocks that helped confirm historical origin yet Lunar uniqueness was the particular balance of other rare radioactive isotopes. Bombardment by cosmic rays on the Moon causes further changes (some of which allow us to confirm they're not recently of Earth), but the 'fingerprinting' is primarily isotopic concentrations. Martian meteorites are also distinct due to their own isotopic fingerprint.

As for the actual process by which the Moon was fractured off the early Earth, there are some NASA simulations of this done with varying degrees of particle dynamics and physics precision over the years. Some astronomy software (Starry Night, IIRC) also includes animations of this event in their multimedia gallery on CD/DVD.

709

2004-06-19, 00:32

Mac+

2004-06-19, 01:43

Thanks Moogs for the insight into the astronomy profession. I can totally understand and appreciate how demanding it must be to make it into this profession - your use of the word "God" in terms of being able to perform those mathematical calculations is not lost on me!

As for the books, I'll take a raincheck presently. There's a book by Laurel that was recommended in another thread and some letters of Reagan's that I want to read first! For now this thread will have to suffice as my first foray into this area. :)

Moogs

2004-06-19, 10:05

No problem. It's probably a wise idea to get your other books and magazine stacks out of the way before buying any Astronomy texts. I have found that once I start getting into that, I get more and more curious and start buying more books. Call it an addiction.

Anyway, I have two National Geographics, two Wired, two MIT Tech Reviews and a Scientific American in the Queue currently and I'm feeling like a slouch because of it. Until recently it was raining all the time around here... shoulda cleared the decks!

:o

curiousuburb

2004-06-21, 11:24

All this moon talk is very curious, because I've been led to believe the moon is either:

1) Older than the earth. How or when this postulate entered my brain I haven't a clue, but this is my first memory in regards to the moon.

2) A chunk split from the Earth in it's early stages of formation. 'Tiamet' comes to mind, though I don't remember exactly why. Something Sumerian I think...

Regardless, I love a big moon. Tycho is my favorite.

Space.com actually has some updates to the theory today, "Earth Hit by Neighbour in Making of Moon" (http://space.com/scienceastronomy/moon_formation_040621.html)
including revised suppositions as to where the colliding body came for.

709

2004-06-21, 11:30

Space.com actually has some updates to the theory today, "Earth Hit by Neighbour in Making of Moon" (http://space.com/scienceastronomy/moon_formation_040621.html)
including revised suppositions as to where the colliding body came for.Thanks! I'll check it out once their server stops getting slammed. :)

Moogs

2004-06-24, 10:47

curiousuburb

2004-06-25, 15:22

Have you guys seen the cover and insert map for this month's National Geographic? Holy crap... it's all about the Sun and its internal workings. Seriously awesome stuff for an Astronomy buff. I'm trying to figure out where to hang this poster. It's a closeup shot of two sun spots, taken from a special telescope. Just amazing and awe-inspiring.

If you like those, check out http://sohowww.nascom.nasa.gov/
The "Best of SOHO" page has some sweet solar shots.
Haven't seen the issue of NG in question, but the newest observer is TRACE (http://vestige.lmsal.com/TRACE/)
TRACE Picture of the day (click for full 1024x830): http://vestige.lmsal.com/TRACE/POD/T171_20010630_002625.gif (http://vestige.lmsal.com/TRACE/POD/images/T171_20010630_002625.jpg)
Caption and info here (http://vestige.lmsal.com/TRACE/POD/TRACEpod.html)

Moogs

2004-06-25, 15:25

Nnniiiiiice.

curiousuburb

2004-06-25, 15:35

Meanwhile, yesterday's Cassini briefing included data and imagery from Phoebe.

Confirmation of Water Ice proves origin as Kuiper Object from outer solar system not asteroid.

Confirmation of Carbon Dioxide, Ferrous Iron, and 'unidentified material' compound.

http://saturn.jpl.nasa.gov/multimedia/images/small-moons/images/PIA06400.jpg
Phoebe�s Mineral Distribution
June 23, 2004 . . . Full-Res: PIA06400 (http://photojournal.jpl.nasa.gov/catalog/PIA06400)

These set of images were created during the Phoebe flyby on June 11, 2004. The images show the location and distribution of water-ice, ferric iron, carbon dioxide and an unidentified material on the tiny moon of Saturn. The first image was taken with Cassini's narrow angle camera and is shown for comparison purposes only. The other images were taken by the visual and infrared mapping spectrometer onboard Cassini.

The infrared image of Phoebe obtained at a distance of about 16,000 km (10,000 miles) shows a large range of bright and dark features. The resolution of the image is about 4 km (2.5 miles). carbon dioxide on the surface of Phoebe is distributed globally, although it appears to be more prevalent in the darker regions of the satellite.

The existence of carbon dioxide strongly suggests that Phoebe did not originate in the asteroid belt, but rather in much colder regions of the Solar System such as the Kuiper Belt. The Kuiper Belt is a vast reservoir of small, primitive bodies beyond the orbit of Neptune. An unidentified substance also appears to be more abundant in the darker regions.

A map showing the distribution of water ice (blue), ferric iron (red), which is common in minerals on Earth and other planets, and the unidentified material (green). Water ice is associated with the brighter regions, while the other two materials are more abundant in the darker regions.

NASA TV (http://www.nasa.gov/multimedia/nasatv/MM_NTV_Breaking.html) plans the following coverage (all times EST)

June 29, Tuesday
12 p.m. - Cassini Saturn Orbit Insertion Press Conference - JPL (Interactive Media Briefing)
3 p.m. - 7 p.m. - Live Interviews on Cassini Saturn Orbit Insertion (Interactive Media Briefing)

June 30, Wednesday
12 p.m. - Cassini Saturn Orbit Insertion Status Press Conference - JPL (Interactive Media Briefing)
1 p.m. - NASA Honor Awards - HQ (Employee Event)
2 p.m. - News briefing: "17 countries, 7 years, 1 planet, The International Aspects of Cassini" - JPL (Interactive Media Briefing)
5 p.m. - 5:45 p.m. - "Ringside Chat" Press Conference - JPL (Interactive Media Briefing)
6 p.m. - 7 p.m. - Live Interviews on Cassini Mission - JPL (One-Way Media Interviews)
9:30 p.m. - 12:40 a.m. (July 1) - Live Commentary from Mission Control of Cassini-Huygens arrival at Saturn - JPL (Mission Coverage)

July

July 1, Thursday
1 a.m. - Cassini News Briefing: Post-Saturn arrival - JPL (Interactive Media Briefing)
7:45 a.m. - 11 a.m. - Live Commentary on Cassini's First Images (taken during orbit insertion) - JPL (Mission Coverage)
1 p.m. - News briefing: Cassini Saturn arrival first pictures - JPL (Interactive Media Briefing)
3 p.m. - 7 p.m. - Live Interviews on Cassini Mission - JPL (One-Way Media Interviews)

July 2, Friday
6 a.m. - 9 a.m. - Live Interviews with Dennis Boccippio on NASA's role in studying "Lightning and Lightning Safety Awareness" - MSFC (One-Way Media Interviews)
2 p.m - Cassini Preliminary Science Press Update - JPL (Interactive Media Briefing)

709

2004-06-25, 15:48

...but the newest observer is TRACE (http://vestige.lmsal.com/TRACE/)Holy crap. Those images are freakin' unbelievably cool. :eek:

curiousuburb

2004-06-25, 16:26

Holy crap. Those images are freakin' unbelievably cool. :eek:

Agreed.

And if this ain't the spitting image of an Creative Sun God....
http://vestige.lmsal.com/TRACE/POD/images/T171_000719_232925.gif

While the left menu link to movies leads primarily to grayscale versions,
the POD Archive pages (http://vestige.lmsal.com/TRACE/POD/TRACEpodarchive2.html) have some colour movies too.

Rain (http://vestige.lmsal.com/TRACE/POD/movies/rain.mov)

Solar Tornadoes (http://vestige.lmsal.com/TRACE/POD/movies/Tornadoes_000802.mov)

Filaments decay in magnetic arcades in Bastille Day Slinky (http://vestige.lmsal.com/TRACE/POD/movies/BastilleSlinky.mov)

Shit. Now I have to start a *Sun* Exploration Thread.
:\

Moogs

2004-06-25, 17:35

That figure actually looks kind of demonic to me... spooooky.

:cool:

autodata

2004-06-29, 10:57

It sounds nuts that they are passing this thing so close to the rings. I want to see the pictures.

curiousuburb

2004-06-29, 13:54

Today's Pre-Saturn Orbit Insertion Briefing was 'all systems go' for Cassini to get captured in 20 hours.

Navigation reports that after 7 years in space and 4.5 Billion kilometers travel, with the help of 4 gravity assists from Venus, Earth, and Jupiter and a few trajectory correction maneuvers, they expect SOI absolute accuracy to within 11 km, relative accuracy within 3 or 4 km. :wow:

http://saturn.jpl.nasa.gov/multimedia/images/mission/images/soi_earth-20040628.jpg
details here (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/mission/images/soi_earth-20040628.jpg&type=image)

The pass through the ring plane is well outside the densest rings, and the high gain antenna will rotate to face the direction of travel to act as a shield for the spacecraft in case of smaller particle impacts.

The maximum camera resolution at closest ring plane approach will be about 120 meters per pixel, while most ring particles are expected to be on the order of 10 meters or less in diameter, so seeing individual grains of ring material isn't going to happen. They'll be analyzing structure and potentially doing fluid dynamics to attempt to replicate patterns, and using the far ultraviolet and spectrographic systems to get compositional info.

First Titan encounter (of 43 during the mission) will take place July 2nd as well... so we get some ring data, then some Titan data quite early. Though of course, the delay from Saturn is about 1 hour 23 minutes and change.

This latest movie of Titan looks inviting.
http://saturn.jpl.nasa.gov/multimedia/videos/movies/PIA06080.gif

They've already measured interaction with Saturn's magnetosphere, and rotational audio (http://www.nasa.gov/mission_pages/cassini/media/cassini-062804.html).

curiousuburb

2004-06-30, 21:13

Live commentary for the Saturn Orbit Insertion is due to start at 1830 PST on NASA TV.

709

2004-06-30, 21:58

10 minutes to Ring Plane Crossing...... :)

I'm so excited!!!

curiousuburb

2004-06-30, 22:31

Cassini has survived the ascending Ring plane crossing.

Doppler confirms signal. SOI engine burn will start at 19:36 PST.

curiousuburb

2004-06-30, 22:37

Main Engine Burn!

709

2004-06-30, 22:41

'High-Five'-ing space nerds are cute. :) :) :)

Kickaha

2004-06-30, 22:48

Another 75 minutes... let's hope someone remembered to code up the endBurn() method... :D

curiousuburb

2004-07-01, 00:15

end of burn within 1 second of nominal predict.

Successful Orbit Insertion!

now for some photos...

drewprops

2004-07-01, 00:15

According to the guy on NASA TV right now they hit within one second of the predicts, lots of whooping and hollering right now. I think we still have one more pass through the rings, but here's hoping to 4+ years of great science from Saturn!

drewprops

2004-07-01, 00:16

jinx, you're it!

709

2004-07-01, 08:55

Raw images coming down...

709

2004-07-01, 09:58

Some very cool stuff! Can't wait until they get processed.

Moogs

2004-07-01, 10:14

Sweeeeet.

curiousuburb

2004-07-01, 10:24

Cassini's first image of the rings (unprocessed).
http://www.nasa.gov/images/content/61685main_SOI2-330.jpg
Image above: After becoming the first spacecraft to enter Saturn's orbit, Cassini sent back this image of a portion of the planet's rings. It was taken by the spacecraft's narrow angle camera and shows the dark, or unlit, side of the rings.

Press conference this morning might have processed versions of the first ring pics

curiousuburb

2004-07-01, 11:54

709

2004-07-01, 12:33

Is there a point when an orbiting piece of something-or-another becomes a 'moon' rather than just 'a big chunk'? Would it have something to do with the relation in size to the object it's orbiting? :confused:

Moogs

2004-07-01, 12:39

That is an amazing picture... I noticed the wake lines right away. I can't wait to see some of the more "telephoto" shots of the rings and their contents (assuming it ever gets that close).

curiousuburb

2004-07-01, 13:01

Bad news: this was the closest we'll ever get to the rings for the the next 4 years.
Good news: latest set of images about to be discussed on NASA TV briefing right now.

That image was 7km per pixel. They have one at 700m per pixel.

Most of these images are still pretty raw... processing will clean up the digital images to remove scan lines, enhance contrast, and composite multiple filters, including IR and UV imaging to add a lot more value to these images.

Briefing is starting.

Confirmation that both ring plan passes left the spacecraft untouched with no safe events.

autodata

2004-07-01, 13:18

I can't get over it:

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/SOI9.jpg

Kickaha

2004-07-01, 13:19

Well technically all the bits that make up the rings are moons... but their orbits are so overlapped and they're so close together and densely packed that they essentially become 'one thing'. Kind of like how your molecules are so close together that you're 'one thing'. ;)

If an object is in a discrete orbit of it's own, it's a moon. More precisely, a satellite, but we call them moons just to be confusing. Not to be further confused with The Moon, or Luna, since it's so bizarrely huge compared to other planetary/moon systems we know of that Terra/Luna are basically a binary planet. Pluto/Charon is the closest thing to what we have. Neat theories about how the relatively extreme tidal forces helped distribute heavy (ie, radioactive) elements in the Earth, and may have helped spur mutations and evolution...

But I digress.

709

2004-07-01, 13:35

Moogs

2004-07-01, 14:19

Has enough time passed since the rings formed (couple hundred million years ago according to the lady at the press conference), to know that these rings are not slowly coalescing into another very large moon... much like our moon may have coalesced?

curiousuburb

2004-07-01, 14:34

No definitive answer at the press conference to the future of the rings, but some of the gaps are shepherded by moons which may accrete some of the ring material over time, while some seem to be losing material into the rings over time.

Some fabulous new Wide angle images to match the F ring shot above, some Narrow angle zooms into the wake in the F ring, images of the magnetosphere, as well as audio and spectra from Cassini's 7 interactions with the Saturnian bowshock and magnetopause. Check the press release pages for them to post more.

curiousuburb

2004-07-01, 14:41

The big image of the Encke Gap with its inner scalloped edge (due to nearby moon travel) displays density waves that actually spiral in if you traced them around the plane, and may represent vertical oscillations off the ring plane (which ranges between 2 and 25m wide)

I think the briefing showed some animation from farther out which spotted moons in this gap, but it's not posted yet. Clearly their influence is impressive.

autodata

2004-07-01, 19:06

the ring plane (which ranges between 2 and 25m wide)
I don't think I'll ever get over how thin yet prominent the ring system is.

709

2004-07-01, 19:18

I don't think I'll ever get over how thin yet prominent the ring system is.No shit. I was conversing with the gf last week and our conversation led to Cassini/Saturn et al (yes, she's that cool, even after 7 years). Anyways, we were trying to figure out how thick the rings would be if our house was Saturn and our office was the outer ring edge. It's about 2k from front porch to front entrance, so with a little head calculating the rings came out to be roughly 1cm thick. :eek: :eek: :eek:

We both had a serious 'WTF?' moment. Unbelievable.

Moogs

2004-07-01, 19:47

Stunning stuff. I just switched my desktop to the "Approaching Saturn" shot from the JPL's May archive (the 17 million miles and closing one - natural color). Just awe-inspiring.

drewprops

2004-07-08, 00:39

What I want to know is: what that super "bright" methane(?) speck is that is showing up in all the latest photos????....really interesting!!!

Mac+

2004-07-08, 06:35

*nods/shakes head in appreciation and awe*

This is a cool thread!
Thanks for the links, images and info. Sincerely! :)

curiousuburb

2004-07-20, 00:57

Sorry for slacking in my updates... new term start.

ESA has a spiffy new "Where is Cassini Now (http://www.esa.int/images/WhereIsCassini4.swf)" Flash animation

Dark side detail of Dione
http://saturn.jpl.nasa.gov/multimedia/images/large-moons/images/PIA05418.jpg (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/large-moons/images/PIA05418.jpg&type=image)
The icy, cratered surface of Saturn's moon Dione shows more than just its sunlit side in these two processed versions of the same image.

The view at left, with only mild enhancement, shows a romantic crescent with large craters visible. The contrast in the version at the right has been greatly enhanced to show the side of Dione lit faintly by reflected light from Saturn. A similar phenomenon can be seen from Earth, when the Moon's dark side is visible due to "earthshine." The crater at the top of the image appears to have a sunlit central peak in the enhanced view - a common characteristic of craters on Dione as seen in Voyager images. Slight variations in brightness on the moon's dark side hint at the bright curved linear streaks, seen by Voyager. These streaks are thought to be deposits of water ice

Iapetus, the two-faced moon also gets a new photo
http://saturn.jpl.nasa.gov/multimedia/images/large-moons/images/PIA06100.jpg (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/large-moons/images/PIA06100.jpg&type=image)
The moon with the split personality, Iapetus, presents a puzzling appearance. One hemisphere of the moon is very dark, while the other is very bright. Whether the moon is being coated by foreign material or being resurfaced by material from within is not yet known.

Iapetus' diameter is about one third that of our own moon at 1,436 kilometers (892 miles). The latest image was taken in visible light with the Cassini spacecraft narrow angle camera on July 3, 2004, from a distance of 3 million kilometers (1.8 million miles) from Iapetus (pronounced eye-APP-eh-tuss).

The brightness variations in this image are not due to shadowing, they are real. The face of Iapetus visible was observed at a Sun-Iapetus-spacecraft, or phase, angle of about 10 degrees. The image scale is 18 kilometers (11 miles) per pixel. The image was magnified by a factor of two to aid visibility.

Titan fans are inside 100 days to the next flyby and dose of data (http://saturn.jpl.nasa.gov/multimedia/images/titan/index.cfm), then another 60 days of itching for Huygens Xmas-eve release.

Ring junkies might tip their hats to this rakish new view.
http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA05417.jpg (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/rings/images/PIA05417.jpg&type=image)
This dramatic view of Saturn�s rings draped by the shadow of Saturn, shows brightness variations that correspond to differences in the concentration of the ring particles as they orbit the planet.

The planet�s western limb is visible in the upper right corner. Three of Saturn�s moons can be seen here: Bright Enceladus (499 kilometers, or 310 miles across) is visible near lower right; Epimetheus (116 kilometers, or 72 miles across) appears at center left; and interior to the F ring, near the top of the image, is Prometheus (102 kilometers, or 63 miles across). The F ring, the outermost ring shown here, displays several knot-like features near the left side of the image.

The image was taken in visible light by the Cassini spacecraft wide angle camera on July 3, 2004, from a distance of 1.5 million kilometers (930,000 miles) from Saturn, at a Sun-Saturn-spacecraft, or phase, angle of about 108 degrees. This is the first processed wide angle camera image to be released since Cassini�s encounter with Jupiter in 2000. The image scale is 87 kilometers (54 miles) per pixel.

Messenger is due for launch to Mercury near the end of the month, so I'll have to start another thread. :\

curiousuburb

2004-08-17, 12:30

Cassini discovers two new moons around Saturn.

http://saturn.jpl.nasa.gov/multimedia/images/small-moons/images/PIA06106-br402.jpg (http://saturn.jpl.nasa.gov/news/press-releases-04/20040816-pr-a.cfm)
Cassini Uncovers New Moon
+Full Caption

With eyes sharper than any that have peered at Saturn before, the Cassini spacecraft has uncovered two moons, which may be the smallest bodies so far seen around the ringed planet.

The moons are approximately 3 kilometers (2 miles) and 4 kilometers (2.5 miles) across -- smaller than the city of Boulder, Colorado. The moons, located 194,000 kilometers (120,000 miles) and 211,000 kilometers (131,000 miles) from the planet's center, are between the orbits of two other saturnian moons, Mimas and Enceladus. They are provisionally named S/2004 S1 and S/2004 S2. One of them, S/2004 S1, may be an object spotted in a single image taken by NASA's Voyager spacecraft 23 years ago, called at that time S/1981 S14.

Naming conventions suggest lesser Greek God/desses will be candidates.

Mars Rover briefing tomorrow at 1pm EST will update Rover Health and crater rock analysis.

curiousuburb

2004-08-18, 15:11

NASA TV is about to show a press conference on Cassini's discovery of the 2 new Moons

stevegong

2004-08-21, 15:52

I believe Carbon 14 dating is not suitable for things that have been around this long. Carbon 14 can only be used to date things that are thousands of years old.

Potassium 40 dating however, iirc can be used to date rocks from over 4 billion years old.

curiousuburb

2004-09-04, 15:46

False colour image of the rings based on temperature.
http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA06425-br402.jpg (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/rings/images/PIA06425.jpg&type=image)
Saturn's Rings, Cold and Colder
September 2, 2004

The varying temperatures of Saturn's rings are depicted here in this false-color image from the Cassini spacecraft.

This image represents the most detailed look to date at the temperature of Saturn's rings. The image was made from data taken by Cassini's composite infrared spectrometer instrument.

Red represents temperatures of about 110 Kelvin (-261 degrees Fahrenheit), and blue 70 Kelvin (-333 degrees Fahrenheit). Green is equivalent to 90 Kelvin (-298 degrees Fahrenheit). Water freezes at 273 Kelvin (32 degrees Fahrenheit). The spatial resolution of the ring portion of the image is 200 kilometers (124 miles).

The data show that the opaque region of the rings, like the outer A ring (on the far right) and the middle B ring, are cooler, while more transparent sections, like the Cassini Division (in red just inside the A ring) or the inner C ring (shown in yellow and red), are relatively warmer.

The temperature data were taken on July 1, 2004, of the unlit side of the rings. In order to show the full breadth of the rings, a strip of temperature data was mapped onto a picture of the lit side of the rings taken with the Cassini narrow angle camera on May 11, 2004, a little over a month before Saturn orbit insertion. Cassini is too close to the planet and hence no pictures of the unlit side of the rings are available, so the temperature data were mapped onto a picture of the lit side of rings. Saturn is overexposed and pure white in this picture. Saturn's moon Enceladus is visible below the rings, toward the center. The original picture and caption are available at http://photojournal.jpl.nasa.gov/catalog/PIA05410.

For those with Red/Blue glasses, there's also a new composite of Phoebe in 3D
http://saturn.jpl.nasa.gov/multimedia/images/large-moons/images/PIA06426-th100.jpg (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/large-moons/images/PIA06426.jpg&type=image)

Also on tap this week, the GENESIS spacecraft is returning from its mission to sample the solar wind and is scheduled to drop it's sample return payload for airborne helicopter capture on Sep 8 (http://www.nasa.gov/mission_pages/genesis/main/index.html).

curiousuburb

2004-09-27, 19:09

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA06485-br402.jpg (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/rings/images/PIA06485.jpg&type=image)

Musical Rings
September 27, 2004
Full-Res: PIA06485 (http://photojournal.jpl.nasa.gov/catalog/PIA06485)

Looking something like the fibrous bow of a violin, Saturn's colorful rings sweep through this spectacular natural color view while two small moons look on.

From left, the moons visible here are Janus (181 kilometers, or 112 miles across) and Mimas (398 kilometers, or 247 miles across). Cassini's view in this image is from beneath the ring plane; the moons are on the far side of Saturn. Janus leads Mimas as the two moons orbit the planet.

Nearly the entire ring system can be seen in this view. The diaphanous C ring appears at the upper right, followed by the multi-hued B ring. Next, the famous Cassini division (4,800 kilometers, or 2,980 miles wide) separates the A and B rings. The outer edge of the B ring which forms the inner boundary of the Cassini division is maintained by a gravitational resonance with Mimas. Near the outer edge of the A ring are the Encke Gap (325 kilometers, or 202 miles wide) and the barely visible Keeler Gap (35 kilometers, or 22 miles wide). The faint, thread-like F ring is discernible just beyond the main rings.

The image was obtained with the Cassini spacecraft narrow angle camera on August 27, 2004, at a distance of 9.1 million kilometers (5.6 million miles) from Saturn. Images taken with red, green and blue filters were combined to create this color view. The moons have been enhanced in brightness to increase their visibility. The image scale is 54 kilometers (34 miles) per pixel.

Since my last update (sorry, busy), Cassini has discovered new Rings and Moons (http://saturn.jpl.nasa.gov/news/press-releases-04/20040909-pr-a.cfm) (QT video here (http://saturn.jpl.nasa.gov/multimedia/videos/movies/2-MoonsWEB-T1.mov))

We're also inside a month until the next major Titan flyby, in anticipation of Huygens release near Xmas.

BarracksSi

2004-09-27, 23:59

I just want to keep an eye on this thread!

The comment about the one moon looking like the Death Star was pretty good, too.

curiousuburb

2004-10-23, 13:35

Tune in for Titan on Tuesday

http://saturn.jpl.nasa.gov/multimedia/images/titan/images/PIA06090-br402-300.jpg (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/titan/images/PIA06090.jpg&type=image)

Tune in to Titan

On Tuesday, Oct. 26, Cassini will pass within 1,200 km (746 miles) of Saturn's giant moon Titan. The historic flyby will be the closest approach to Titan to date. NASA TV coverage begins Oct. 26 at 6:30 p.m. (PST).

autodata

2004-10-26, 00:34

http://www.fireantav.com/an/xanadu.jpg

curiousuburb

2004-10-26, 02:13

http://www.fireantav.com/an/xanadu.jpg
The caption should read:

Cassini Eyes Titan's Xanadu - October 25, 2004

This image taken on Oct. 24, 2004, reveals Titan's bright "continent-sized" terrain known as Xanadu. It was acquired with the narrow angle camera on Cassini's imaging science subsystem through a spectral filter centered at 938 nanometers, a wavelength region at which Titan's surface can be most easily detected. The surface is seen at a higher contrast than in previously released imaging science subsystem images due to a lower phase angle (Sun-Titan-Cassini angle), which minimizes scattering by the haze.

The image shows details about 10 times smaller than those seen from Earth. Surface materials with different brightness properties (or albedos) rather than topographic shading are highlighted. The image has been calibrated and slightly enhanced for contrast. It will be further processed to reduce atmospheric blurring and to optimize mapping of surface features. The origin and geography of Xanadu remain mysteries at this range. Bright features near the south pole (bottom) are clouds. On Oct. 26, Cassini will acquire images of features in the central-left portion of this image from a position about 100 times closer.

From here (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/titan/images/PIA06107.jpg&type=image) among a few new Titan shots released today

Expecting much better tomorrow night. Maybe even 100 times better. ;)
:D

curiousuburb

2004-10-26, 17:11

Coming up on 4 hours to the Titan flyby webcast (http://www.jpl.nasa.gov/webcast/cassini/).

(All times are Pacific time)

*
Titan Flyby
NASA TV Coverage
- October 26, 6:30 pm

Post-Flyby Briefing
NASA TV Coverage
- October 27, 9:00 am

Science Briefing
NASA TV Coverage
- October 28, 9:00 am

curiousuburb

2004-10-26, 21:43

Flyby success!

The webcast of data playback is starting.

curiousuburb

2004-10-26, 22:21

Looks like only 3 non-Apple notebooks in a room of 10+ glowing fruit logos. :D

curiousuburb

2004-10-27, 13:15

Some of the processed images from the flyby are up (http://saturn.jpl.nasa.gov/news/events/titana/index.cfm)

Radar data will help add a topographic picture tomorrow morning.

curiousuburb

2004-10-28, 13:21

Huygens Landing Site
http://www.nasa.gov/images/content/67907main_pia06136_detail.jpg (http://www.nasa.gov/mission_pages/cassini/multimedia/pia06136.html)
Shown here are two images of the expected landing site of Cassini's Huygens' probe (latitude 10.6 S, longitude 191 W). At right is a wide-angle image showing most of Titan's disc, with a scale of 10 kilometers (6.2 miles) per pixel. At left is a narrow-angle image of the landing site at a scale of 0.83 kilometers (.5 miles) per pixel (location shown by black box at right). North is tilted about 45 degrees from the top of both images. The surface has bright and dark markings with a streamlined pattern consistent with motion from a fluid, such as the atmosphere, moving from west to east (upper left to lower right). The image at left is 400 kilometers (249 miles) wide. Both images were taken by Cassini's imaging science subsystem through near-infrared filters.

Credit: NASA/JPL/Space Science Institute

+ High resolution (http://photojournal.jpl.nasa.gov/catalog/PIA06136)

+ View archive (http://www.nasa.gov/mission_pages/cassini/media/Cassini_Multimedia_Collection(Search_Agent)_archiv e_1.html)

False colour VIMS images of the same areas in Infrared
http://www.nasa.gov/images/content/67953main_pia06983_detail.jpg (http://www.nasa.gov/mission_pages/cassini/multimedia/pia06983.html)
This image taken by Cassini's visual and infrared mapping spectrometer clearly shows surface features on Titan. It is a composite of false-color images taken at three infrared wavelengths: 2 microns (blue); 2.7 microns (red); and 5 microns (green). A methane cloud can be seen at the south pole (bottom of image). This picture was obtained as Cassini flew by Titan at altitudes ranging from 100,000 to 140,000 kilometers (88,000 to 63,000 miles), less than two hours before the spacecraft's closest approach. The inset picture shows the landing site of Cassini's piggybacked Huygens probe.

Radar results this morning didn't cover the same area, but in the Northern hemisphere swath of 100km x 2000km they captured yesterday, the altimetry results showed less than a 50m variation in elevation... pretty flat surface they said.

More data should come out tomorrow. There was some fascinating chemistry stuff discussed this morning about the propensity for polymerization of certain hydrocarbons into other chains, sometimes 'metallic', sometimes 'white', and sometimes 'black' to certain instruments, but I would have liked to have heard more on how/why certain transformations occur.

Where in the atmosphere seems important, but Titan is somewhat unusual in that it passes in and out of Saturn's magnetosphere periodically in its orbit and is sometimes fully exposed to the solar wind, while at other times benefits from shielding against certain cosmic emissions and potentially mutagenic radiation.

Yesterday's results from scooping a sample of Titan's atmosphere.
http://www.nasa.gov/images/content/67933main_pia06980_detail.jpg (http://www.nasa.gov/mission_pages/cassini/multimedia/pia06980.html)
This graph shows data acquired by Cassini as it flew by Titan at an altitude of 1,200 kilometers (745 miles) on Oct. 26, 2004 - its closet approach yet to the hazy moon. The data is from Cassini's ion and neutral mass spectrometer, which detects charged and neutral particles in the atmosphere. The graph reveals a diversity of hydrocarbons in the high atmosphere above Titan, including benzene and diacetylene.

Still more questions than answers, but it's sure fascinating.

BarracksSi

2004-10-29, 19:00

curiousuburb, thanks for the distilled updates. This is good stuff.

curiousuburb

2004-11-05, 18:02

Planetary Society/ESA Announce: Titan Art Contest (http://www.esa.int/esaCP/SEMZDG0A90E_index_0.html)

Best image(s) by Nov 28th win a trip to Germany to watch Huygens descent live at ESA control.

How to enter

Create an artwork representing what you imagine Titan looks like underneath its haze, based on your perspective on Huygens' journey. Are you viewing the moon from the air after Huygens breaks through the cloud or on the surface after the craft has parachuted to a landing? Did Huygens land on solid ground or is she floating in an ethane sea? Send us your vision of what lies beneath the veil when you imagine Titan.

Once you have finished your artwork you can enter the contest online. You do not need to mail your work, just create it on the computer, take a digital photo or scan your artwork. However, if you are not able to enter the contest digitally, you can also mail it to us. *
*
Contest questions and answers
*
Who can enter?

Anyone aged 10 and above may enter either in the youth section (aged 10-17) or the adult section (18 and over).

What kind of art can I create?

You can use any medium to create your artwork and then send us a digital image through the online entry form. You can also mail your art to us but please note that it should be no larger than 2.5 x 28 x 43 cm (1 x 11 x 17 inches) and that we cannot return artwork.

When does the contest end?

28 November 2004 at 23:59 Pacific time

What can I win?

The Grand Prize is a trip to Darmstadt, Germany to be on site at ESA's Operations Centre for the descent of the Huygens probe. There are also four first prizes (two for both sections) and up to 20 second prizes. The Grand Prize Winner will be chosen from among the first prize winners.

All the winning artwork will be displayed at ESA's European Space Operations Centre (ESOC) during the Huygens mission to Titan and winners will all receive a Planetary Society prize package. This contains: one year's free Planetary Society membership; a Certificate of Honour; a Cassini-Huygens Mission Patch; an ESA poster, pin and keychain; and a 'Nine Planets' lithograph set.

In addition, two special prizes (one in each section) will be awarded for the artwork that most closely resembles any part of the image of the Titan panoramic landscape taken by the Huygens probe during its final descent. These awards, a framed and autographed Huygens photo of the Titan landscape, will be made within 30 days of the return of the actual Titan image data.

Mailing address for postal entries
Huygens Art Contest
The Planetary Society
65 N Catalina Ave.
Pasadena
CA 91106
USA

Get your paints and pixels going, ladies and gentlemen of artistic bent.
It is remotely possible you might even get a bit of Titan named after you.

curiousuburb

2004-11-30, 23:06

Inspiring true-colour Cassini picture of the week... Mimas against the rings shadow.

http://saturn.jpl.nasa.gov/multimedia/images/large-moons/images/PIA06142.jpg (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/large-moons/images/PIA06142.jpg&type=image)

Nature's Canvas
November 29, 2004
Full-Res: PIA06142 (http://photojournal.jpl.nasa.gov/catalog/PIA06142)

In a splendid portrait created by light and gravity, Saturn's lonely moon Mimas is seen against the cool, blue-streaked backdrop of Saturn's northern hemisphere. Delicate shadows cast by the rings arc gracefully across the planet, fading into darkness on Saturn's night side.

The part of the atmosphere seen here appears darker and more bluish than the warm brown and gold hues seen in Cassini images of the southern hemisphere, due to preferential scattering of blue wavelengths by the cloud-free upper atmosphere.

The bright blue swath near Mimas (398 kilometers, or 247 miles across) is created by sunlight passing through the Cassini division (4,800 kilometers, or 2,980 miles wide). The rightmost part of this distinctive feature is slightly overexposed and therefore bright white in this image. Shadows of several thin ringlets within the division can be seen here as well. The dark band that stretches across the center of the image is the shadow of Saturn's B ring, the densest of the main rings. Part of the actual Cassini division appears at the bottom, along with the A ring and the narrow, outer F ring. The A ring is transparent enough that, from this viewing angle, the atmosphere and threadlike shadows cast by the inner C ring are visible through it.

Images taken with red, green and blue filters were combined to create this color view. The images were obtained with the Cassini spacecraft narrow angle camera on Nov. 7, 2004, at a distance of 3.7 million kilometers (2.3 million miles) from Saturn. The image scale is 22 kilometers (14 miles) per pixel.

curiousuburb

2004-12-11, 15:54

Some fabulous new photos have been parked on the Cassini Gallery pages (http://saturn.jpl.nasa.gov/multimedia/images/latest/index.cfm) in the past week, including Iapetus and more Ring shots and more as we approach the Titan-B flyby 12/13 and Dione closest approach 12/15 on our way to the biggest event of the mission so far.

I'll be airborne for some of this on approach to the UK (explained in another thread), but will try to update again before Huygens probe release in two weeks.

Choice among the uploads are these two showing Prometheus mooching material and potentially causing more wake disturbances and perturbations in the F ring, and a quicktime movie called "Tilt and Whirl".

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA06143.jpg
Thieving Moon
December 3, 2004 _ Full-Res: PIA06143 (http://photojournal.jpl.nasa.gov/catalog/PIA06143)

As it completed its first orbit of Saturn, Cassini zoomed in on the rings to catch this wondrous view of the shepherd moon Prometheus (102 kilometers, or 63 miles across) working its influence on the multi-stranded and kinked F ring.

The F ring resolves into five separate strands in this closeup view. Potato-shaped Prometheus is seen here, connected to the ringlets by a faint strand of material. Imaging scientists are not sure exactly how Prometheus is interacting with the F ring here, but they have speculated that the moon might be gravitationally pulling material away from the ring. The ringlets are disturbed in several other places. In some, discontinuities or "kinks" in the ringlets are seen; in others, gaps in the diffuse inner strands are seen. All these features appear to be due to the influence of Prometheus.

The image was taken in visible light with the narrow angle camera on Oct. 29, 2004, at a distance of about 782,000 kilometers (486,000 miles) from Prometheus and at a Sun-Prometheus-spacecraft, or phase, angle of 147 degrees. The image scale is 4.7 kilometers (2.9 miles) per pixel. The image has been magnified by a factor of two, and contrast was enhanced, to aid visibility.

http://saturn.jpl.nasa.gov/multimedia/videos/latest/thumb/PIA06144.jpg
Tilt and Whirl
December 3, 2004 _ Full-Res: PIA06144 (http://photojournal.jpl.nasa.gov/catalog/PIA06144) _ QuickTime (1.7 MB) (http://saturn.jpl.nasa.gov/multimedia/videos/latest/movies/PIA06144_half_movie.mov)

Zigzagging kinks and knots dance around Saturn in this movie of the F ring from Cassini. From a great distance, as during Cassini's initial approach to Saturn in mid-2004, the F ring appears as a faint, knotted strand of material at the outer fringe of Saturn's immense ring system. From this close vantage point, just after the spacecraft rounded the planet to begin its second orbit, the F ring resolves into several ringlets with a bright central core. The core of the F ring is about 50 kilometers (31 miles) wide and is located at a distance of approximately 80,100 kilometers (49,800 miles) from Saturn's cloud tops.

Scientists have only a rough idea of the lifetime of features like knots and clumps in Saturn's rings, and studies of images, such as those comprising this movie, will help them piece together this story.

The view here is from Cassini's southern vantage point, below the ringplane. During the course of the movie sequence, Cassini was headed on a trajectory that took the spacecraft away from the planet and farther south, so that the rings appear to tilt farther upward. To help visualize this, note that the top portion of the F ring is closer to the spacecraft, while the bottom portion is farther away and curves around the far side of Saturn.

The movie consists of 44 frames taken three minutes apart, so that the span of time represented in the sequence is almost exactly two hours, or about one-eight of a Saturn rotation. The images that comprise this movie sequence were taken in visible light with the Cassini spacecraft narrow angle camera on Oct. 28, 2004, and at distances ranging from approximately 516,000 kilometers (321,000 miles) to 562,000 kilometers (349,000 miles). No enhancement was performed on the images.

Get ready for mainstream media coverage to ramp up in advance of the 12/26 Huygens release.

curiousuburb

2004-12-27, 10:36

Huygens released on time and on target... Titan here we come... landing Jan 14th.

True colour Cassini picture of the week... Saturn, Titan, and (hard to spot) Mimas.

http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA06164-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1246)
Cassini's Holiday Greetings
December 24, 2004 Full-Res: PIA06164 (http://photojournal.jpl.nasa.gov/catalog/PIA06164)

From its station nearly 1.2 billion kilometers (746 million miles) from Earth, the stalwart Cassini spacecraft sends holiday greetings to Earth with this lovely color portrait of Saturn and two of its moons.

The 2004 holiday season marks the close of a miraculous year that saw the end of Cassini's long journey across the solar system and the beginning of its adventures in orbit around Saturn. In a triumph of human achievement, the Cassini mission has already returned thousands of images and has begun to uncover the mysteries of the Saturn system. This color portrait serves as reminder of the Saturnian places we have already seen and the promise of future discovery at Titan when the European Space Agency's Huygens probe arrives at Titan on Jan. 14, 2005.

The image shows the majestic ringed planet, with bands of colorful clouds in its southern hemisphere. The planet's northern extremes have a cool bluish hue, due to scattering of blue wavelengths of sunlight by the cloud-free upper atmosphere there. Long shadows of the icy rings stretch across the north.

A grayish, oval-shaped storm is visible in Saturn's southern hemisphere and is easily 475 kilometers (295 miles) across - the size of some hurricanes on Earth.

Titan (5,150 kilometers, or 3,200 miles across) is visible near lower right with its thick, orange-colored atmosphere, and faint Mimas (398 kilometers, or 247 miles across) appears just right of the rings' outer edge.

Images taken in the red, green and blue filters with the Cassini spacecraft wide angle camera on Dec. 14, 2004, were combined to create this color view at a distance of approximately 719,000 kilometers (447,000 miles) from Saturn. The image scale is 43 kilometers (27 miles) per pixel.

curiousuburb

2005-01-05, 10:34

And in news from that other groovy NASA planetary exploration mission about to celebrate a year exploring Mars (http://mars.jpl.nasa.gov) when most predicted a 90-day warranty or failure... Videos and Flash features marking the year are up at the link above... the official celebration to come later this month.

Fragmented Shield
http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20050103a/1N157575101ILF40B0P1985L0M1-B336R1_br.jpg (http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20050103a/1N157575101ILF40B0P1985L0M1-B336R1.jpg)

Heat Shield Flank

This image from NASA's Mars Exploration Rover Opportunity shows a portion of the heat shield that the spacecraft jettisoned shortly before landing. This flank piece broke off from the main piece of the heat shield upon impact. The crater created by the impact of the heat shield can be seen in the upper right of the image. Rover tracks appear across the top of the image. Opportunity took this image with its navigation camera during the rover's 331st martian day, or sol (Dec. 28, 2005).

From several new images approaching the Heat Shield here (http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20050103a.html)

See also the MER team's picks for the Rover's Top 10 Colour images of 2004 (http://marsrovers.jpl.nasa.gov/10topImages/01.html)

Moogs

2005-01-06, 01:18

Tangent: did you guys know there is a NASA TV station on DirecTV? Not always the most riveting stuff (dead air time with shots of the mission control consoles for example), but pretty cool anyway. Channel was in the 300s I think. Check it out if you have DTV.

curiousuburb

2005-01-12, 00:41

Huygens is Go for Titan Entry Jan 14th...

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA06172-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA06172-br500.jpg)

Go Huygens!
January 11, 2005 Full-Res: PIA06172 (http://photojournal.jpl.nasa.gov/catalog/PIA06172)

This map illustrates the planned imaging coverage for the Descent Imager/Spectral Radiometer, onboard the European Space Agency's Huygens probe during the probe's descent toward Titan's surface on Jan. 14, 2005. The Descent Imager/Spectral Radiometer is one of two NASA instruments on the probe.

The colored lines delineate regions that will be imaged at different resolutions as the probe descends. On each map, the site where Huygens is predicted to land is marked with a yellow dot. This area is in a boundary between dark and bright regions.

This map was made from the images taken by the Cassini spacecraft cameras on Oct. 26, 2004, at image scales of 4 to 6 kilometers (2.5 to 3.7 miles) per pixel. The images were obtained using a narrow band filter centered at 938 nanometers - a near-infrared wavelength (invisible to the human eye) at which light can penetrate Titan's atmosphere to reach the surface and return through the atmosphere to be detected by the camera. The images have been processed to enhance surface details. Only brightness variations on Titan's surface are seen; the illumination is such that there is no shading due to topographic variations.

For about two hours, the probe will fall by parachute from an altitude of 160 kilometers (99 miles) to Titan's surface. During the descent the camera on the probe and five other science instruments will send data about the moon's atmosphere and surface back to the Cassini spacecraft for relay to Earth. The Descent Imager/Spectral Radiometer will take pictures as the probe slowly spins, and some these will be made into panoramic views of Titan's surface.

This map (PIA06172) shows the expected coverage by the Descent Imager/Spectral Radiometer side-looking imager and two downward-looking imagers - one providing medium-resolution and the other high-resolution coverage. The planned coverage by the medium- and high-resolution imagers is the subject of the second map (PIA06173).

NASA TV/webcast will carry ESA TV during the Titan events.
Check the TV schedule for full details (all times listed are in Eastern Time).

January 13, Thursday
10:55 a.m. - 11:30 a.m. - Huygens Final Status (http://www.esa.int/SPECIALS/Cassini-Huygens/index.html) News Conference From ESA

January 14, Friday
3 a.m. - Live Coverage Begins
11:15 a.m. - 12:15 p.m. - Huygens Probe News Briefing (will confirm if data is being received)
5 p.m. - 6 p.m. - ESA Commentary and "Presentation of First Triplet Image of/data from Titan"

January 15, Saturday
5 a.m. - 6 a.m. - ESA News Briefing "Early Look at Science Results"

I know what I'll be watching this weekend.

Moogs

2005-01-12, 01:20

Huygens is Go for Titan Entry Jan 14th...

Thanks for keeping this in the fore-front of our minds. Truthfully much more important than anything Apple does.

I guess I should just stay up early Friday. I have to be at work very early to leave for a team road trip anyway. Might as well just sleep early on in the car anyway.

drewprops

2005-01-13, 23:57

If anyone wants to tune over to NASA-TV you can listen in to the pre-descent news conference for the Huygens probe, which will hit Titan's surface in the next 8 hours. I love it when NASA-TV has exciting mission-oriented programming!

curiousuburb

2005-01-14, 10:35

Huygens has landed on Titan... Data Playback to follow.

curiousuburb

2005-01-14, 11:49

"A Fantastic Success... We are the first visitors to the surface of Titan."
- ESA chief at this morning's Huygens (First Science Data Recieved) Briefing

[that we know of]

"Huygens continued to send data, received here on Earth through ground stations, after Cassini had to end scheduled high-data rate reception to turn and relay science to us."

"All spacecraft housekeeping data in the stream looks normal."

I may be misinterpreting this early (more coffee on the way), but I took this to mean that the batteries lasted longer than expected, and effectively that we have more data from Huygens on the surface of Titan than we had bandwidth for.

Cassini was always due to have limited data take due to orbit planning, but the fact that Earth stations picked up the Huygens-to-Cassini carrier signal and our final limitation on new data is/was the shortage of "big ears" more than a billion miles away.

"Last spacecraft Carrier was at 1555GMT from a station in Australia... Radio telescopes around the world are being requested to try and track longer to extend the scientific doppler work and see how long Huygens survives"
- Huygens Principal Investigator Dr. Jean-Pierre Lebreton

The first "Actual Science Results" briefing won't start for a few hours as they decompress the datastream and collect enough info to feed the world's media.

Landing on other worlds is cool.

curiousuburb

2005-01-14, 12:05

perhaps even more impressive... of the entire scheduled high-data rate relay,
not one packet was lost from B channel (redundant A channel is not happy, yet)

damn

meaningless

2005-01-14, 12:31

I am impressed that Huygens was still transmitting after Cassini dropped below Titan's horizon AND the fact that our ground stations were able to detect those continued signels! I don't know if that is still the case or not but hopefully details will follow at the next press briefing.

Landing on other planets / moons IS cool.

I cannot wait to see what images Huygens was able to snap. Show me them methane seas, damnit! :)

I remembered listening to NPR (maybe?) a few months ago. Someone theorized that if such seas exists on Titan, the wave action would be surreal. It would be higher than normal earth waves and move much slowly. That would be a sight to see.

I wonder if the pictures will be in color? Titan's orange skies - confirmed?

BarracksSi

2005-01-14, 13:23

Any aliens?

;)

This is cool as shit, really. I'd like to see what National Geographic puts together in another month or two.

Thanks again for the updates, curiousuburb.

curiousuburb

2005-01-14, 15:08

First images back are from the Descent Imager... they have 350 images...
showed two from more than 10km up... below the haze looking down.

claiming to see drainage features... pics aren't posted yet, and aren't processed to clean noise either...

should get clearer later

thegelding

2005-01-14, 15:31

land and sea??

g

http://msnbcmedia.msn.com/j/msnbc/Components/Photos/050114/050114_titan2_hlg_12p.hlarge.jpg

Powerdoc

2005-01-14, 16:10

According to the head admin of Huygens, decoding such image is a long task.
Nobody on earth have an idea about the appearance of the surface of Titan.

curiousuburb

2005-01-14, 18:29

According to the head admin of Huygens, decoding such image is a long task.
Nobody on earth have an idea about the appearance of the surface of Titan.

http://www.esa.int/images/landing01_L2.jpg (http://www.esa.int/SPECIALS/Cassini-Huygens/SEMBQO71Y3E_0.html)

This raw image was returned by the ESA Huygens DISR camera after the probe descended through the atmosphere of Titan. It shows the surface of Titan with ice blocks strewn around. The size and distance of the blocks will be determined when the image is properly processed.

curiousuburb

2005-01-14, 21:51

Total size of the effective Huygens Data Set during primary relay via Cassini: 4h32m (end by Horizon)

- beyond expected battery life/'warranty' period

Data decompression & replay scheduled for 8 replay sessions to ensure error free decode.

Preliminary analysis suggest no packet loss on Channel B, good science,
primarily atmospheric composition, charge, pressure, etc at one second inhalations on the way to the surface.

Extended carrier wave detection from Earth Radio Telescopes as bonus doppler science not finalized.

More info at the 1/15 ESA Briefing

curiousuburb

2005-01-15, 12:54

ESA brings you the microphone science on the way down through Titan's atmosphere...

Sounds of Titan (http://www.esa.int/esaCP/SEM85Q71Y3E_index_0.html)

Titan Winds.mp3 (http://esamultimedia.esa.int/images/huygens_alien_winds_descent.mp3)

Radar Descent.mp3 (http://esamultimedia.esa.int/images/huygens_alien_winds_descent_radar.mp3)

New composite image surface pictures in a panorama

http://www.nasa.gov/images/content/105764main_pia07230-330.jpg (http://www.nasa.gov/mission_pages/cassini/multimedia/pia07230.html)

This composite was produced from images returned yesterday, January 14, 2005, by the European Space Agency's Huygens probe during its successful descent to land on Titan. It shows a full 360-degree view around Huygens. The left-hand side, behind Huygens, shows a boundary between light and dark areas. The white streaks seen near this boundary could be ground 'fog,' as they were not immediately visible from higher altitudes.

As the probe descended, it drifted over a plateau (center of image) and was heading towards its landing site in a dark area (right). From the drift of the probe, the wind speed has been estimated at around 6-7 kilometers (about 4 miles) per hour.

These images were taken from an altitude of about 8 kilometers ( about 5 miles) with a resolution of about 20 meters (about 65 feet) per pixel. The images were taken by the Descent Imager/Spectral Radiometer, one of two NASA instruments on the probe.

and the processed, colour version of the surface of Titan seen yesterday.

http://www.nasa.gov/images/content/105768main_pia07232-516.jpg (http://www.nasa.gov/mission_pages/cassini/multimedia/pia07232.html)

This image was returned yesterday, January 14, 2005, by the European Space Agency's Huygens probe during its successful descent to land on Titan. This is the colored view, following processing to add reflection spectra data, and gives a better indication of the actual color of the surface.

Initially thought to be rocks or ice blocks, they are more pebble-sized. The two rock-like objects just below the middle of the image are about 15 centimeters (about 6 inches) (left) and 4 centimeters (about 1.5 inches) (center) across respectively, at a distance of about 85 centimeters (about 33 inches) from Huygens. The surface is darker than originally expected, consisting of a mixture of water and hydrocarbon ice. There is also evidence of erosion at the base of these objects, indicating possible fluvial activity.

The image was taken with the Descent Imager/Spectral Radiometer, one of two NASA instruments on the probe.

Aside from the admission of a human error in failing to enable Cassini capture of the A data channel, it looks and sounds like a great success so far.

Kickaha

2005-01-15, 13:28

Did anyone else listen to the radar descent MP3 and think "OMG, it's Defender!"?

curiousuburb

2005-01-16, 19:59

I'm sure it's already being worked into some Eurotechno

drewprops

2005-01-20, 00:48

Has anyone seen the image of where the lander landed? Did you see the strange geometric features above that area? It looks like Darth Vader playing soccer!! Check this out:

http://homepage.mac.com/drewprops/applenova/darthstructure.jpg

murbot

2005-01-20, 18:05

http://www.esa.int/images/landing01_L2.jpg (http://www.esa.int/SPECIALS/Cassini-Huygens/SEMBQO71Y3E_0.html)

Bah. That's only one frame.

http://homepage.mac.com/murbot/.Pictures/AI/titans_secret.gif

Moogs

2005-01-24, 22:28

http://photojournal.jpl.nasa.gov/jpeg/PIA07236.jpg

:eek:

Holy shit. Not much grey area here (like Mars has) when talking about what caused the terrain to be formed as it is....

curiousuburb

2005-02-25, 13:55

Trogdor on Saturn

http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA06197-br402.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1399)

The Dragon Storm
February 24, 2005
Full-Res: PIA06197 (http://photojournal.jpl.nasa.gov/catalog/PIA06197)

A large, bright and complex convective storm that appeared in Saturn's southern hemisphere in mid-September 2004 was the key in solving a long-standing mystery about the ringed planet.

Saturn's atmosphere and its rings are shown here in a false color composite made from Cassini images taken in near infrared light through filters that sense different amounts of methane gas. Portions of the atmosphere with a large abundance of methane above the clouds are red, indicating clouds that are deep in the atmosphere. Grey indicates high clouds, and brown indicates clouds at intermediate altitudes. The rings are bright blue because there is no methane gas between the ring particles and the camera.

The complex feature with arms and secondary extensions just above and to the right of center is called the Dragon Storm. It lies in a region of the southern hemisphere referred to as "storm alley" by imaging scientists because of the high level of storm activity observed there by Cassini in the last year.

The Dragon Storm was a powerful source of radio emissions during July and September of 2004. The radio waves from the storm resemble the short bursts of static generated by lightning on Earth. Cassini detected the bursts only when the storm was rising over the horizon on the night side of the planet as seen from the spacecraft; the bursts stopped when the storm moved into sunlight. This on/off pattern repeated for many Saturn rotations over a period of several weeks, and it was the clock-like repeatability that indicated the storm and the radio bursts are related. Scientists have concluded that the Dragon Storm is a giant thunderstorm whose precipitation generates electricity as it does on Earth. The storm may be deriving its energy from Saturn's deep atmosphere.

One mystery is why the radio bursts start while the Dragon Storm is below the horizon on the night side and end when the storm is on the day side, still in full view of the Cassini spacecraft. A possible explanation is that the lightning source lies to the east of the visible cloud, perhaps because it is deeper where the currents are eastward relative to those at cloud top levels. If this were the case, the lightning source would come up over the night side horizon and would sink down below the day side horizon before the visible cloud. This would explain the timing of the visible storm relative to the radio bursts.

The Dragon Storm is of great interest for another reason. In examining images taken of Saturn's atmosphere over many months, imaging scientists found that the Dragon Storm arose in the same part of Saturn's atmosphere that had earlier produced large bright convective storms. In other words, the Dragon Storm appears to be a long-lived storm deep in the atmosphere that periodically flares up to produce dramatic bright white plumes which subside over time. One earlier sighting, in July 2004, was also associated with strong radio bursts. And another, observed in March 2004 and captured in a movie created from images of the atmosphere (http://photojournal.jpl.nasa.gov/catalog/PIA06082 and http://photojournal.jpl.nasa.gov/catalog/PIA06083) spawned three little dark oval storms that broke off from the arms of the main storm. Two of these subsequently merged with each other; the current to the north carried the third one off to the west, and Cassini lost track of it. Small dark storms like these generally get stretched out until they merge with the opposing currents to the north and south.

These little storms are the food that sustains the larger atmospheric features, including the larger ovals and the eastward and westward currents. If the little storms come from the giant thunderstorms, then together they form a food chain that harvests the energy of the deep atmosphere and helps maintain the powerful currents.

Cassini has many more chances to observe future flare-ups of the Dragon Storm, and others like it over the course of the mission. It is likely that scientists will come to solve the mystery of the radio bursts and observe storm creation and merging in the next 2 or 3 years.

curiousuburb

2005-03-09, 14:31

( Riddick not shown )

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA06199-br500.gif (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1411)
Cassini's Private Eclipse - March 3, 2005
Full-Res: PIA06199 (http://photojournal.jpl.nasa.gov/catalog/PIA06199)

Click here (http://www.jpl.nasa.gov/videos/caption/cassini/pia06199/start.qtl) for the QuickTime video.

For this movie, Cassini pointed its cameras toward Saturn's moon Dione to witness its distant sibling moon Rhea briefly pass behind in a series of 32 individual frames taken over 17 minutes. Four individual frames from the eclipse are shown at bottom.

Rhea (1,528 kilometers, or 949 miles across) is larger than Dione (1,118 kilometers, or 695 miles across), but also is farther away as seen here, which explains why the two moons appear to be roughly the same angular size.

The view shows principally the anti-Saturn side of Dione, and the Saturn-facing side of far-off Rhea.

The images in this movie were taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 20, 2005, at a distance of approximately 1.5 million kilometers (900,000 miles) from Dione and about 2.3 million kilometers (1.4 million miles) from Rhea. The image scale is approximately 9 kilometers (6 miles) per pixel on Dione and 14 kilometers (9 miles) per pixel on Rhea.

And new pictures of the South Polar region of Titan...

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA06203-br402.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1423)

They've also added some close-up views (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1422) of the Titan shots

curiousuburb

2005-03-09, 14:39

Unspecified caption yet, but this is the sunlit side...
looks like the F Ring and gap to A Ring just bulging into the center left edge.

It seems to me we can see the lit lower crescent of a moon inside and above the F Ring.
http://www.nasa.gov/images/content/61696main_soi7-516.jpg

You can also clearly see perturbations or 'wake' in the F ring, perhaps due to the nearby moon.

Images and briefing to come this morning.
New zoomed image of the F ring shows even more detail of wake perturbations and ringlets...
and I thought the first version was impressive...

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA06600-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1415)

In the Moon's Wake - March 8, 2005
Full-Res: PIA06600 (http://photojournal.jpl.nasa.gov/catalog/PIA06600)

Intriguing features resembling drapes and kinks are visible in this Cassini view of Saturn's thin F ring. Several distinct ringlets are present, in addition to the bright, knotted core of the ring.

The obvious structure in the ring and its strands has been caused by Prometheus, the inner F ring shepherd moon that recently swept past this region. (Prometheus is about 10 degrees ahead of the F ring material in this image). These types of features were first seen in images taken just after Cassini entered into orbit around Saturn. The gravitational interaction of Prometheus (102 kilometers, or 63 miles across) on the ring pulls material out the ring once every orbit (every 14.7 hours) as the moon gets close to the ring and its strands.

The image was taken with the Cassini spacecraft narrow-angle camera on Jan. 19, 2005, at a distance of approximately 1.9 million kilometers (1.2 million miles) from Saturn through a filter sensitive to polarized visible light. Resolution in the original image was 11 kilometers (7 miles) per pixel. The image was contrast-enhanced and magnified by a factor of two to aid visibility.

curiousuburb

2005-05-11, 18:12

Wavemaking Moon Discovered.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA06237-br402.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1521)
Discovery of the Wavemaker (movie)
May 10, 2005 Full-Res: PIA06238 (http://photojournal.jpl.nasa.gov/catalog/PIA06238)

Cassini's celestial sleuthing has paid off with this time-lapse series of images which confirmed earlier suspicions that a small moon was orbiting within the narrow Keeler gap of Saturn's rings.

The movie sequence, which consists of 12 images taken over 16 minutes while Cassini gazed down upon the sunlit side of the A ring, shows a tiny moon orbiting in the center of the Keeler gap, churning up waves in the gap edges as it goes. The pattern of waves travels with the moon in its orbit.

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA06238-br500.gif

The Keeler gap is located about 250 kilometers (155 miles) inside the outer edge of the A ring, which is also the outer edge of the bright main rings. The new object is about 7 kilometers across (4 miles) and reflects about 50 percent of the sunlight that falls upon it -- a brightness that is typical of particles in the nearby rings.

The new body has been provisionally named S/2005 S1.

Imaging scientists predicted the moon's presence and its orbital distance from Saturn after July 2004, when they saw a set of peculiar spiky and wispy features in the Keeler gap's outer edge. The similarities of the Keeler gap features to those noted in Saturn's F ring and the Encke gap led the scientists to conclude that a small body, a few kilometers across, was lurking in the center of the Keeler gap, awaiting discovery.

Also included here is a view of the same scene created by combining six individual, unmagnified frames used in the movie sequence. This digital composite view improves the overall resolution of the scene compared to that available in any of the single images.

The images in this movie sequence were obtained with the Cassini spacecraft narrow-angle camera on May 1, 2005, at a distance of approximately 1.1 million kilometers (708,000 miles) from Saturn. Resolution in the original image was 8 kilometers (5 miles) per pixel. The images in the movie sequence have been magnified in (the vertical direction only) by a factor of two to aid visibility of features caused within the gap by the moonlet.

So a newly discovered moon was predicted due to perturbations of the rings in its wake.
Confirmed!1!
Now Shipping!

In other moon news, Phoebe has now been confirmed as an interloper in the Saturn system from Pluto's neighbourhood. Those Kuiper belt kids can be cold bastards.

Moogs

2005-05-11, 19:50

It's official: this thread still rules.

curiousuburb

2005-05-25, 20:10

Scientists Baffled by Bright Spot on Titan

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG001543-br402.jpg (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=576)

Saturn's moon Titan shows an unusual bright spot that has scientists mystified. The spot, approximately the size and shape of West Virginia, is just southeast of the bright region called Xanadu and is visible to multiple instruments on the Cassini spacecraft.

The 483-kilometer-wide (300-mile) region may be a "hot" spot -- an area possibly warmed by a recent asteroid impact or by a mixture of water ice and ammonia from a warm interior, oozing out of an ice volcano onto colder surrounding terrain. Other possibilities for the unusual bright spot include landscape features holding clouds in place or unusual materials on the surface.

"At first glance, I thought the feature looked strange, almost out of place," said Dr. Robert H. Brown, team leader of the Cassini visual and infrared mapping spectrometer and professor at the Lunar and Planetary Laboratory, University of Arizona, Tucson. "After thinking a bit, I speculated that it was a hot spot. In retrospect, that might not be the best hypothesis. But the spot is no less intriguing."

The Cassini spacecraft flew by Titan on March 31 and April 16. Its visual and infrared mapping spectrometer, using the longest, reddest wavelengths that the spectrometer sees, observed the spot, the brightest area ever observed on Titan.

Cassini's imaging cameras saw a bright, 550-kilometer-wide (345-mile) semi-circle at visible wavelengths at this same location on Cassini's December 2004 and February 2005 Titan flybys. "It seems clear that both instruments are detecting the same basic feature on or controlled by Titan's surface," said Dr. Alfred S. McEwen, Cassini imaging team scientist, also of the University of Arizona. "This bright patch may be due to an impact event, landslide, cryovolcanism or atmospheric processes. Its distinct color and brightness suggest that it may have formed relatively recently."

... continues ...

Cool. Except for that hot spot.

curiousuburb

2005-06-17, 13:23

Just when you thought you'd seen the wobbly F ring wake well... < or F wing if you're elmer fudd >

Pandora's Flocks

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA07523-br500.jpg
June 17, 2005 Full-Res: PIA07523 (http://photojournal.jpl.nasa.gov/catalog/PIA07523)

The shepherd moon, Pandora, is seen here alongside the narrow F ring that it helps maintain. Pandora is 84 kilometers (52 miles) across.

Cassini obtained this view from about four degrees above the ringplane. Captured here are several faint, dusty ringlets in the vicinity of the F ring core. The ringlets do not appear to be perturbed to the degree seen in the core.

The appearance of Pandora here is exciting, as the moon's complete shape can be seen, thanks to reflected light from Saturn, which illuminates Pandora's dark side. The hint of a crater is visible on the dark side of the moon.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 4, 2005, at a distance of approximately 967,000 kilometers (601,000 miles) from Pandora and at a Sun-Pandora-spacecraft, or phase, angle of 117 degrees. The image scale is 6 kilometers (4 miles) per pixel.

Other releases of late include:
ring planehttp://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA07520-th100.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1566), F ringhttp://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA07522-th100.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1569) and volcano on Titanhttp://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07962-th100.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1560)

Debating whether to start a Deep Impact thread...

709

2005-06-17, 13:53

Debating whether to start a Deep Impact thread...Do it! We're less than a month away... :)

Er, shit...almost 2 weeks away I should say... :eek:

Time flies.

atomicbartbeans

2005-06-17, 20:33

Am I the only one that thinks all these pictures look photoshopped?

BarracksSi

2005-06-18, 00:13

Am I the only one that thinks all these pictures look photoshopped?

I can understand where you're coming from, but these are still just digital images, and by the time we see them, they're compressed just like any other pic, too.

The fun thing about Photoshop is that any of us can make false color images of stuff like this. I can take that last pic, change it to RGB, and mess around with levels & curves to make ring features stand out even more. I wonder if it's at all like NASA has been doing for years.

curiousuburb

2005-06-18, 11:11

In general terms, PS is used to optimize and combine data in each colour channel... as to how...
while not specific to Cassini, we can look at the published info on Hubble...

Behind the Photos - http://hubblesite.org/sci.d.tech/behind_the_pictures/

Slate summarizes the process. - http://slate.msn.com/id/2120008/

PhotoShop Filters and Hubble - http://hubblesource.stsci.edu/services/articles/2005-02-10/

curiousuburb

2005-06-28, 21:36

Possible Lake on Titan (with animated clouds)

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA06241-br500.gif (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=583)
NASA's Cassini Reveals Lake-like Feature on Titan
June 28, 2005
(Source: Jet Propulsion Laboratory)

This view of Titan's south polar region reveals an intriguing dark feature that may be the site of a past or present lake of liquid hydrocarbons.
+ See Time-Lapse Movie
Scientists are fascinated by a dark, lake-like feature recently observed on Saturn's moon Titan. NASA's Cassini spacecraft captured a series of images showing a marking, darker than anything else around it. It is remarkably lake-like, with smooth, shore-like boundaries unlike any seen previously on Titan.

"I'd say this is definitely the best candidate we've seen so far for a liquid hydrocarbon lake on Titan," said Dr. Alfred McEwen, Cassini imaging team member and a professor at the University of Arizona, Tucson. The suspected lake area measures 234 kilometers long by 73 kilometers wide (145 miles by 45 miles), about the size of Lake Ontario, on the U.S. Canadian border.

"This feature is unique in our exploration of Titan so far," said Dr. Elizabeth Turtle, Cassini imaging team associate at the University of Arizona. "Its perimeter is intriguingly reminiscent of the shorelines of lakes on Earth that are smoothed by water erosion and deposition."

The feature lies in Titan's cloudiest region, which is presumably the most likely site of recent methane rainfall. This, coupled with the shore-like smoothness of the feature's perimeter makes it hard for scientists to resist speculation about what might be filling the lake, if it indeed is one.

"It's possible that some of the storms in this region are strong enough to make methane rain that reaches the surface," said Cassini imaging team member Dr. Tony DelGenio of NASA's Goddard Institute for Space Studies in New York.

"Given Titan's cold temperatures, it could take a long time for any liquid methane collecting on the surface to evaporate. So it might not be surprising for a methane-filled lake to persist for a long time," DelGenio added. Despite earlier predictions, no definitive evidence for open bodies of liquid has been found on Titan. Cassini has not yet been in a favorable position for using its cameras to check for glints from possible surface liquids in the south polar region.

"Eventually, as the seasons change over a few years, the convective clouds may migrate northward to lower latitudes," said DelGenio, "If so, it will be interesting to see whether the Cassini cameras record changes in the appearance of the surface as well."

"An alternate explanation is that this feature was once a lake, but has since dried up, leaving behind dark deposits," Turtle said. Yet another possibility is that the lake is simply a broad depression filled by dark, solid hydrocarbons falling from the atmosphere onto Titan's surface. In this case, the smooth outline might be the result of a process unrelated to rainfall, such as a sinkhole or a volcanic caldera.

"It reminds me of the lava lakes seen on Jupiter's moon, Io," Dr. Torrence Johnson, an imaging team member at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

"It is already clear that whatever this lake-like feature turns out to be, it is only one of many puzzles that Titan will throw at us as we continue our reconnaissance of the surface over the next few years," said Dr. Carolyn Porco, imaging team leader at the Space Science Institute in Boulder, Colo.

Thirty-nine more Titan flybys are planned for Cassini's prime mission. In future flybys the science teams will search for opportunities to observe the lake feature again and to look for mirror-like reflections from smooth surfaces elsewhere on Titan. Such reflections would strongly support the presence of liquids.

for more info, or the alternate cloud caption, click here (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1581)

Kickaha

2005-07-02, 01:33

curiousuburb

2005-07-02, 03:05

Not only do the rings have an O2 atmosphere of sorts, but Saturn is rotating slower than when Voyager and Pioneer went by? <jon_stewart>whaaaaaaaaaaa?</jon_stewart>

http://news.bbc.co.uk/2/hi/science/nature/4640641.stm

Two words: Fun. Key.

(Yes, easiest explanation is that the sensor data somehow differs between then and now, or the interpretation methodology.)
So the rings have an oxygen atmosphere and an energy source... I see a new sci-fi ecosystem set for novelization or hollywood.

You read it here first. Kickaha and I (on behalf of AN) claim royalties.

curiousuburb

2005-07-06, 12:50

And for a non-Cassini perspective for a change, Space.com (http://www.space.com/imageoftheday/image_of_day_050704.html) offers Saturn in Visible and X-Ray

http://a52.g.akamaitech.net/f/52/827/1d/www.space.com/images/050704_saturn_xrayopt_04.jpg (http://www.space.com/imageoftheday/image_of_day_050704.html)
Sparkling Saturn

Saturn's rings light up with bright blue highlights, in this blend of both visual and X-ray observations.

Astronomers believe that fluorescence caused when solar X-rays smack into the oxygen molecules locked with in Saturn�s icy ring water.

As seen in this image, most of the X-rays among Saturn�s rings come from the B ring, the bright white, inner ring in the optical image of the planet.

There is some evidence for a concentration of X-rays on the morning side (left side, also called the East ansa) of the rings, possibly because X-rays are associated with optical features called spokes that are largely confined to the dense B ring and most often seen on the morning side.

Spokes are due to transient clouds of fine ice-dust particles that are lifted off the ring surface. It has been suggested that the spokes are triggered by meteoroid impacts, which are more likely in the midnight to early morning hours because during that period the relative speed of the rings through a cloud of meteoroids would be greater.

The higher X-ray brightness on the morning side of the rings could be due to the additional solar fluorescence from the transient ice clouds that produce the spokes. This explanation may also account for other Chandra observations of Saturn, which show that the X-ray brightness of the rings varies significantly from one week to the next.

Credit: X-ray: NASA/MSFC/CXC/A.Bhardwaj et al.; Optical: NASA/ESA/STScI/AURA

They have previously reported on puzzling results from science in these bands and compared Chandra and HST

http://www.space.com/images/h_xray_saturn_02.jpg (http://www.space.com/scienceastronomy/xray_saturn_040308.html)
Chandra's image of Saturn held some surprises for the observers. First, Saturn's 90 megawatts of X-radiation is concentrated near the equator. This is different from a similar gaseous giant planet, Jupiter, where the most intense X-rays are associated with the strong magnetic field near its poles.
Credit: X-ray: NASA/U. Hamburg/J.Ness et al; Optical: NASA/STScI

curiousuburb

2005-07-26, 05:10

Hot on the heels of the recent Top 10 Cassini Science Highlights (http://saturn.jpl.nasa.gov/news/features/feature20050715.cfm),

check out the latest spooky Sounds of Saturn (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=589)

http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA07967-br500.jpg click for 127kb WAV file (http://saturn.jpl.nasa.gov/multimedia/images/saturn/audio/pia07967-072504.wav)
Saturn's radio emissions could be mistaken for a Halloween sound track. That's how two researchers describe their recent findings, published in the July 23 issue of the Geophysical Research Letters. Their paper is based on data from the Cassini spacecraft radio and plasma wave science instrument. The study investigates sounds that are not just eerie, but also descriptive of a phenomenon similar to Earth's northern lights.

"All of the structures we observe in Saturn's radio spectrum are giving us clues about what might be going on in the source of the radio emissions above Saturn's auroras," said Dr. Bill Kurth, deputy principal investigator for the instrument. He is with the University of Iowa, Iowa City. Kurth made the discovery along with Principal Investigator Don Gurnett, a professor at the University. "We believe that the changing frequencies are related to tiny radio sources moving up and down along Saturn's magnetic field lines."

Samples of the resulting sounds can be heard at www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://www-pw.physics.uiowa.edu/cassini/ .

The radio emissions, called Saturn kilometric radiation, are generated along with Saturn's auroras, or northern and southern lights. Because the Cassini instrument has higher resolution compared to a similar instrument on NASA's Voyager spacecraft, it has provided more detailed information on the spectrum and the variability of radio emissions. The high-resolution measurements allow scientists to convert the radio waves into audio recordings by shifting the frequencies down into the audio frequency range.

The terrestrial cousins of Saturn's radio emissions were first reported in 1979 by Gurnett, who used an instrument on the International Sun-Earth Explorer spacecraft in Earth orbit. Kurth said that despite their best efforts, scientists still haven't agreed on a theory to fully explain the phenomenon. They will get another chance to solve the radio emission puzzle beginning in mid-2008 when Cassini will fly close to, or possibly even through, the source region at Saturn. Gurnett said, "It is amazing that the radio emissions from Earth and Saturn sound so similar." Other contributors to the paper include University of Iowa scientists George Hospodarsky and Baptiste Cecconi; Mike Kaiser (currently at Goddard Space Flight Center, Greenbelt, Md.); French scientists Philippe Louarn, Philippe Zarka and Alain Lecacheux; and Austrian scientists Helmut Rucker and Mohammed Boudjada. Cassini, carrying 12 scientific instruments, on June 30, 2004, became the first spacecraft to orbit Saturn. It is conducting a four-year study of the planet, its rings and many moons. The spacecraft carried the Huygens probe, a six-instrument European Space Agency probe that landed on Titan, Saturn's largest moon, in January 2005.

curiousuburb

2005-09-30, 06:47

Spongy and Lavalike moons and more

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07740-br402.jpg (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=97) Hyperion

Click pic above for links to QT movie of Hyperion flyby.

Cassini performed back-to-back flybys of Saturn moons Tethys and Hyperion last weekend, coming closer than ever before to each of them. Tethys has a scarred, ancient surface, while Hyperion is a strange, spongy-looking body with dark-floored craters that speckle its surface.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG001750-th100.jpg (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=605) Click for news of 'doubleheader' flyby.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07737-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1759)
False colour close-up of Tethys. Click for details.

This view is among the closest Cassini images of Tethys' icy surface taken during the Sept. 24, 2005 flyby.
This false-color image, created with infrared, green and ultraviolet frames, reveals a wide variety of surface colors across this terrain. The presence of this variety at such small scales may indicate a mixture of different surface materials. Tethys was previously known to have color differences on its surface, especially on its trailing side, but this kind of color diversity is new to imaging scientists. For a clear-filter view of this terrain, see PIA07736 (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1758).

Brad

2005-10-01, 21:46

Keep up the posts, 'burb! While it may not be generating a lot of discussion here, I find the information from these links fascinating and am glad you're posting them. :)

Moogs

2005-10-01, 22:13

Wow...

...Hyperion is really strange looking. Almost expect a place like that to have little demonic aliens lying in wait.

curiousuburb

2005-10-06, 07:07

F ring detail (and damage)...

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07601-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1768)

Drawing the Drapes
October 5, 2005 Full-Res: PIA07601 (http://photojournal.jpl.nasa.gov/catalog/PIA07601)

Prometheus poses here with its latest creation: a dark, diagonal gore in the tenuous material interior to Saturn's F ring. The shepherd moon creates a new gore each time it comes closest to the F ring in its orbit of Saturn, and the memory of previous passes is preserved in the rings's structure for some time afterward. Prometheus is 102 kilometers (63 miles) across.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 20, 2005, at a distance of approximately 499,000 kilometers (310,000 miles) from Saturn and at a high Sun-Saturn-spacecraft, or phase, angle of 144 degrees. Resolution in the original image was 3 kilometers (2 miles) per pixel.

curiousuburb

2005-10-18, 17:57

Cassini's latest stunning pic...

Ringside with Dione

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07744-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1790)

October 17, 2005 Full-Res: PIA07744 (http://photojournal.jpl.nasa.gov/catalog/PIA07744)

Speeding toward pale, icy Dione, Cassini's view is enriched by the tranquil gold and blue hues of Saturn in the distance. The horizontal stripes near the bottom of the image are Saturn's rings. The spacecraft was nearly in the plane of the rings when the images were taken, thinning them by perspective and masking their awesome scale. The thin, curving shadows of the C ring and part of the B ring adorn the northern latitudes visible here, a reminder of the rings' grandeur.
It is notable that Dione, like most of the other icy Saturnian satellites, looks no different in natural color than in monochrome images.

Images taken on Oct. 11, 2005, with blue, green and infrared (centered at 752 nanometers) spectral filters were used to create this color view, which approximates the scene as it would appear to the human eye. The images were obtained with the Cassini spacecraft wide-angle camera at a distance of approximately 39,000 kilometers (24,200 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 22 degrees. The image scale is about 2 kilometers (1 mile) per pixel.

and Flicks

QuickTime (sm, no audio) (3.5 MB) (http://saturn.jpl.nasa.gov/multimedia/videos/movies/PIA07749_half_movie.mov) http://ciclops.org/media/ir/2005/1568_3890_0.gif QuickTime (lg, no audio) (9.9 MB) (http://saturn.jpl.nasa.gov/multimedia/videos/movies/PIA07749_full_movie.mov)

Ice Moon Rendezvous Full-Res: PIA07749 (http://photojournal.jpl.nasa.gov/catalog/PIA07749)

Zooming in closer and closer, this movie chronicles Cassini's targeted flyby of Dione, with Saturn and its lovely rings forming a dramatic backdrop.
The movie begins with Cassini during its approach about 107,000 kilometers (66,000 miles) from the icy moon. Few surface details are discernable from this distance, but the view quickly improves. The movie jumps to a point 39,000 kilometers (24,000 miles) from Dione, with Saturn's atmosphere now in the background and draped by threadlike ring shadows.

As the spacecraft gets still closer, the camera focuses on bright fractures in the west. It becomes apparent that these braided canyons slice through older craters. At the closest point in this approach sequence, Cassini is about 4,000 kilometers (2,500 miles) above Dione's surface and the image scale is 234 meters (768 feet) per pixel. For a narrow-angle camera image taken at almost the same instant see PIA07748. (http://photojournal.jpl.nasa.gov/catalog/PIA07748)

A dramatic shift in perspective follows, with Cassini moving past the point of closest approach and staring at a large crater on Dione's receding limb. Steep cliffs gleam in the sunlight as the intrepid craft pulls away. About three and a half hours have elapsed since the first image in the movie was taken.

This movie was created from clear-filter images taken during the Oct. 11, 2005, flyby of Dione. All images except the departing view were obtained with the Cassini spacecraft wide-angle camera.

You can clearly see the central peak in the receding crater in the final shots of the movie, and in both the main image and both movies you really get a sense of just how thin the rings are. The ring shadow on Saturn is a nice touch, too.

Brilliant stuff.

julesstoop

2005-10-18, 18:10

From the same release, check the extremely hi-rez (7600*2000 pix.) image of Dione's crescent Cassini took when looking back:

http://ciclops.org/view.php?id=1584

curiousuburb

2005-10-18, 18:19

From the same release, check the extremely hi-rez (7600*2000 pix.) image of Dione's crescent Cassini took when looking back:

http://ciclops.org/view.php?id=1584
Damn, that looks cold...

curiousuburb

2005-10-31, 05:25

For a switch of senses as a seasonal trick/treat, click the link for

http://saturn.jpl.nasa.gov/multimedia/sounds/images/sounds_of_saturn_01_578.jpg (http://saturn.jpl.nasa.gov/multimedia/sounds/)

oldmacfan

2005-10-31, 10:10

Stunning pics

curiousuburb

2005-12-07, 08:31

And you think it's cold where you are...

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07767-br402.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1889)

Season of Moons
December 6, 2005 Full-Res: PIA07767 (http://photojournal.jpl.nasa.gov/catalog/PIA07767
)

This montage shows four major icy moons of Saturn that the Cassini spacecraft visited while surveying the Saturnian system during 2005. Even though all of these bodies are made largely of ice, they exhibit remarkably different geological histories and varied surface features.
Craters from meteorite impacts are common features on all of these moons. But since the major moons of Saturn are thought to have all formed at approximately the same time, the different distribution of sizes, shapes and numbers of craters on each of their surfaces tell scientists a great deal about the differences in their geologic histories.

Rhea and Iapetus are thoroughly peppered by impacts, suggesting their surfaces have been exposed to the shooting gallery of space for eons. Dione appears to have regions of terrain that are smoother, with fewer craters, suggesting a slightly younger surface. Dione also has a large system of bright, braided fractures that suggest tectonic activity took place there some time after the moon first formed.

Enceladus, however, possesses a region of terrain near its south pole (shown here), that is so dramatically devoid of impact sites that scientists suspected it was geologically active in the recent past, and perhaps even today. The discovery this year of material jetting from the pole and creating a great plume of icy particles confirmed these suspicions. See Fountains of Enceladus (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1873) for images of the Enceladus plume.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07758-th200.jpghttp://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07759-th200.jpgMore on the Enceladus Plume (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=619) http://saturn.jpl.nasa.gov/multimedia/videos/movies/PIA07762_full_movie.gif
Click for links to QT Movie (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=104)

The processes that power the activity on Enceladus remain elusive, as do those that produced the pronounced equatorial bulge on Iapetus. This feature was imaged for the first time by Cassini during a flyby of Iapetus that began New Year's Day. The bulge on Iapetus reaches 20 kilometers (12 miles) above the surrounding terrain in places, making it one of the tallest features in the solar system.

Like many scientific journeys, Cassini's historic survey of Saturn's moons has raised more questions. For example, why small Enceladus (505 kilometers, or 314 miles across) is presently geologically active while much larger Rhea (1,528 kilometers, or 949 miles across) is not. Fortunately, such puzzles are the most exciting sort for scientists interested in uncovering the secrets of Saturn's realm.

Also of note recently have been more releases on Titan, including movies of the descent and landing site calculated from the last imaging flyby (some with radar).
http://uanews.org/silk/huygens_landsite.jpgDescent Imager (http://uanews.org/cgi-bin/WebObjects/UANews.woa/7/wa/MainStoryDetails?ArticleID=12045) Landing site movie (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=102) http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA06440-th100.jpgDescent movie (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=101)

The Nov 30th ESA Press conference on Mars Express and Huygens results is now online http://www.esa.int/images/mars_and_titan_160x50.jpg (http://www.esa.int/SPECIALS/Results_from_Mars_Express_and_Huygens/SEM951VLWFE_0.html)

curiousuburb

2005-12-15, 10:15

Ring Shepherds and Deformation Trails.

In honour of the Forum update and it's scrollable individual posts, I'm including a slightly crisper image here than the usual clickable size, mostly to showcase the trailing ice particles from the F ring which are following Prometheus (at left) out of the ring plane (although apparently following behind Pandora on the right).

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA07653-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1903)

Close to the Shepherd Moons
December 15, 2005 Full-Res: PIA07653 (http://photojournal.jpl.nasa.gov/catalog/PIA07653)

This spectacular image shows Prometheus (at left) and Pandora (at right), with their flock of icy ring particles (the F ring) between them. Pandora is exterior to the ring, and closer to the spacecraft here. Each of the shepherd satellites has an unusual shape, with a few craters clearly visible.
The effect of Prometheus (102 kilometers, or 63 miles across) on the F ring is visible as it pulls material out of the ring when it is farthest from Saturn in its orbit. Pandora is 84 kilometers (52 miles) across.

The image was taken in polarized green light with the Cassini spacecraft narrow-angle camera on Oct. 29, 2005, at a distance of approximately 459,000 kilometers (285,000 miles) from Pandora and 483,500 kilometers (300,500 miles) from Prometheus. The image scale is 3 kilometers (2 miles) per pixel on Pandora and 3 kilometers (2 miles) per pixel on Prometheus. The view was acquired from about a third of a degree below the ringplane.

The image from a few days ago showed further deformation in the edge of the F ring when viewed edge on.

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA07651-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1901)

On the Edge
December 13, 2005 Full-Res: PIA07651 (http://photojournal.jpl.nasa.gov/catalog/PIA07651)

Viewing Saturn's rings very close to edge-on produces some puzzling effects, as these two images of the F ring demonstrate.
The upper image was acquired from less than a tenth of a degree beneath the ringplane and shows a mysterious bulge. Such a feature has not been seen previously by the Cassini spacecraft from this angle. It is possible that, because of the very shallow viewing angle, the Cassini spacecraft's view takes a long path through the ring, making very faint material visible. It also may be that an embedded object of a kilometer or so in size stirs up the neighboring ring particles to create a bulge. Alternatively, an impact into an embedded moonlet that was covered with debris could produce a cloud like this.

Images taken by the Voyager spacecrafts showed clumps that might have been produced in these ways. Cassini's investigations will help to determine the vertical extent of such clumps and understand their origins.

The lower image was obtained from less than a hundredth of a degree beneath the ringplane. Across the center of the rings is a dark lane, giving them an appearance not unlike that of a spiral galaxy, seen edge-on.

Both images were taken using the clear spectral filters (predominantly visible light) on the Cassini spacecraft narrow-angle camera. The images have been magnified by a factor of two.

The top image was obtained at a distance of 3.6 million kilometers (2.2 million miles) from Saturn on Nov. 11, 2005 and shows wispy fractures on Dione's trailing hemisphere. The image scale is 22 kilometers (14 miles) per pixel. The bottom image was acquired at a distance of 2.5 million kilometers (1.6 million miles) from Saturn on Nov. 5, 2005. The image scale is 15 kilometers (9 miles) per pixel.

Keeners might also be interested in some new false colour images of Dionne and Rhea http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07769-th120.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1891) and Hyperion http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07768-th120.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1890), as well as new images of clouds in the upper atmosphere, which the NASA/ESA folks are describing as "cirrus-like" http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA07650-th120.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1900)

curiousuburb

2006-03-03, 07:34

Updates:

Relief on Iapetus, the two-faced Moon

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07125-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2015)

To the Relief of Iapetus
March 2, 2006 Full-Res: PIA08125 (http://photojournal.jpl.nasa.gov/catalog/PIA08125)

Sunlight strikes the terminator (the boundary between day and night) region on Saturn's moon Iapetus at nearly horizontal angles, making visible the vertical relief of many features.
This view is centered on terrain in the southern hemisphere of Iapetus (1,468 kilometers, or 912 miles across). Lit terrain visible here is on the moon's leading hemisphere. In this image, a large, central-peaked crater is notable at the boundary between the dark material in Cassini Regio and the brighter material on the trailing hemisphere.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 22, 2006, at a distance of approximately 1.3 million kilometers (800,000 miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 67 degrees. Resolution in the original image was 8 kilometers (5 miles) per pixel. The image has been magnified by a factor of two and contrast-enhanced to aid visibility.

Titan's Hood through the Haze (with Tethys on the left)

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08124-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2014)

Saturnian Specters
March 1, 2006 Full-Res: PIA08124 (http://photojournal.jpl.nasa.gov/catalog/PIA08124)

Ghostly details make this dark scene more than just a beautiful grouping of two Saturn moons, with Tethys on the left and Titan on the right. In Titan's thick and inflated atmosphere, the detached high haze layer can be seen, as well as the complex northern polar hood (at the top). Images like this one can help scientists make definitive estimates of the altitudes to which the high haze extends.
The faint vertical banded pattern is a type of noise that usually is removed during image processing. Because this image was processed to enhance the visibility of details in Titan's atmosphere and the faint G ring, the vertical noise was also enhanced.

Titan is Saturn's largest moon, at 5,150 kilometers (3,200 miles) across. Tethys is 1,071 kilometers (665 miles) across.

This view was obtained in visible light with the Cassini spacecraft narrow-angle camera on Jan. 19, 2006, at a distance of approximately 2.4 million kilometers (1.5 million miles) from Titan and 1 million kilometers (600,000 miles) from Tethys. The image scale is 14 kilometers (9 miles) per pixel on Titan and 6 kilometers (4 miles) per pixel on Tethys.

And the latest shot of the edge of the F Ring seems to show a spiral pattern...

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA08123-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2013)

F Ring Edge
February 28, 2006 Full-Res: PIA08123 (http://photojournal.jpl.nasa.gov/catalog/PIA08123)

Structure in Saturn's narrow and complex F ring is seen here, including one of the faint strands (at the left) that Cassini has shown to curl around the planet in a tight, rotating spiral. Scientists think the spiral structure might be due to disturbance of micron-sized F-ring particles by a tiny moon (or moons).
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 19, 2006, at a distance of approximately 1.2 million kilometers (700,000 miles) from Saturn and from just above the ringplane. The image scale is 7 kilometers (4 miles) per pixel.

Moogs

2006-03-09, 20:18

Interesting find today!

The orbiting Cassini spacecraft has spotted what appear to be water geysers on one of Saturn's icy moons, raising the tantalizing possibility that the celestial object harbors life.

The surprising images from the moon Enceladus represent some of the most dramatic evidence yet that water in liquid form may be present beyond the Earth.

Excited by the discovery, some scientists said Enceladus should be added to the short list of places within the solar system most likely to have extraterrestrial life.

curiousuburb

2006-03-09, 20:47

Interesting find today!
Dude, I was just going to update this thread with the CNN story...

;)

Here's the full version:

http://www.boingboing.net/200603091121.jpg

Full text of teh CNN article. (http://edition.cnn.com/2006/TECH/space/03/09/enceladus.water.ap/)

The Cassini spacecraft has found evidence of liquid water spewing from geysers on one of Saturn's icy moons,[/b] raising the tantalizing possibility that the celestial object harbors life.

The surprising discovery excited some scientists, who say the Saturn moon, Enceladus, should be added to the short list of places within the solar system most likely to have extraterrestrial life.

Recent high-resolution images snapped by the orbiting Cassini confirmed the eruption of icy jets and giant water vapor plumes from geysers resembling frozen Old Faithfuls at Enceladus' south pole. (Watch NASA's Dr. Torrence Johnson talk about the importance of finding liquid water on Enceladus -- 1:22)

"We have the smoking gun" that proves the existence of water, said Carolyn Porco, a Cassini imaging scientist from the Space Science Institute in Boulder, Colorado.

If Enceladus does harbor life, it probably consists of microbes or other primitive organisms capable of living in extreme conditions, scientists say.

The findings were published in Friday's issue of the journal Science.

David Morrison, a senior scientist at NASA's Astrobiology Institute, cautioned against rushing to judgment about whether the tiny moon could support life. Scientists generally agree habitats need several ingredients for life to emerge, including water, a stable heat source and the right chemical recipe.

"It's certainly interesting, but I don't see how much more you can say beyond that," Morrison said.

Scientists believe Mars and Jupiter's icy moons might have -- or once had -- conditions hospitable to life.

Saturn is around 800 million miles from Earth. Enceladus measures 314 miles (505 kilometers) across and is the shiniest object in the solar system.

It was long thought to be cold and still. But scientists now believe it is a geologically active moon that possesses an unusually warm south pole.

The water is believed to vent from fissures in the south pole. Porco said the venting has probably been going on for at least several thousand years, potentially providing a lasting heat source.

The Cassini-Huygens mission is a joint NASA-European Space Agency project. The spacecraft was launched in 1997 and went into orbit around Saturn in 2004, exploring its spectacular rings and many moons.

Cassini made three flybys of Enceladus last year and is expected to fly within 220 miles (354 kilometers) of the moon again in 2008.

NASA version (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=639)

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07798-br402.jpg

http://www.space.com/images/050815_enceladus_temp_02.jpg

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07799-br500.jpg Click for details (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2026)

Moogs

2006-03-09, 20:54

Niiiice. :)

curiousuburb

2006-03-30, 09:22

Crank up the Katie Melua and get another rewrite for her bicycle tune...

Cassini Team adds to the Saturnian Moon count...

+10 Million Moonlets (propellers)

http://photojournal.jpl.nasa.gov/browse/PIA07792.jpg (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=643)

Cassini Finds 'Missing Link' Moonlet Evidence in Saturn's Rings
March 29, 2006

Scientists with NASA's Cassini mission have found evidence that a new class of small moonlets resides within Saturn's rings. There may be as many as 10 million of these objects within one of Saturn's rings alone. The propeller moonlets represent a hitherto unseen size-class of particles orbiting within the rings.

The moonlets' existence could help answer the question of whether Saturn's rings were formed through the break-up of a larger body or are the remnants of the disk of material from which Saturn and its moons formed.

"These moonlets are likely to be chunks of the ancient body whose break-up produced Saturn's glorious rings," said Joseph Burns of Cornell University, Ithaca, N.Y., a co-author of the report.

Careful analysis of high-resolution images taken by Cassini's cameras revealed four faint, propeller-shaped double streaks. These features were found in an otherwise bland part of the mid-A Ring, a bright section in Saturn's main rings. Cassini imaging scientists reporting in this week's edition of the journal Nature believe the "propellers" provide the first direct observation of how moonlets of this size affect nearby particles. Cassini took the images as it slipped into Saturn orbit on July 1, 2004.

Previous measurements, including those made by NASA's Voyager spacecraft in the early 1980s, have shown that Saturn's rings contain mostly small water-ice particles ranging from less than 1 centimeter (one-half inch) across to the size of a small house. Scientists knew about two larger embedded ring moons such as 30-kilometer-wide (19-mile) Pan and 7-kilometer-wide (4-mile) Daphnis. The latest findings mark the first evidence of objects of about 100 meters (300 feet) in diameter. From the number of moonlets spotted in the very small fraction of the A ring seen in the images, scientists estimated the total number of moonlets to be about 10 million.

"The discovery of these intermediate-sized bodies tells us that Pan and Daphnis are probably just the largest members of the ring population, rather than interlopers from somewhere else," said Matthew Tiscareno, an imaging team research associate at Cornell and lead author on the Nature paper.

Moons as large as Pan and Daphnis clear large gaps in the ring particles as they orbit Saturn. In contrast, smaller moonlets are not strong enough to clear out the ring, resulting in a partial gap centered on the moonlet and shaped like an airplane propeller. Such features created by moonlets were predicted by computer models, which give scientists confidence in their latest findings.

"We acquired this spectacular, one-of-a-kind set of images immediately after getting into orbit for the express purpose of seeing fine details in the rings that we had not seen previously," said Carolyn Porco, Cassini imaging team leader and co-author. "This will open up a new dimension in our exploration of Saturn's rings and moons, their origin and evolution."

The detection of moonlets embedded in a ring of smaller particles may provide an opportunity to observe the processes by which planets form in disks of material around young stars, including our own early solar system. "The structures we observe with Cassini are strikingly similar to those seen in many numerical models of the early stages of planetary formation, even though the scales are dramatically different," said co-author Carl Murray, an imaging team member at Queen Mary, University of London. "Cassini is giving us a unique insight into the origin of planets."

Locating the Propellers
March 29, 2006 Full-Res: PIA07792 (http://photojournal.jpl.nasa.gov/catalog/PIA07792)

This collection of Cassini images provides context for understanding the location and scale of propeller-shaped features observed within Saturn's A ring.
Careful analysis of the highest resolution images taken by Cassini's cameras as the spacecraft slipped into Saturn orbit revealed the four faint, propeller-shaped double-streaks in an otherwise bland part of the mid-A ring. Imaging scientists believe the "propellers" provide the first direct observation of the dynamical effects of moonlets approximately 100 meters (300 feet) in diameter. The propeller moonlets represent a hitherto unseen size-class of particles orbiting within the rings.

The left-hand panel provides broad context within the rings, and shows the B ring, Cassini Division, A ring and F ring. Image scale in the radial, or outward from Saturn, direction is about 45 kilometers (28 miles) per pixel; because the rings are viewed at an angle, the image scale in the longitudinal, or circumferential, direction is several times greater.

The center image is a closer view of the A ring, showing the radial locations where propeller features were spotted. The view is approximately 1,800 kilometers (1,100 miles) across from top to bottom and includes a large density wave at bottom (caused by the moons Janus and Epimetheus), as well as two smaller density waves. The footprints of the propeller discovery images are between density waves, in bland, quiescent regions of the ring.

The propellers appear as double dashes in the two close-up discovery images at the right and are circled. The unseen moonlets, each roughly the size of a football field, lie in the center of each structure. These two images were taken during Saturn orbit insertion on July 1, 2004, and are presented here at one-half scale. Resolution in the original images was 52 meters (171 feet) per pixel. The horizontal lines in the image represent electronic noise and do not correspond to ring features.

The propellers are about 5 kilometers (3 miles) long from tip to tip, and the radial offset (the "leading" dash is slightly closer to Saturn) is about 300 meters (1,000 feet).

The propeller structures are unchanged as they orbit the planet. In that way, they are much like the wave pattern that trails after a speedboat as it skims across a smooth lake. Such a pattern is hard to discern in a choppy sea. In much the same way, scientists think other effects may be preventing Cassini from seeing the propellers except in very bland parts of the rings.

See Four Propellers http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA07790-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2061) and Propeller Motion http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA07791-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2062) for additional images showing these features.

That's an awful lot of new names to come up with... :p

drewprops

2006-04-06, 00:06

The NOVA show on Saturn is running right now, which coincides with my current reading material, Ben Bova's Saturn. Fun!

curiousuburb

2006-04-19, 07:15

Lovely new image as an update...

Combinations of cloud patterns, ring shadow detail, thin ring plane, and moons...

http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA08159-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2085)

A Complex Crescent
April 18, 2006 Full-Res: PIA08159 (http://photojournal.jpl.nasa.gov/catalog/PIA08159)

The tilted crescent of Saturn displays lacy cloud bands here along with a bright equatorial region and threadlike ring shadows on the northern hemisphere.
Three moons are visible here. Mimas (397 kilometers, or 247 miles across) at left and faint, is aligned with the ringplane. At right are Rhea (1,528 kilometers, or 949 miles across, at top) and Tethys (1,071 kilometers, or 665 miles across, below Rhea).

The image was taken in polarized infrared light with the Cassini spacecraft wide-angle camera on March 11, 2006, at a distance of approximately 2.8 million kilometers (1.8 million miles) from Saturn. The image scale is 166 kilometers (103 miles) per pixel.

curiousuburb

2006-05-06, 08:45

New Videos of Titan landing

New views of the most distant touchdown ever made by a spacecraft are being released today by NASA, the European Space Agency and the University of Arizona. The movies show the dramatic descent of the Huygens probe to the surface of Saturn's moon Titan on Jan. 14, 2005.

The movies were put together with data collected by the Descent Imager/Spectral Radiometer instrument during the probe's 147-minute plunge through Titan's thick orange-brown atmosphere to a soft sandy riverbed. The Descent Imager/Spectral Radiometer was funded by NASA.

The data were analyzed for months after the landing and represent the best visual product obtained from the Huygens mission. It is the most realistic way yet to experience the Huygens probe landing. The movie "View from Huygens on Jan. 14, 2005," provides in 4 minutes and 40 seconds of what the probe actually "saw" during the 2.5 hours of the descent and touchdown.

"At first, the Huygens camera just saw fog over the distant surface," said Erich Karkoschka, team member at the University of Arizona, Tucson, and creator of the movies. "The fog started to clear only at about 60 kilometers [37 miles] altitude, making it possible to resolve surface features as large as 100 meters [328 feet]," he said. "But only after landing could the probe's camera resolve little grains of sand millions and millions of times smaller than Titan. A movie is a perfect medium to show such a huge change of scale."

For the second movie, scientists used artistic license and added sound to represent the different data sets collected. They re-created a scientifically accurate representation of the mission life in less than five minutes.

"These movies really demonstrate that the Huygens camera was very well designed for the job," said Jean-Pierre Lebreton, Huygens project scientist and mission manager at the European Space Agency. "They show so many different details of a landscape that covers only a tiny fraction -- one-thousandth -- of Titan's surface. This makes me dream of what a possible future mission to Titan may return of this wonderful and fascinating Earth-like world," he said.

New Titan Descent Movie (Now with Bells and Whistles)

http://saturn.jpl.nasa.gov/multimedia/images/videothumbnails/images/IMG002108-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=116)

10MB QT Animation (http://saturn.jpl.nasa.gov/multimedia/videos/movies/PIA08117.mov)

This movie, built with data collected during the European Space Agency's Huygens probe on Jan. 14, 2005, shows the operation of the Descent Imager/Spectral Radiometer camera during its descent and after touchdown. The camera was funded by NASA.
The almost four-hour-long operation of the camera is shown in less than five minutes. That's 40 times the actual speed up to landing and 100 times the actual speed thereafter.

The first part of the movie shows how Titan looked to the camera as it acquired more and more images during the probe's descent. Each image has a small field of view, and dozens of images were made into mosaics of the whole scene.

The scientists analyzed Huygens' speed, direction of motion, rotation and swinging during the descent. The movie includes sidebar graphics that show:

(Lower left corner) Huygens' trajectory views from the south, a scale bar for comparison to the height of Mount Everest, colored arrows that point to the sun and to the Cassini orbiter.
(Top left corner) A close-up view of the Huygens probe highlighting large and unexpected parachute movements, a scale bar for comparison to human height.
(Lower right corner) A compass that shows the changing direction of view as Huygens rotates, along with the relative positions of the sun and Cassini.
(Upper right corner) A clock that shows Universal Time for Jan. 14, 2005 (Universal Time is 7 hours ahead of Pacific Daylight Time). Above the clock, events are listed in mission time, which starts with the deployment of the first of the three parachutes.
Sounds from a left speaker trace Huygens' motion, with tones changing with rotational speed and the tilt of the parachute. There also are clicks that clock the rotational counter, as well as sounds for the probe's heat shield hitting Titan's atmosphere, parachute deployments, heat shield release, jettison of the camera cover and touchdown.

Sounds from a right speaker go with the Descent Imager/Spectral Radiometer activity. There's a continuous tone that represents the strength of Huygens' signal to Cassini. Then there are 13 different chimes - one for each of instrument's 13 different science parts - that keep time with flashing-white-dot exposure counters. During its descent, the Descent Imager/Spectral Radiometer took 3,500 exposures.

http://saturn.jpl.nasa.gov/multimedia/images/videothumbnails/images/IMG002117-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=117)

14MB QT Captioned movie (http://saturn.jpl.nasa.gov/multimedia/videos/movies/pia08118-320-cc.mov)
A View from Huygens - Jan. 14, 2005

This movie was built with data collected during the 147-minute plunge through Titan's thick orange-brown atmosphere to a soft sandy riverbed by the European Space Agency's Huygens Descent Imager/Spectral Radiometer on Jan. 14, 2005,
In 4 minutes and 40 seconds, the movie shows what the probe 'saw' within the few hours of the descent and the landing. On approach, Titan appeared as just a little disk in the sky among the stars, but after landing, the probe's camera resolved little grains of sand millions of times smaller than Titan.

At first, the Huygens camera just saw fog over the distant surface. The fog started to clear only at about 60 kilometers (37 miles) altitude, making it possible to resolve surface features as large as 100 meters (328 feet). Only after landing could the probe's camera resolve the little grains of sand. The movie provides a glimpse of such a huge change of scale.

A music-only version of the video is available at: http://photojournal.jpl.nasa.gov/catalog/PIA08118.

Moogs

2006-05-06, 10:41

The Titan QT sequence reminds me of the 60s acid-trip sci-fi movies, with all the funky sounds and graphics. Logan vs. Montag Part Deux

julesstoop

2006-05-06, 10:43

Higher resolution versions of the movies curiousuburb mentions in his posting can be found on the ESA site. Unfortunately they are in WMV...

http://esamultimedia.esa.int/multimedia/video/Movie_HiRes+Narration_25Apr06.wmv

http://esamultimedia.esa.int/multimedia/video/DISRMovie_25Apr06.wmv

curiousuburb

2006-05-13, 07:56

Sweet updates today...

Titan, rings, and tiny Epimetheus all in one frame

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG002131-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2131)

Stunning Vistas
May 12, 2006 Full-Res: PIA07786 (http://photojournal.jpl.nasa.gov/catalog/PIA07786)

The Cassini spacecraft delivers this stunning vista showing small, battered Epimetheus and smog-enshrouded Titan, with Saturn's A and F rings stretching across the scene.

The prominent dark region visible in the A ring is the Encke Gap, in which the moon Pan and several narrow ringlets reside. Moon-driven features that mark the A ring are easily seen to the left and right of the Encke Gap. The Encke Gap is 325 kilometers (200 miles) wide. Pan is 26 kilometers (16 miles) across.

In an optical illusion, the narrow F ring, outside the A ring, appears to fade across the disk of Titan. A couple of bright clumps can be seen in the F ring.

Epimetheus is 116 kilometers (72 miles) across and giant Titan is 5,150 kilometers (3,200 miles) across.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 28, 2006, at a distance of approximately 667,000 kilometers (415,000 miles) from Epimetheus and 1.8 million kilometers (1.1 million miles) from Titan. The image captures the illuminated side of the rings. The image scale is 4 kilometers (2 miles) per pixel on Epimetheus and 11 kilometers (7 miles) per pixel on Titan.

http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA08176-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2129)

And a view only available from the 'dark side'...

Saturn's Night Colors
May 11, 2006 Full-Res: PIA08176 (http://photojournal.jpl.nasa.gov/catalog/PIA08176)

This rare color view of Saturn's night side shows how the rings dimly illuminate the southern hemisphere, giving it a dull golden glow. Part of the northern dark side is just visible at top -- the illumination it receives being far less than the south.
The unlit side of the rings is shown here. The portion of the rings closest to Cassini is within the dark shadow of Saturn; the bright distant portion is outside the planet's shadow.

A crescent Tethys (1,071 kilometers, or 665 miles across) appears below the rings at left.

Images taken using red, green and blue spectral filters were combined to create this color view. The images were taken with the Cassini spacecraft narrow-angle camera on April 2, 2006, at a distance of approximately 3.8 million kilometers (2.4 million miles) from Saturn and 3.5 kilometers (2.2 million miles) from Tethys. The image scale is about 23 kilometers (14 miles) per pixel on Saturn.

There are also some new Titan dune shots up.

Brad

2006-05-13, 08:03

Beautiful.

Keep 'em coming, 'burb. :)

curiousuburb

2006-05-16, 20:43

Death Star At Saturn... (with movie links)http://www.davidlegatt.com/images/albums/userpics/10002/1596_4365_0.gif (http://ciclops.org/view.php?id=1596&flash=1)

curiousuburb

2006-06-05, 15:11

Update:

Janus and Prometheus from below the Ring plane.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08192-br402.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2151)

So Close . . .
June 5, 2006
Full-Res: PIA08192 (http://photojournal.jpl.nasa.gov/catalog/PIA08192)

Saturn's moons Janus and Prometheus look close enough to touch in this stunningly detailed view.

From just beneath the ringplane, Cassini stares at Janus (181 kilometers, or 113 miles across) on the near side of the rings and Prometheus (102 kilometers, or 63 miles across) on the far side. The image shows that Prometheus is more elongated than Janus.

The view takes in the Cassini Division (4,800 kilometers, or 2,980 miles wide), from its outer edge to about halfway across its width.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 29, 2006 at a distance of approximately 218,000 kilometers (135,000 miles) from Janus and 379,000 kilometers (236,000 miles) from Prometheus. Image scale is about 1 kilometer (0.6 mile) per pixel on Janus and 2 kilometers (1 mile) per pixel on Prometheus. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.

curiousuburb

2006-06-09, 08:44

Moons and Rings update:

Rhea occults Enceladus... (check out the Rhea-shine on Enceladus)

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08180-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2137)

Now You See Me...
May 18, 2006 Full-Res: PIA08180 (http://photojournal.jpl.nasa.gov/catalog/PIA08180)

Enceladus briefly passes behind the crescent of Rhea in these images, which are part of a "mutual event" sequence taken by Cassini. These sequences help scientists refine our understanding of the orbits of Saturn's moons.

The images were taken one minute apart as smaller Enceladus (505 kilometers, or 314 miles across) darted behind Rhea (1,528 kilometers, or 949 miles across) as seen from the Cassini spacecraft's point of view.

The images were taken in visible light with the Cassini spacecraft narrow-angle camera on April 14, 2006, at a distance of approximately 3.4 million kilometers (2.1 million miles) from Rhea and 4.1 million kilometers (2.5 million miles) from Enceladus. The image scale is 20 kilometers (13 miles) per pixel on Rhea and 24 kilometers (15 miles) per pixel on Enceladus.

Two more of occultations between the Rings, Moons, and Saturn.

The Dark Side of Saturn (with Enceladus)
http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08195-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2154)

Dark Side of Saturn's Moon
June 8, 2006 Full-Res: PIA08195 (http://photojournal.jpl.nasa.gov/catalog/PIA08195)

Cassini stares toward the night side of Saturn, seen here on the right, as the active icy moon Enceladus glides past.
The moon's now famous icy plumes spew out of the south polar region (see Fountains of Enceladus), providing a fresh supply of material for Saturn's E ring.

Enceladus is 505 kilometers (314 miles) across. Saturn's shadow stretches over the rings above the crescent moon.

The image was acquired in visible light with the Cassini spacecraft narrow-angle camera on May 4, 2006 at a distance of approximately 2.1 million kilometers (1.3 million miles) from Enceladus and 2.3 million kilometers (1.5 million miles) from Saturn. The image was taken at a Sun-Enceladus-spacecraft, or phase, angle of 159 degrees. Image scale is 13 kilometers (8 miles) per pixel on Enceladus.

If you look closely at the larger image (below), you can see the Fountains of Enceladus emitting particles from the south pole!

http://photojournal.jpl.nasa.gov/jpeg/PIA08195.jpg

----

And Mimas peeking out from behind the Rings

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA08194-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2153)

Hiding a Moon
June 7, 2006 Full-Res: PIA08194 (http://photojournal.jpl.nasa.gov/catalog/PIA08194)

The dim, unlit side of Saturn's rings hides a secret in this view. Shy Mimas (397 kilometers, or 247 miles across) can be seen peeking out from behind the rings below center.
The bright features in this scene, including the F ring along the rings' periphery, are regions where tiny, dust-sized particles scatter light toward the camera. This phenomenon is often seen at high phase angles -- that is, Sun-ring-spacecraft angles -- approaching 180 degrees.

The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on May 3, 2006 at a distance of approximately 2.2 million kilometers (1.4 million miles) from Mimas and phase angle of 161 degrees. Image scale is 13 kilometers (8 miles) per pixel.

curiousuburb

2006-06-10, 07:50

Titan gets the Rings occluding treatment

http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA08196-br500.jpg
(http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2156)

A Sight to Behold
June 9, 2006 Full-Res: PIA08196 (http://photojournal.jpl.nasa.gov/catalog/PIA08196)

Cassini's "eyes" -- its powerful imaging cameras -- bear witness to the majestic and spectacular sights of the Saturn system, as this views attests. Here, the probe gazes upon Titan (5,150 kilometers, or 3,200 miles across) in the distance beyond Saturn and its dark and graceful rings.
This view was taken from above the ringplane and looks toward the unlit side of the rings.

The image was taken using a spectral filter sensitive to wavelengths of infrared light centered at 938 nanometers. The image was obtained using the Cassini spacecraft narrow-angle camera on May 10, 2006 at a distance of approximately 2.9 million kilometers (1.8 million miles) from Saturn and 4.1 million kilometers (2.6 million miles) from Titan. The image was taken at a Sun-Saturn-spacecraft, or phase, angle of 149 degrees. Image scale is 17 kilometers (11 miles) per pixel on Saturn.

People forget how thin the ringplane can appear (and this isn't the thinnest-appearance shot from Cassini), and that Titan's atmosphere is quite hazy.

curiousuburb

2006-06-13, 08:01

Enceladus shows its tail again

http://photojournal.jpl.nasa.gov/jpeg/PIA08197.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2157)

A Moon's Telltale Tail
June 12, 2006 Full-Res: PIA08197 (http://photojournal.jpl.nasa.gov/catalog/PIA08197)

The plumes of Enceladus continue to gush icy particles into Saturn orbit, making this little moon one of a select group of geologically active bodies in the solar system.

Enceladus (505 kilometers, or 314 miles across) is seen here against the night side of Saturn. The extended exposure time used to image the plumes also makes the southern hemisphere, illuminated by ring-shine, appear bright.

The image was acquired in visible light with the Cassini spacecraft narrow-angle camera on May 4, 2006 at a distance of approximately 2.1 million kilometers (1.3 million miles) from Enceladus and 2.3 million kilometers (1.5 million miles) from Saturn. The image was taken at a Sun-Enceladus-spacecraft, or phase, angle of 159 degrees. Image scale is 13 kilometers (8 miles) per pixel on Enceladus.

curiousuburb

2006-06-19, 07:17

NASA has posted an enhanced version of the Enceladus plume image

http://photojournal.jpl.nasa.gov/jpeg/PIA08199.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2159)

Scattered Ice, Scattered Light
June 14, 2006

An enhanced close-up view shows at least two distinct jets spraying a mist of fine particles from the south polar region of Enceladus. The particles in the plume scatter sunlight most effectively at high Sun-Enceladus-spacecraft angles, or phase angles, making the plumes appear bright. This image shows the night side of Saturn and the active moon against dark sky. Enceladus is 505 kilometers (314 miles) across.

Some artifacts due to image compression and cosmic rays striking the camera's detector remain as noise in the image.

The image was acquired in polarized green light with the Cassini spacecraft narrow-angle camera on May 4, 2006 at a distance of approximately 2.1 million kilometers (1.3 million miles) from Enceladus and 2.3 million kilometers (1.4 million miles) from Saturn. The image was taken at a Sun-Enceladus-spacecraft, or phase, angle of 159 degrees. Image scale is 13 kilometers (8 miles) per pixel.

As well as a nice IR image of the Rings and Dione

http://photojournal.jpl.nasa.gov/jpeg/PIA08201.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2163)

Saturn's Night Lights
June 16, 2006

The dark side of the ringplane glows with scattered light, including the luminous F ring, which shines like a rope of brilliant neon. Below, Dione (1,126 kilometers, or 700 miles across) presents an exquisitely thin crescent.
The image was taken using a spectral filter sensitive to wavelengths of infrared light centered at 930 nanometers. The image was acquired with the Cassini spacecraft narrow-angle camera on May 3, 2006 at a distance of approximately 1.8 million kilometers (1.1 million miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 160 degrees. Image scale is 11 kilometers (7 miles) per pixel.

curiousuburb

2006-06-21, 09:32

Rhea and Dione do the moonshine/occultation thing

http://photojournal.jpl.nasa.gov/jpeg/PIA08203.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2165)

Uncovering Rhea
June 20, 2006 Full-Res: PIA08203
(http://photojournal.jpl.nasa.gov/catalog/PIA08203)
Two Saturnian moons meet in the sky. Dione departs after crossing the face of Rhea for several minutes.

Dione (1,126 kilometers, or 700 miles across), at right, has a notably smoother-looking surface than Rhea (1,528 kilometers, or 949 miles across), suggesting the former has been modified more recently.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 14, 2006 at a distance of approximately 2.7 million kilometers (1.7 million miles) from Dione and 3.1 million kilometers (1.9 million miles) from Rhea. The Sun-moon-spacecraft, or phase, angle is about 134 degrees on both moons. Image scale is 16 kilometers (10 miles) per pixel on Dione and 18 kilometers (11 miles) per pixel on Rhea.

Brad

2006-06-21, 10:56

Beautiful.

Again, thanks for keeping us updated. :)

curiousuburb

2006-06-22, 06:27

Moon movies from Cassini!

In addition to the usual impressive image updates, the Cassini-Huygens project gnomes have released a bunch of new movie clips.

Some are .GIF, some are .MOV, and some are .MPEG format files, each compiled from camera images of various moons interacting with each other, or the Rings, or Saturn itself. In some cases, you can see some of the rotation, in others the spacecraft motion or orbital mechanics seem to make this more difficult.

Click images for alternate movie formats or source pages.

Silent Spheres
http://saturn.jpl.nasa.gov/multimedia/videos/movies/PIA07804_full_movie.gif
(http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=120)
In a silent orbital ballet, Saturn's crater-covered moon Rhea slips between the moons Mimas and Enceladus. The dark sides of Enceladus (bottom) and Mimas (top) are dimly illuminated by reflected light from Saturn.

Rhea is 1,528 kilometers (949 miles) across, Mimas is 397 kilometers (247 miles) across, and Enceladus is 505 kilometers (314 miles) across.

The movie was created using 59 clear-filter images taken over a period of about 40 minutes. The images were acquired by the Cassini spacecraft narrow-angle camera on Jan. 27, 2006, at a mean distance of approximately 3 million kilometers (1.9 million miles) from Rhea, 3.5 million kilometers (2.2 million miles) from Mimas, and 3.7 million kilometers (2.3 million miles) from Enceladus. The image scale is approximately 18 kilometers (11 miles) per pixel on Rhea, 21 kilometers (13 miles) per pixel on Mimas, and 22 kilometers (14 miles) per pixel on Enceladus.

Staying with Epimetheus
http://saturn.jpl.nasa.gov/multimedia/videos/movies/PIA07802_full_movie.gif (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=119)
Three of Saturn's moons swim past in this movie sequence of images from the Cassini spacecraft. These sequences, called mutual events, are useful for refining scientists' understanding the orbits of the moons.

The movie follows Epimetheus (116 kilometers, or 72 miles across) as it passes in front of Titan (5,150 kilometers, or 3,200 miles across) and then Dione (1,126 kilometers, or 700 miles across).

The faint object that appears at the left, below the ringplane, halfway through the movie is a background star.

The movie was created using 24 clear-filter images taken over a period of about 40 minutes. The images were acquired by the Cassini spacecraft narrow-angle camera on Jan. 5, 2006, at a mean distance of approximately 3 million kilometers (1.9 million miles) from Epimetheus. The image scale is approximately 18 kilometers (11 miles) per pixel on Epimetheus, 25 kilometers (16 miles) per pixel on Titan and 20 kilometers (12 miles) per pixel on Dione.

Cruising with Pan
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Saturn's small, walnut-shaped moon, Pan, embedded in the planet's rings, coasts along in this movie clip from the Cassini spacecraft.

The movie begins with Pan (26 kilometers, or 16 miles across) and the rings against the night side of Saturn. Cassini stays fixed on Pan as the moon heads toward the outside edge, or ansa, of the Encke Gap (325 kilometers, or 200 miles wide) in which it orbits. Saturn's dark shadow is seen stretching across the middle of the ringplane. Midway through the sequence, the far side of the rings emerges from behind the planet, but eventually is completely darkened by Saturn's shadow.

The small, bright moving object that appears from the lower left, near the end of the sequence, is a bright background star.

The 40 images in this movie were taken in visible light with the Cassini spacecraft narrow-angle camera on April 29, 2006, at a distance of approximately 209,000 kilometers (130,000 miles) from Pan. The image scale is approximately 1 kilometer (0.6 miles) per pixel.

Three Moons Meet
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Saturn's moons Janus and Epimetheus are captured swinging around Saturn's rings and past Dione in this movie sequence from the Cassini spacecraft.

The spacecraft repeatedly imaged the two moons just as they were about to round the outside edge of the rings, which were out of view to the left. Janus and Epimetheus orbit Saturn at nearly the same distance and velocity, although (as seen here) Janus is several tens of thousands of kilometers ahead of Epimetheus and farther from Cassini. Dione is actually quite far in the background compared to the small moons.

At the beginning of the movie, Epimetheus (116 kilometers, or 72 miles across) is at the left, Janus (181 kilometers, or 113 miles across) is at the center, and Dione (1,126 kilometers, or 700 miles across) is at the right.

The movie was created using 18 clear-filter images taken over a period of about 30 minutes. The images were acquired by the Cassini spacecraft narrow-angle camera on Dec. 30, 2005, at a mean distance of approximately 2.3 million kilometers (1.4 million miles) from Janus and 2.3 million kilometers (1.4 million miles) from Epimetheus. The image scale is approximately 14 kilometers (9 miles) per pixel on Janus and Epimetheus, and 16 kilometers (10 miles) per pixel on Dione.

Rhea Eclipses Dione
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Two crescent moons dance around Saturn as far-off Dione slips behind its sibling moon Rhea. From Cassini's perspective, Rhea's bulk (1,528 kilometers, 949 miles wide) completely covered her smaller celestial companion Dione (1,126 kilometers, 700 miles wide) for about three minutes before the smaller moon re-emerged.

The images used for this movie sequence were taken over approximately 27 minutes as Cassini stared at Rhea. The images were aligned to keep Rhea close to the center of the scene. Additional frames were inserted among the 38 original Cassini images in order to smooth the appearance of Dione's movement -- a scheme called interpolation. For another eclipse movie showing these two moons, see PIA06199 (http://photojournal.jpl.nasa.gov/catalog/PIA06199).

The clear-filter images in this movie were acquired with the Cassini narrow-angle camera on Dec. 5, 2005, from a distance of 2.4 million kilometers (1.5 million miles) from Rhea and 2.7 million kilometers (1.7 million miles) from Dione. Image scale is about 14 kilometers (9 miles) per pixel on Rhea and 16 kilometers (10 miles) per pixel on Dione.

Rhea Occults Saturn
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The slim crescent of the moon Rhea glides silently onto the featureless, golden face of Saturn in this mesmerizing color movie. In an interplay of contrast and shadow, the moon goes dark against the planet, and then its crescent suddenly brightens as it slips in front of Saturn's night side.

This view looks down onto the unlit side of Saturn's rings, which cast soft, linear shadows onto the planet's northern hemisphere.

The movie was created using 60 images taken using red, green and blue spectral filters over a period of about 45 minutes.

The images were acquired by the Cassini spacecraft narrow-angle camera on March 21, 2006, at a distance of approximately 221,000 kilometers (137,000 miles) from Rhea. The image scale is approximately 13 kilometers (8 miles) per pixel.

And although today's image update doesn't move, it is impressive nonetheless...

Enceladus and Titan
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A Tale of Two Moons
June 21, 2006 Full-Res: PIA07787 (http://photojournal.jpl.nasa.gov/catalog/PIA07787)

Many denizens of the Saturn system wear a uniformly gray mantle of darkened ice, but not these two moons. The brightest body in the solar system, Enceladus, is contrasted here against Titan's smoggy, golden murk.

Ironically, what these two moons hold in common gives rise to their stark contrasting colors. Both bodies are, to varying degrees, geologically active. For Enceladus, its southern polar vents emit a spray of icy particles that coats the small moon, giving it a clean, white veneer. On Titan, yet undefined processes are supplying the atmosphere with methane and other chemicals that are broken down by sunlight. These chemicals are creating the thick yellow-orange haze that is spread through the atmosphere and, over geologic time, falls and coats the surface.

The thin, bluish haze along Titan's limb is caused when sunlight is scattered by haze particles roughly the same size as the wavelength of blue light, or around 400 nanometers.

Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained on Feb. 5, 2006, using the Cassini spacecraft narrow-angle camera at a distance of 4.1 million kilometers (2.5 million miles) from Enceladus and 5.3 million kilometers (3.3 miles) from Titan. Resolution in the original images was 25 kilometers (16 miles) per pixel on Enceladus and 32 kilometers (20 miles) per pixel on Titan. The view has been magnified by a factor of two.

curiousuburb

2006-07-02, 08:23

Glorious new image of Titan, the Rings, and Janus.
Nice atmospheric detail on Titan.

http://photojournal.jpl.nasa.gov/jpeg/PIA08211.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2185)

Ring of Light
June 30, 2006 Full-Res: PIA08211 (http://photojournal.jpl.nasa.gov/catalog/PIA08211)

Dazzling Titan glows with a 360-degree sunset as light scatters through its very extended atmosphere. Some structure is visible in the hazes of the northern polar hood.

To the left is Janus (181 kilometers, or 113 miles across), far off on the opposite side of the ringplane. The rings show their unlit side to Cassini, as the spacecraft viewed them from slightly above the ringplane.

A world with strikingly Earth-like physical processes, frigid Titan is Saturn's largest natural satellite, at 5,150 kilometers (3,200 miles) across. Titan's image is saturated at the 5 o'clock position.

The view was acquired in visible light with the Cassini spacecraft narrow-angle camera on June 2, 2006 at a distance of approximately 2.3 million kilometers (1.5 million miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 163 degrees. Cassini was 3.7 million kilometers (2.3 million miles) from Janus. Image scale is 14 kilometers (9 miles) per pixel on Titan and 22 kilometers (14 miles) on Janus.

Those who are curious can now get a podcast of Cassini highlights.
(http://www.jpl.nasa.gov/multimedia/podcast/cassini-20060627/)

julesstoop

2006-07-02, 09:58

It's actually a podcast about everything JPL. So it has episodes on many different (interplanetary) mission. Interesting stuff.

curiousuburb

2006-07-12, 10:05

Enceladus plumes, and Rings, and Moons... beautiful new images from Saturn

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08216-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2192)

The Moons Are the Stars
July 7, 2006 Full-Res: PIA08216 (http://photojournal.jpl.nasa.gov/catalog/PIA08216)

The real jewels of Saturn are arguably its stunning collection of icy moons. Seen here with the unlit side of the rings are Titan (5,150 kilometers, or 3,200 miles across at right), Tethys (1,071 kilometers, or 665 miles across at left) and Enceladus (505 kilometers, or 314 miles across at center) with its fountain-like geysers.

The faint, vertical banding in the image is due to "noise" in the spacecraft electronics. This noise is difficult to remove from an image that has a very wide dynamic range--i.e., a wide range of brightness levels--as in the difference between gleaming Titan and the faint plumes of Enceladus.

Additionally, a reflection of Titan's light within the camera optics is likely responsible for the faint secondary image of Titan's limb to the left of the giant moon.

The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on June 10, 2006 at a distance of approximately 3.9 million kilometers (2.4 million miles) from Enceladus, 5.3 million kilometers (3.3 million miles) from Titan and 4.4 million kilometers (2.7 million miles) from Tethys. The Sun-Enceladus-spacecraft, or phase, angle is 160 degrees on Enceladus. Image scale is 23 kilometers (14 miles) per pixel on Enceladus, 32 kilometers (20 miles) per pixel on Titan and 26 kilometers (16 miles) per pixel on Tethys.

http://photojournal.jpl.nasa.gov/jpeg/PIA08217.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2193)

Softly Glowing Scene
July 10, 2006 Full-Res: PIA08217 (http://photojournal.jpl.nasa.gov/catalog/PIA08217)

Enceladus blasts its icy spray into space in this unlit-side ring view that also features a tiny sliver of Rhea.

The south polar region of Rhea (1,528 kilometers, or 949 miles across) peeks out from beneath the rings to the right of Enceladus (505 kilometers, or 314 miles across).

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 9, 2006 at a distance of approximately 3.9 million kilometers (2.4 million miles) from Enceladus and 4.6 million kilometers (2.9 million miles) from Rhea. The Sun-Enceladus-spacecraft, or phase, angle is 161 degrees. Image scale is 23 kilometers (14 miles) per pixel on Enceladus.

http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA08218-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2194)

A Captivating Vision
July 11, 2006 Full-Res: PIA08218 (http://photojournal.jpl.nasa.gov/catalog/PIA08218)

Cassini captured this arresting view of Saturn just before Epimetheus crossed into the blinding glare of the planet's sunlit crescent and was lost.

As it orbits Saturn, Epimetheus (116 kilometers, or 72 miles across) hugs the outside edge of the narrow F ring, beyond the orbit of Pandora. The F ring is the brightest ring feature seen here. Saturn's southern hemisphere is softly lit by sunlight reflected off the rings.

A less obvious feature in this view is the planet's shadow, which begins to darken the inner regions of the rings at left. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 9, 2006 at a distance of approximately 4 million kilometers (2.5 million miles) from Epimetheus and 4.1 million kilometers (2.5 million miles) from Saturn. The Sun-Epimetheus-spacecraft, or phase, angle is 161 degrees. Image scale is 25 kilometers (16 miles) per pixel on Saturn.

AWR

2006-07-12, 10:48

Interesting and beautiful shots. Thanks for the effort, curiousuburb. :)

curiousuburb

2006-07-15, 12:42

Shine on you crazy spheres.

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA08220-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2196)

Light from Many Paths
July 13, 2006 Full-Res: PIA08220 (http://photojournal.jpl.nasa.gov/catalog/PIA08220)

The unlit side of the rings glows with scattered sunlight as two moons circle giant Saturn. The light reaching Cassini in this view has traveled many paths before being captured.

At left, Mimas (397 kilometers, or 247 miles across) presents its dark side. Enceladus (505 kilometers, or 314 miles across), on the far side of the rings, is lit by "Saturnshine," or reflected sunlight coming from the planet. Saturn, in turn, is faintly lit in the south by light reflecting off the rings.

Saturn's shadow darkens the rings, tapering off toward the left side of this view.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 11, 2006 at a distance of approximately 3.9 million kilometers (2.5 million miles) from Mimas, 4.3 kilometers (2.7 miles) from Enceladus and 4.1 million kilometers (2.6 miles) from Saturn. Image scale is 25 kilometers (16 miles) per pixel on Saturn.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08219-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2195)

Rings Occulting Titan
July 12, 2006 Full-Res: PIA08219 (http://photojournal.jpl.nasa.gov/catalog/PIA08219)

Titan shines beyond the rings like a brilliant ring of fire, its light gleaming here and there through the gaps in Saturn's magnificent plane of ice.

Titan (5,150 kilometers, or 3,200 miles across) is surrounded by a thick photochemical haze which scatters the Sun's light.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 11, 2006 at a distance of approximately 5.3 million kilometers (3.3 million miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 158 degrees. Image scale is 32 kilometers (20 miles) per pixel on Titan.

http://photojournal.jpl.nasa.gov/jpeg/PIA08221.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2197)

Titan's Kiss
July 14, 2006 Full-Res: PIA08221 (http://photojournal.jpl.nasa.gov/catalog/PIA08221)

Saturn's two largest moons meet in the sky in a rare embrace. Smog-enshrouded Titan (5,150 kilometers, or 3,200 miles across) glows to the left of airless Rhea (1,528 kilometers, or 949 miles across).

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 11, 2006 at a distance of approximately 3.6 million kilometers (2.2 million miles) from Rhea and 5.3 million kilometers (3.3 million miles) from Titan. The Sun-Rhea-spacecraft, or phase, angle is 157 degrees on Rhea. Image scale is 22 kilometers (13 miles) per pixel on Rhea and 32 kilometers (20 miles) per pixel on Titan.

curiousuburb

2006-07-23, 08:12

Moons and Rings update:

http://photojournal.jpl.nasa.gov/jpeg/PIA08224.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2206)

Planetglow
July 19, 2006 Full-Res: PIA08224 (http://photojournal.jpl.nasa.gov/catalog/PIA08224)

Two frigid moons, Rhea and Enceladus, shine in reflected light from Saturn. In such low light and at great distance, Rhea's cratered surface looks deceptively smooth. Light from the distant Sun creates the bright crescent on each moon and scatters off the icy spray above the south pole of Enceladus.

Rhea is 1,528 kilometers (949 miles) across, and Enceladus is 505 kilometers (314 miles) across.

The image background appears generally brighter across its center due to the diffuse E ring, which is created by the jets of material from Enceladus.

The faint vertical banding in the image is due to "noise" in the spacecraft electronics.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 13, 2006 at a distance of approximately 4.1 million kilometers (2.5 million miles) from Enceladus and 4.5 million kilometers (2.8 million miles) from Rhea. The Sun-Enceladus-spacecraft, or phase, angle is 159 degrees. Image scale is 24 kilometers (15 miles) per pixel on Enceladus and 27 kilometers (17 miles) per pixel on Rhea.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08226-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2211)

Boosting the Signal
July 21, 2006 Full-Res: PIA08226 (http://photojournal.jpl.nasa.gov/catalog/PIA08226)

The ice jets of Enceladus send particles streaming into space hundreds of kilometers above the south pole of this spectacularly active moon. Some of the particles escape to form the diffuse E ring around Saturn.

This color-coded image was processed to enhance faint signals, making the contours and extent of the fainter, larger-scale component of the plume easier to see.

The bright strip behind and above Enceladus (505 kilometers, 314 miles across) is the E ring, in which this intriguing body resides. The small round object at far left is a background star.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 24, 2006 at a distance of approximately 1.9 million kilometers (1.2 million miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 162 degrees. Image scale is 11 kilometers (7 miles) per pixel.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08225-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2210)

Darkened Moons, Searing F Ring
July 20, 2006 Full-Res: PIA08225 (http://photojournal.jpl.nasa.gov/catalog/PIA08225)

Two ring moons chase each other as their larger sibling looks on.This view shows Tethys at lower left, along with perpetually mingling Epimetheus at left of center, and Janus at center.

Tethys is 1,071 kilometers (665 miles) across; Epimetheus is 116 kilometers (72 miles) across; and Janus is 181 kilometers (113 miles) across.

In the background, the faint G ring and brilliant F ring bound the location where Cassini entered Saturn orbit. The spacecraft passed between these two rings upon arrival in mid-2004.

Near the right side of the image, a couple of ringlets within the Encke gap glow faintly.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 15, 2006 at a distance of approximately 3.9 million kilometers (2.4 million miles) from Janus, 4 million kilometers (2.5 million miles) from Epimetheus, and 3.7 million kilometers (2.3 million miles) from Tethys. Image scale is 24 kilometers (15 miles) per pixel on Janus and Epimetheus and 22 kilometers (14 miles) per pixel on Tethys.

Meanwhile, some new radar from Titan is up.

http://saturn.jpl.nasa.gov/multimedia/images/non-press/images/IMG002207.jpg (http://saturn.jpl.nasa.gov/news/events/titan20060722/index.cfm)

Cassini's Search for Lakes Continues

After revealing a land of mountains and river channels near Titan's equator in April, Cassini's radar will illuminate the high northern reaches of Titan during the next flyby on July 21, 2006 (July 22 UTC). In winter's shadow since the arrival of Cassini in 2004, Titan's northern terrain could harbor methane lakes, which shrink in summer and expand in winter.
http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG002127-th150.jpg (http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG002127.jpg)
The Cassini spacecraft's Titan Radar Mapper instrument imaged this area atop Xanadu, the bright area of Titan, on April 30, 2006. The darkest areas could contain liquids, which tend to reflect the radar beam away from Cassini in the absence of winds, making the area appear quite dark.

http://saturn.jpl.nasa.gov/multimedia/images/non-press/images/IMG002209-br402.jpg (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=675)

Cassini Reveals Titan's Xanadu Region To Be an Earth-like Land
July 19, 2006
(Source: NASA/JPL)

Panning west to east, the geologic features include river channels, mountains and hills, a crater and possible lakes.
http://saturn.jpl.nasa.gov/multimedia/images/videothumbnails/images/IMG002205-th200.jpg+ Play QuickTime Movie (6.7 MB) (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=124)

New radar images from NASA's Cassini spacecraft revealed geological features similar to Earth on Xanadu, an Australia-sized, bright region on Saturn's moon Titan.

These radar images, from a strip more than 4,500 kilometers (2,796 miles) long, show Xanadu is surrounded by darker terrain, reminiscent of a free-standing landmass. At the region's western edge, dark sand dunes give way to land cut by river networks, hills and valleys. These narrow river networks flow onto darker areas, which may be lakes. A crater formed by the impact of an asteroid or by water volcanism is also visible. More channels snake through the eastern part of Xanadu, ending on a dark plain where dunes, abundant elsewhere, seem absent. Appalachian-sized mountains crisscross the region.

"We could only speculate about the nature of this mysterious bright country, too far from us for details to be revealed by Earth-based and space-based telescopes. Now, under Cassini's powerful radar eyes, facts are replacing speculation," said Dr. Jonathan Lunine, Cassini interdisciplinary scientist at the University of Arizona, Tucson. "Surprisingly, this cold, faraway region has geological features remarkably like Earth."

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG002203-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2203) Click image for more

This image of Titan was acquired on April 30, 2006, by Cassini's radar instrument in synthetic-aperture mode over the continent-sized region called Xanadu.

Titan is a place of twilight, dimmed by a haze of hydrocarbons surrounding it. Cassini's radar instrument can see through the haze by bouncing radio signals off the surface and timing their return. In the radar images, bright regions indicate rough or scattering material, while a dark region might be smoother or more absorbing material, possibly liquid.

Xanadu was first discovered by NASA's Hubble Space Telescope in 1994 as a striking bright spot seen in infrared imaging. When Cassini's radar system viewed Xanadu on April 30, 2006, it found a surface modified by winds, rain, and the flow of liquids. At Titan's frigid temperatures, the liquid cannot be water; it is almost certainly methane or ethane.

"Although Titan gets far less sunlight and is much smaller and colder than Earth, Xanadu is no longer just a mere bright spot, but a land where rivers flow down to a sunless sea," Lunine said. Observations by the European Space Agency's Huygens probe, which Cassini carried to Titan, and by NASA's Voyager spacecraft strongly hint that both methane rain and dark orange hydrocarbon solids fall like soot from the moon's dark skies.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08604-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2208) Click image for more

A network of river channels is located atop Xanadu.

On Xanadu, liquid methane might fall as rain or trickle from springs. Rivers of methane might carve the channels and carry off grains of material to accumulate as sand dunes elsewhere on Titan.

"This land is heavily tortured, convoluted and filled with hills and mountains," said Steve Wall, the Cassini radar team's deputy leader at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "There appear to be faults, deeply cut channels and valleys. Also, it appears to be the only vast area not covered by organic dirt. Xanadu has been washed clean. What is left underneath looks like very porous water ice, maybe filled with caverns."

"In the 1980s, it took the shuttle imaging radar to discover subsurface rivers in the Sahara. Similarly, if it hadn't been for the Cassini radar, we would have missed all of this. We have a newly discovered continent to explore," Wall said.

Cassini will view Titan again on Saturday, July 22, exploring the high northern latitudes. In the next two years the orbiter will fly by Titan 29 times, nearly twice as many encounters as in the first half of Cassini's four-year prime mission. Twelve of the planned flybys will use radar.

julesstoop

2006-07-25, 17:36

Strong evidence for lakes on Titan

From NASA (http://photojournal.jpl.nasa.gov/catalog/PIA08630)

The Cassini spacecraft, using its radar system, has discovered very strong evidence for hydrocarbon lakes on Titan. Dark patches, which resemble terrestrial lakes, seem to be sprinkled all over the high latitudes surrounding Titan's north pole.

Scientists have speculated that liquid methane or ethane might form lakes on Titan, particularly near the somewhat colder polar regions. In the images, a variety of dark patches, some with channels leading in or out of them, appear. The channels have a shape that strongly implies they were carved by liquid. Some of the dark patches and connecting channels are completely black, that is, they reflect back essentially no radar signal, and hence must be extremely smooth. In some cases rims can be seen around the dark patches, suggesting deposits that might form as liquid evaporates. The abundant methane in Titan's atmosphere is stable as a liquid under Titan conditions, as is its abundant chemical product, ethane, but liquid water is not. For all these reasons, scientists interpret the dark areas as lakes of liquid methane or ethane, making Titan the only body in the solar system besides Earth known to possess lakes. Because such lakes may wax and wane over time, and winds may alter the roughness of their surfaces. Repeat coverage of these areas should test whether indeed these are bodies of liquid.

These two radar images were acquired by the Cassini radar instrument in synthetic aperture mode on July 21, 2006. The top image centered near 80 degrees north, 92 degrees west measures about 420 kilometers by 150 kilometers (260 miles by 93 miles). The lower image centered near 78 degrees north, 18 degrees west measures about 475 kilometers by 150 kilometers (295 miles by 93 miles). Smallest details in this image are about 500 meters (1,640 feet) across.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

http://photojournal.jpl.nasa.gov/jpegMod/PIA08630_modest.jpg

This is something quite revolutionary. They would be the first bodies of liquid found on the surface of a planet other than dear mother Earth.

curiousuburb

2006-08-09, 15:59

Rings and Moons update:

Rings and Rhea
http://photojournal.jpl.nasa.gov/jpeg/PIA08239.jpg
Coy Rhea
August 9, 2006 Full-Res: PIA08239 (http://photojournal.jpl.nasa.gov/catalog/PIA08239)

The rings cannot hide the ragged, icy crescent of Rhea, here imaged in color by the Cassini spacecraft. The second-largest moon of Saturn shines brightly through gaps in the rings.

Rhea (1,528 kilometers, or 949 miles across) lies beyond the dim, unlit side of the rings. A diffuse clump of material lies in the F ring, on the side nearest to Cassini.

Images taken using red, green and blue spectral filters were combined to create this natural color view, which approximates the scene as it might appear to human eyes. The view was acquired with the Cassini spacecraft narrow-angle camera on July 1, 2006 at a distance of approximately 1.2 million kilometers (700,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 118 degrees. Image scale is 7 kilometers (4 miles) per pixel.

Rhea / Enceladus Occultation Redux
http://photojournal.jpl.nasa.gov/jpeg/PIA08237.jpg
Rhea Releases Enceladus
August 7, 2006 Full-Res: PIA08237 (http://photojournal.jpl.nasa.gov/catalog/PIA08237)

Two slim crescents smile toward the Cassini spacecraft following an occultation event.

Taken only five minutes after Enceladus (505 kilometers, or 314 miles across) first approached the limb of Rhea (1,528 kilometers, or 949 miles across), this view shows the bright little moon emerging from behind the larger moon's crescent. (See Enceladus Approaches for the earlier view.)

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 4, 2006 at a distance of approximately 1.4 million kilometers (800,000 miles) from Rhea and 1.9 million kilometers (1.2 million miles) from Enceladus. The view was obtained at a Sun-moon-spacecraft, or phase, angle of about 142 degrees relative to both moons. Image scale is 8 kilometers (5 miles) per pixel on Rhea and 11 kilometers (7 miles) on Enceladus.

Hyperion in False Colour
http://photojournal.jpl.nasa.gov/jpegMod/PIA08236_modest.jpg
Eroded Moon
August 4, 2006 Full-Res: PIA08236 (http://photojournal.jpl.nasa.gov/catalog/PIA08236)

This extreme false-color view of Hyperion shows color variation across the impact-blasted surface of the tumbling moon.

To create this false-color view, ultraviolet, green and infrared images were combined into a single picture that isolates and maps regional color differences. This "color map" was then superposed over a clear-filter image that preserves the relative brightness across the body.

The combination of the color map and brightness image shows how colors vary across Hyperion's surface in relation to geologic features. The origin of the color differences is not yet understood, but may be caused by subtle differences in the surface composition or the sizes of grains making up the icy surface material on Hyperion (280 kilometers, or 174 miles across).

The images used to create this view were acquired using the Cassini spacecraft narrow-angle camera on June 28, 2006 at a distance of approximately 294,000 kilometers (183,000 miles) from Hyperion. Image scale is 2 kilometers (1 mile) per pixel.

Saturn and Rigel
http://photojournal.jpl.nasa.gov/jpeg/PIA08238.jpg
Cassini: the Profiler
August 8, 2006 Full-Res: PIA08238 (http://photojournal.jpl.nasa.gov/catalog/PIA08238)

The Cassini spacecraft continues to profile the haze structure and opacity in Saturn's upper atmosphere with images like this, which captures Rigel, a star in Orion whose brightness is well-known, as it passes behind the planet.

The extent to which the star's light is dimmed tells scientists about the sizes and amounts of the molecules and tiny particles that make up the atmospheric hazes.

The image was taken in visible red light with the Cassini spacecraft narrow-angle camera on June 30, 2004 at a distance of approximately 446,000 kilometers (277,000 miles) from Saturn. Image scale is 3 kilometers (2 miles) per pixel.

Titan, Enceladus, and the Rings
http://photojournal.jpl.nasa.gov/jpegMod/PIA08235_modest.jpg
Candle in the Dark
August 3, 2006 Full-Res: PIA08235 (http://photojournal.jpl.nasa.gov/catalog/PIA08235)

Saturn's rings cut across an eerie scene that is ruled by Titan's luminous crescent and globe-encircling haze, broken by the small moon Enceladus, whose icy jets are dimly visible at its south pole. North is up.

The scattered light around planet-sized Titan (5,150 kilometers, or 3,200 miles across) makes the moon's solid surface visible in silhouette. Enceladus (505 kilometers, or 314 miles across) enjoys far clearer skies than its giant sibling moon.

This view shows the unlit side of Saturn's rings.

The image was taken in visible red light with the Cassini spacecraft narrow-angle camera on June 10, 2006 at a distance of approximately 3.9 million kilometers (2.4 million miles) from Enceladus and 5.3 million kilometers (3.3 million miles) from Titan. The view was obtained at a Sun-moon-spacecraft, or phase, angle of about 160 degrees relative to both moons. Image scale is 23 kilometers (15 miles) per pixel on Enceladus and 32 kilometers (20 miles) on Titan.

Iapetus, the Two-Faced Moon
http://photojournal.jpl.nasa.gov/jpegMod/PIA08234_modest.jpg
World of Contrast
August 2, 2006 Full-Res: PIA08234 (http://photojournal.jpl.nasa.gov/catalog/PIA08234)

This Cassini spacecraft view shows how the bright and dark regions on Iapetus fit together like the seams of a baseball. Some of the material that covers the moon's dark, leading side spills over into regions on the brighter trailing side, creating the feature near upper right referred to by some scientists as "the Moat."

(See Iapetus by Saturn Shine (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1274) for a higher resolution view of this region.)

The large impact basin above center in the dark terrain has a diameter of about 550 kilometers (340 miles).

This view looks toward the Saturn-facing hemisphere of Iapetus (1,468 kilometers, or 912 miles across). North is up.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 25, 2006 at a distance of approximately 1.6 million kilometers (1 million miles) from Iapetus. Image scale is 9 kilometers (6 miles) per pixel.

initialsBB

2006-08-09, 19:03

Excellent thread. Great work and hats off, curiusuburb !

curiousuburb

2006-10-07, 08:16

http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA08732-br402.jpg (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=694)

'Chinese Lantern' Technique Helps Track Clouds at Saturn
October 5, 2006

The image was made with data from Cassini's visual and infrared mapping spectrometer, which can image the planet at 352 different wavelengths.

A new image of Saturn demonstrates a technique that creates a 'Chinese lantern' effect, showing Saturn's deep clouds silhouetted against the planet's warm, glowing interior. Seen this way, Saturn's interior shows surprising activity underneath the overlying haze, with a great variety of cloud shapes and sizes.

Because upper-level hazes and clouds obscure the view of these deep clouds in visible light, imaging clouds in the depths of Saturn is not practical using visible-light cameras. Several recent images obtained by Cassini's visual and infrared mapping spectrometer were combined in a way that highlights the deep clouds in silhouette against the background radiation of heat generated by Saturn's interior. This literally lights the planet from the inside, like a lantern.

Clouds and hazes in Saturn's northern hemisphere are noticeably thinner than those in its southern hemisphere. This is thought to be a seasonal effect; this idea will be tested as Saturn's northern hemisphere enters springtime in the next few years.

Bright red colors indicate areas relatively free of deep-level clouds and particles, while darker red colors are cloudy regions. Images like these show Saturn's deep clouds under both daytime and nighttime conditions.

New Ring discovered... and Earth makes a cameo appearance for Cassini

click images for links
Scientists Discover New Ring and Other Features at Saturn
September 19, 2006
(Source: Jet Propulsion Laboratory / Space Science Institute)

Saturn sports a new ring in an image taken by NASA's Cassini spacecraft on Sunday, Sept. 17, during a one-of-a-kind observation.

Other spectacular sights captured by Cassini's cameras include wispy fingers of icy material stretching out tens of thousands of kilometers from the active moon, Enceladus, and a cameo color appearance by planet Earth.

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA08322-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2277)
The new ring is a tenuous feature, and coincides with the orbits of Saturn's moons Janus and Epimetheus

The images were obtained during the longest solar occultation of Cassini's four-year mission. During a solar occultation, the sun passes directly behind Saturn, and Cassini lies in the shadow of Saturn while the rings are brilliantly backlit. Usually, an occultation lasts only about an hour, but this time it was a 12-hour marathon.

Sunday's occultation allowed Cassini to map the presence of microscopic particles that are not normally visible across the ring system. As a result, Cassini saw the entire inner Saturnian system in a new light.

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA08321-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2276)
Wispy fingers of bright, icy material reach tens of thousands of kilometers outward from Saturn's moon Enceladus into the E ring

The new ring is a tenuous feature, visible outside the brighter main rings of Saturn and inside the G and E rings, and coincides with the orbits of Saturn's moons Janus and Epimetheus. Scientists expected that meteoroid impacts on Janus and Epimetheus might kick particles off the moons' surfaces and inject them into Saturn orbit, but they were surprised that a well-defined ring structure exists at this location.

Saturn's extensive, diffuse E ring, the outermost ring, had previously been imaged one small section at a time. The 12-hour marathon enabled scientists to see the entire structure in one view. The moon Enceladus is seen sweeping through the E ring, extending wispy, fingerlike projections into the ring. These very likely consist of tiny ice particles being ejected from Enceladus' south polar geysers, and entering the E-ring.

"Both the new ring and the unexpected structures in the E ring should provide us with important insights into how moons can both release small particles and sculpt their local environments," said Matt Hedman, a research associate working with team member Joseph Burns, an expert in diffuse rings, at Cornell University in Ithaca, N.Y.

http://saturn.jpl.nasa.gov/multimedia/images/rings/images/PIA08324-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2279)
Earth from nearly 1.5 billion kilometers (930 million miles) away

In the latest observations, scientists once again see the bright ghost-like spokes -- transient, dusty, radial structures -- streaking across the middle of Saturn's main rings.

Capping off the new batch of observations, Cassini cast its powerful eyes in our direction and captured Earth, a pale blue orb, and a faint suggestion of our moon. Not since NASA's Voyager 1 spacecraft saw Earth as a pale blue dot from beyond the orbit of Neptune has Earth been imaged in color from the outer solar system.

"Nothing has greater power to alter our perspective of ourselves and our place in the cosmos than these images of Earth we collect from faraway places like Saturn," said Carolyn Porco, Cassini imaging team leader at the Space Science Institute, Boulder, Colo. Porco was one of the Voyager imaging scientists involved in taking the Voyager 'Pale Blue Dot' image. "In the end, the ever-widening view of our own little planet against the immensity of space is perhaps the greatest legacy of all our interplanetary travels."

http://saturn.jpl.nasa.gov/multimedia/images/non-press/images/PIA08323-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2278)
Earth is captured here in a natural color portrait made possible by the passing of Saturn directly in front of the sun from Cassini's point of view

In the coming weeks, several science teams will analyze data collected by Cassini's other instruments during this rare occultation event. The data will help scientists better understand the relationship between the rings and moons, and will give mission planners a clearer picture of ring hazards to avoid during future ring crossings.

Images of the new ring, the E-ring, Enceladus and Earth are available at: http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org .

Moogs

2006-11-10, 16:19

Booya-kasha!

http://news.bbc.co.uk/2/hi/science/nature/6135450.stm

http://news.bbc.co.uk/nol/shared/spl/hi/pop_ups/06/sci_nat_enl_1163157410/img/1.jpg

Moogs

2007-03-07, 19:32

Because this thread rules, that's why....

julesstoop

2007-03-07, 19:52

Thanks for reminding me :)

thegelding

2007-03-27, 15:57

ok, saturn is frankly freaking me out lately...

first the eye, now we have either the galaxies largest gods-eye or a big red stop sign showing up on the opposite pole

http://www.nasa.gov/mission_pages/cassini/media/cassini-20070327.html

g

http://www.nasa.gov/images/content/172400main_pia09187-200.gif

curiousuburb

2007-03-27, 16:26

Holy HexaHurricanes, Batman !

Beaten to the update. Been too busy, but spotted this myself today. :D

Schnauzer

2007-03-27, 21:09

weirdddd :/

drewprops

2007-03-27, 21:20

Not to throw a damper on the Alien Olympics, but what are the chances this is a phenomenon associated with Cassini's imaging system?

The Saturn north pole hexagon has not been visible to Cassini's visual cameras, because it's winter in that area, so the hexagon is under the cover of the long polar night, which lasts about 15 years. The infrared mapping spectrometer can image Saturn in both daytime and nighttime conditions and see deep inside. It imaged the feature with thermal wavelengths near 5 microns (seven times the wavelength visible to the human eye) during a 12-day period beginning on Oct. 30, 2006. As winter wanes over the next two years, the feature may become visible to the visual cameras.

Kickaha

2007-03-27, 21:42

Naw. It's a REALLY HUGE example of a steadystate polygonal vortex.

http://www.physorg.com/news66924222.html

Moogs

2007-03-27, 22:18

I didn't think vortices had sides. :lol:

Kickaha

2007-03-27, 22:35

Read the article. That's the neat part. ;)

Stable vortices that aren't round, but polygonal.

billybobsky

2007-03-27, 22:49

Naw. It's a REALLY HUGE example of a steadystate polygonal vortex.

http://www.physorg.com/news66924222.html

Probably due to a smooth solid like core rotating much much faster than the clouds above...

drewprops

2007-03-27, 22:49

HOLY MOLY!!!!
That hexagon is bigger than three Earths!!!
:eek: :eek: :eek:

Kickaha

2007-03-27, 22:51

Probably due to a smooth solid like core rotating much much faster than the clouds above...

Yeah, I love that the running theory is that it is tidal-locked with the core at a 10+hr period, when according to the polygonal vortex experiment, that core should be frickin' flying.

curiousuburb

2007-03-28, 06:33

But this story on Enceladus outgassing getting ionized and apparently borking the rotation of the magnetic field (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=733) implies that we still don't know the actual rotation period of Saturn itself.

Enceladus Geysers Mask the Length of Saturn's Day
March 22, 2007
(Source: Jet Propulsion Laboratory)

In a David and Goliath story of Saturnian proportions, the little moon Enceladus is weighing down giant Saturn's magnetic field so much that the field is rotating slower than the planet. This phenomenon makes it nearly impossible to measure the length of the Saturn day using techniques that work at the other giant planets.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG002545-br500.jpg <--- Not to scale, obviously

Geysers on Saturn's little moon Enceladus are throwing off Saturn's internal clock, making it hard to measure the length of the Saturn day.
Hear Sounds from Saturn (http://www.jpl.nasa.gov/multimedia/audioclips/cassini-20070322/)

"No one could have predicted that the little moon Enceladus would have such an influence on the radio technique that has been used for years to determine the length of the Saturn day," said Dr. Don Gurnett of the University of Iowa, Iowa City. Gurnett is the principal investigator on the radio and plasma wave science experiment onboard NASA's Cassini spacecraft. The radio technique measures the rotation of the planet by taking its radio pulse rate -- the rhythm of natural radio signals from the planet.

A new study of Cassini data reported this week in the online version of the journal Science determined that Saturn's magnetic field lines, invisible lines originating from the interior of a magnetized planet, are being forced to slip relative to the rotation of the planet by the weight of electrically charged particles originating from geysers spewing water vapor and ice from Enceladus. These results are based on joint observations by two Cassini instruments -- the radio and plasma wave instrument and the magnetometer.

The neutral gas particles ejected from the geysers on Enceladus form a donut-like torus around Saturn. As these particles become electrically charged, they are captured by Saturn's magnetic field, forming a disk of ionized gas, or plasma, which surrounds the planet near the equator. The particles weigh down the magnetic field so much that the rate of rotation of the plasma disk slows down slightly. This slippage causes the radio period, controlled by the plasma disk rotation, to be longer than the planet's actual rotation period.

Scientists conclude the period Cassini has been measuring from radio emission is not the length of the Saturn day, but rather the rotation period of the plasma disk. At present, because of Saturn's cloud motion, no technique is known that can accurately measure the planet's actual internal rotation.

Finding out the length of Saturn's day has been a challenge because the gaseous planet has no surface or fixed point to clock its rotation rate. Initially, the approach was to use periodic regular radio signals, as has been done for Jupiter, Uranus and Neptune.

However, Saturn's radio period has turned out to be troubling in two ways. It seems to be a pulsed signal rather than a rotating, lighthouse-like beam. Secondly, the period seems to be slowly changing over months to years. The day measured by Cassini is some six minutes longer than the day recorded by NASA's Voyager spacecraft in the early 1980s, a change of nearly 1 percent.

"We have linked the pulsing radio signal to a rotating magnetic signal. Once each rotation of Saturn's magnetic field, an asymmetry in the field triggers a burst of radio waves," said Dr. David Southwood, co-author, Imperial College London, and director of science at the European Space Agency. "We have then linked both signals to material that has come from Enceladus."

Based on the new observations, scientists now think there are two possible reasons for the change in radio period. The first theory is that the geysers on Enceladus could be more active now than in Voyagers' time. The second is that there may be seasonal variations as Saturn orbits the sun once every 29 years.

"One would predict that when the geysers are very active, the particles load down the magnetic field and increase the slippage of the plasma disk, thereby increasing the radio emission period even more. If the geysers are less active, there would be less of a load on the magnetic field, and therefore less slippage of the plasma disk, and a shorter period," said Gurnett.

"The direct link between radio, magnetic field and deep planetary rotation has been taken for granted up to now. Saturn is showing we need to think further," said Michele Dougherty, principal investigator on Cassini's magnetometer instrument, Imperial College London.

The Saturn radio emissions detected by Cassini have been converted into an audio file available at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Moogs

2007-03-28, 12:01

That is bad-ass, I must say...

Also I caught part of a show on M-theory last night where they've apparently decided it's possible that the big-bang was nothing more than the "membranes" of two parallel universes touching at a specific point, as a result of "ripples" or waves. And that therefore time does not have to halt at the big bang but can keep on tracking backwards, and that also there are possibly countless such universal planes, floating around out there...

...because you know this cosmological stuff isn't mind-boggling enough already! We need to be more baffled! :)

Moogs

2007-04-25, 00:12

Thought I would borrow your thread for a bit... seems we'd better get cracking on the NGT and near-light-speed propulsion. There may now be a destination (http://news.bbc.co.uk/2/hi/science/nature/6589157.stm) about 20 light years away, in case we need to start a human colony outside earth. Maybe in 60 or 70 years the technology will exist to contemplate going there. Assuming there are no locals and assuming if there are, that we're welcome. I know I wouldn't invite us over for dinner. :D

curiousuburb

2007-05-06, 10:33

Two new stunners from the spacecraft. Next Titan Flyby under 9 days.

http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA08933-br500.jpg
An Icy Composition
May 4, 2007 Full-Res: PIA08933 (http://photojournal.jpl.nasa.gov/catalog/PIA08933)

The Cassini spacecraft looks across Saturn's cloud-dotted north and shadowed pole, and out across the lanes of ice that compose its rings.
Prometheus (102 kilometers, or 63 miles across) is visible between the A and F rings near the center of the image.

This view looks toward the unilluminated side of the rings from about 42 degrees above the ringplane. The planet's shadow stretches toward the lower right corner.

The image was taken in visible light with the Cassini spacecraft wide-angle camera on April 1, 2007 at a distance of approximately 2 million kilometers (1.2 million miles) from Saturn. Image scale is 119 kilometers (74 miles) per pixel.

http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA08932-br500.jpg
My Blue Heaven
May 3, 2007 Full-Res: PIA08932 (http://photojournal.jpl.nasa.gov/catalog/PIA08932)

In Saturn's bluish north, day ends for the dreamy white clouds that stretch here into twilight.
This natural color scene shows middle latitudes in Saturn's north at excellent resolution, and with little detectable blur due to spacecraft motion.

North on Saturn is up and rotated 22 degrees to the right.

Images taken using red, green and blue spectral filters were combined to create this color view. The image was taken with the Cassini spacecraft narrow-angle camera on April 1, 2007 at a distance of approximately 2 million kilometers (1.2 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 86 degrees. Image scale is about 12 kilometers (7 miles) per pixel.

Moogs

2007-05-06, 13:21

Man... that is one mind-bogglingly large planet. Hard to believe there's nothing under there but gas and a metallic core.

curiousuburb

2007-06-05, 11:06

Huygens discovers evidence of hidden ocean on Titan

Titan’s mysterious radio wave (http://www.esa.int/SPECIALS/Cassini-Huygens/SEM17F9RR1F_0.html)
http://www.esa.int/images/PIA09034_L,0.jpg (http://www.esa.int/SPECIALS/Cassini-Huygens/SEM17F9RR1F_1.html)
Titan's full disk
1 June 2007

Huygens scored a first in 2005 by measuring the electrical conductivity of Titan’s atmosphere. The results hint at a new way to investigate the subsurface layers of Titan and could provide insight into whether or not Titan has a subsurface ocean.

The Permittivity, Waves and Altimetry (PWA) sensor on the Huygens Atmosphere Structure Instrument (HASI) detected an extremely low frequency (ELF) radio wave during the descent. It was oscillating very slowly for a radio wave, just 36 times a second, and increased slightly in frequency as the probe reached lower altitudes.

If the PWA team confirms that the signal is a natural phenomenon and not an artefact of the way the instrument worked, they will have discovered a powerful new way to probe not just the atmosphere of Titan but its subsurface as well.

The only other world on which ELF waves were detected before was Earth. They are reflected by both the surface of the Earth and its ionosphere, the rarefied region of the atmosphere where most particles are electrically charged. This turns the atmosphere into a giant ‘sound box’ where certain frequencies of ELF waves resonate and are reinforced, whilst other die away.

On Titan, however, the surface is a poor reflector because of its low conductivity and so these waves penetrate the interior. “The wave could have been reflected by the liquid-ice boundary of a subsurface ocean of water and ammonia predicted by theoretical models,” says Fernando Simões, CETP/IPSL-CNRS, France, and a member of the PWA team.

http://www.esa.int/images/Simoes_Figure1_M.jpg (http://www.esa.int/SPECIALS/Cassini-Huygens/SEM17F9RR1F_1.html#subhead1)
Sketch of radio wave detected during Huygens' descent

If Simões is right, successful modelling of how ELF waves resonate on Titan could lend support to the ocean’s existence and tell scientists about the depth at which it sits. Understanding the resonance however, is difficult.

Above about 100 kilometres altitude on Earth, the ionosphere provides the upper reflecting layer of the resonating cavity. At Titan, PWA revealed that things are more complicated. Apart from the ionosphere, at a much higher altitude of about 1200 kilometres, Huygens found a layer of ionized particles consisting of electrons, at 63 kilometres. “This does not match any previous prediction for Titan,” says Simões. To some extent, it splits Titan’s atmosphere into two resonating chambers.

With so much at stake, the PWA team are checking to make sure the detection is real and not an artefact generated by the spacecraft. They have already ruled out electrical interference from the instrument itself.

Two small arms, one on either side of Huygens, create an antenna and the team’s next goal is to investigate whether the arms could have oscillated during the descent. Simões and colleagues are building a special chamber to hold a replica of the instrument at the low temperature of Titan’s atmosphere, between 100-200 degrees Kelvin (about -173 to -73 °C), in order to check whether the antenna resonates at 36 hertz. If it does, it probably means that the signal is an artefact. If it does not, confidence in the signal’s reality will increase and the investigation of the atmosphere and subsurface can begin.

http://www.esa.int/images/Hamelin_PWA_MI_PSS_Fig1_H_medium,0.jpg (http://www.esa.int/SPECIALS/Cassini-Huygens/SEM17F9RR1F_1.html#subhead2)
Graph of electron density in Titan's atmosphere

But perhaps the biggest mystery is what generated the ELF wave in the first place. On Earth, they are initiated by lightning strikes that make electrons in the atmosphere oscillate, releasing the ELF waves.

The PWA was designed to search for ELF waves on Titan while a microphone on Huygens kept an ear out for thunder – a sure sign of lightning. Cassini has also been watching for lightning using its cameras.

However, Huygens suggests that there is no lightning, or very little. “If there is lightning on Titan, it is significantly less than the amount of lightning that Earth experiences,” says Simões. So what generated Titan’s ELF? No one is quite sure yet. “It might be generated by an interaction with Saturn’s magnetosphere or related to Titan’s intrinsic fields,” suggests Simões. “Titan is proving to be an intriguing environment.”

One thing is certain: there is plenty to investigate. “The measurement of atmospheric electricity is something really new and exciting,” says Jean-Pierre Lebreton, ESA Huygens Project Scientist. “We could send similar instruments to study atmospheric electricity on other celestial bodies, in particular Venus, Mars, and the giant planets,” adds Simões.

The PWA team expect to release more definitive results when their investigation is complete.

Notes for editors

This article is based on two papers that will appear in a special issue of the Planetary and Space Science magazine dedicated to Huygens results: ‘Electron conductivity and density profiles derived from the Mutual Impendence Probe measurements performed during the descent of Huygens through the atmosphere of Titan’, by M. Hamelin et al., and ‘A new numerical model for the simulation of ELF wave propagation and the computation of eigenmodes in the atmosphere of Titan: did Huygens observe any Schumann Resonance?’, by F. Simões et al.

Mugge

2007-06-05, 11:19

Cool. Now how do we get a submarine up there?

:cool:

curiousuburb

2007-06-05, 11:38

Call the Moravecs (http://ilium.pbwiki.com/Moravec)... oh wait... wrong gas giant (http://en.wikipedia.org/wiki/Ilium_%28novel%29).

(Mahnmut in Illium is a Europan Submariner.)

Mugge

2007-06-05, 11:47

Call the Moravecs (http://ilium.pbwiki.com/Moravec)... oh wait... wrong gas giant (http://en.wikipedia.org/wiki/Ilium_%28novel%29).

(Mahnmut in Illium is a Europan Submariner.)

You confuse me with sci-fi, as if this space magnetism shit wasn't complicated enough to begin with.

:)

Moogs

2007-06-05, 12:52

This stuff is a trip... how amazing that we're doing this kind of science. Gives me hope for mankind, if we can keep from asploding each other, dying from plagues, etc.

curiousuburb

2007-07-23, 11:24

Iapetus Bulge explained

http://a52.g.akamaitech.net/f/52/827/1d/www.space.com/images/050111_iod_iapetus_02.jpg (http://www.space.com/scienceastronomy/070723_iapetus_shape.html)

Walnut-Shaped Moon's Mystery Solved
By Dave Mosher
Staff Writer
posted: 23 July 2007
06:46 am ET

There's a strange moon whizzing around Saturn that's shaped, oddly, like a walnut.

Now astronomers find that Iapetus got its nutty shape from a super-fast spin that was frozen into place early in the solar system's formation.

When the Cassini spacecraft snapped close-ups of Saturn's moons in 2005, it revealed a bulging waistline of rock along the equator of the now slowly spinning Iapetus. Astronomers think this characteristic shape persists because Iapetus was cryogenically frozen in time about 3 billion years ago, during the moon's "teen" years.

"Iapetus spun fast, froze young and left behind a body with lasting curves," said Julie Castillo, a Cassini scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

Unlike any other moon in the solar system, Iapetus (eye-APP-eh-tuss) has retained its immature figure. Running exactly along its midsection, a chain of mountains 808 miles (1,300 kilometers) long and 12 miles (19 kilometers) high adds to the moon's walnut-like appearance.

"You would expect a very fast-spinning moon to have this bulge but not a slow-spinning moon, because the bulge would have been much flatter," said Dennis Matson, another Cassini project scientist at JPL. However, Mason said, "we've modeled how Iapetus formed its big, spin-generated bulge and why its rotation slowed down to its present, nearly 80-day period."

Iapetus originally spun once every five to 16 hours, which was fast enough to buckle its surface at the equator, according to the new model detailed in an upcoming online edition of the journal Icarus.

Scientists think radioactive elements heated the moon's interior to permit the crust to stretch and buckle, yet quickly froze the moon into shape as fuel ran out.

"Iapetus' development literally stopped in its tracks," Castillo said of the 4.564 billion-year-old hunk of rock. In order to slow the young moon down its present once-per-80-days rotational speed, Castillo explained, "its interior had to be much warmer, close to the melting point for water ice."

The finding should help astronomers better understand how the planets and their moon systems formed in the early solar system.

"This is the first direct evidence of the early spin history for a satellite in the outer solar system," Matson said. "It ... broadens our knowledge of the early history of outer planet satellites."

Saturn's Old Moon Iapetus Retains its Youthful Figure
July 17, 2007
(Source: Jet Propulsion Laboratory) Press Release (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=761)

Saturn's distinctive moon Iapetus (eye-APP-eh-tuss) is cryogenically frozen in the equivalent of its teenage years. The moon has retained the youthful figure and bulging waistline it sported more than three billion years ago, scientists report.

Unlike any other moon in the solar system, Iapetus is the same shape today as it was when it was just a few hundred million years old.
"Iapetus spun fast, froze young, and left behind a body with lasting curves," said Julie Castillo, Cassini scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA06166-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1270)
Unlike any other moon in the solar system, Iapetus is the same shape today as it was when it was just a few hundred million years old; a well-preserved relic from the time when the solar system was young. These results appear in the online version of the journal Icarus.

Cassini flew by Iapetus in early 2005 and discovered the moon had a walnut shape, bulging at its midsection. On top of that it has a chain of mountains located exactly along its equator.

Scientists now think the moon's bulging midriff and slow spin rate point to heating from long-extinct radioactive elements present when the solar system was born.

"We've modeled how Iapetus formed its big, spin-generated bulge and why its rotation slowed down to its present nearly 80-day period. As an unexpected bonus, Iapetus also told us how old it was," said Dennis Matson, Cassini project scientist at JPL. "You would expect a very fast-spinning moon to have this bulge, but not a slow-spinning moon, because the bulge would have been much flatter."

Scientists calculate Iapetus originally rotated much faster -- at least five hours, but less than 16 hours per revolution. The fast spin gave the moon an oblate shape that increased the surface area (in the same way the surface area of a round balloon stretches when the balloon is pressed into an oblate shape). By the time the rotation slowed down to a period of 16 hours, the outer shell of the moon had frozen. Furthermore, the surface area of the cold moon was now smaller. The excess surface material was too rigid to go back smoothly into the moon. Instead, it piled up in a chain of mountains at the equator.

"Iapetus' development literally stopped in its tracks," said Castillo. "In order for tidal forces to slow Iapetus to its current spin rate, its interior had to be much warmer, close to the melting point for water ice." The challenge in developing a model of how Iapetus came to be "frozen in time" has been in deducing how it ever became warm enough to form a bulge in the first place, and figuring out what caused the heat source to turn off, leaving Iapetus to freeze.

The heat source had to have a limited life span, to allow the moon's crust to rapidly become cold and retain its immature shape. After looking at several models, scientists concluded that the heat came from its rocks, which contain short-lived radioactive isotopes aluminum-26 and iron-60 (which decay very rapidly on a geologic timescale). Since these elements decay at a known rate, this allowed scientists to "carbon date" Iapetus by using aluminum-26 instead of carbon. Scientists calculate the age of Iapetus to be roughly 4.564 billion years old.

Evidence for these same isotopes (aluminum-26 and iron-60) has been found in meteorites formed in the inner solar system. Therefore, there is a possibility of comparing the early chronology of the outer solar system with other objects in the inner solar system, such as Earth, Earth's moon and asteroids.

"This is the first direct evidence of the early spin history for a satellite in the outer solar system. It teaches us more about how the speed of a body's rotation influenced its evolution, and broadens our knowledge of the early history of outer planet satellites," said Matson.

Cassini's next close encounter with Iapetus will occur on Sept. 10, 2007, at 1,000 kilometers (620 miles) from the surface.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C.

More information on the Cassini mission is available at: http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .

Saturnian Moon count reaches 60

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG002675-br500.jpg
Saturn Turns 60
Jul. 19, 2007
(Source: JPL)

Scientists have recently discovered that the planet Saturn is turning 60 -- not years, but moons.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG002675-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2675)
Initial calculations show the moon to have a width of approximately 2 kilometers (1.2 miles), with an orbit that lies between those of the moons Methone and Pallene.

View QT Movie (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=158'))
The 60th moon of Saturn reveals itself in a sequence of images. The discovery suggests that the new moon, along with its neighbors Methone and Pallene (discovered by the Cassini imaging team in 2004), may form part of a larger group of moons in this region. The movie spans six hours.

Initial calculations show the moon to have a width of approximately 2 kilometers (1.2 miles), with an orbit that lies between those of the moons Methone and Pallene. The moon's orbit is in resonance with another moon, Mimas, also seen in this sequence as a very bright, moving object. The new moon's location is indicated by a red box.

The (narrow) ring visible in the images is the G ring, and the G ring arc passes through the field of view during the course of the movie. Calypso, a Trojan moon of Tethys, is also visible in the sequence. Trojan moons are found near gravitationally stable points ahead or behind a larger moon.

This view looks toward the non-illuminated side of the rings from about 3 degrees above the ringplane.

The series of images was taken in visible light with the Cassini spacecraft wide-angle camera on May 30, 2007, at a distance of approximately 1.76 million kilometers (1.09 million miles) from Saturn. Image scale is about 105 kilometers (65 miles) per pixel. The ghostly shape that stretches across the scene results from scattered light within the camera optics.
"We detected the 60th moon orbiting Saturn using the Cassini spacecraft's powerful wide-angle camera," said Carl Murray, a Cassini imaging team scientist from Queen Mary, University of London. "I was looking at images of the region near the Saturnian moons Methone and Pallene and something caught my eye."

The newly discovered moon first appeared as a very faint dot in a series of images Cassini took of the Saturnian ring system on May 30 of this year. After the initial detection, Murray and fellow Cassini imaging scientists played interplanetary detective, searching for clues of the new moon in the voluminous library of Cassini images to date.

The Cassini imaging team's legwork paid off. They were able to locate numerous additional detections, spanning from June 2004 to June 2007. "With these new data sets we were able to establish a good orbit for the new moon," said Murray. "Knowing where the moons are at all times is important to the Cassini mission for several reasons."

One of the most important reasons for Cassini to chronicle these previously unknown space rocks is so the spacecraft itself does not run into them. Another reason is each discovery helps provide a better understanding about how Saturn's ring system and all its billions upon billions of parts work and interact together. Finally, a discovery of a moon is important because with this new knowledge, the Cassini mission planners and science team can plan to perform science experiments during future observations if and when the opportunity presents itself.

What of this new, 60th discovered moon of Saturn? Cassini scientists believe "Frank" (the working name for the moon until another, perhaps, more appropriate one is found) is about 2 kilometers (1.2 miles) wide and, like so many of its neighbors, is made mostly of ice and rock. The moon's location in the Saturnian sky is between the orbits of Methone and Pallene. It is the fifth moon discovered by the Cassini imaging team.

"When the Cassini mission launched back in 1997, we knew of only 18 moons orbiting Saturn," said Murray. "Now, between Earth-based telescopes and Cassini we have more than tripled that number -- and each and every new discovery adds another piece to the puzzle and becomes another new world to explore."

Murray and his colleagues may get the chance to explore Saturn's 60th moon. The Cassini spacecraft's trajectory will put it within 11,700 kilometers (7,300 miles) in December of 2009.

Cheers to the new moon named... Frank. :\ ;)

curiousuburb

2007-09-27, 17:50

Cassini's only close (1600 km) flyby of the curious moon Iapetus (discovered by the original Giovanni Cassini in 1671) is done.

Despite a cosmic ray hit that put the spacecraft into safe mode and delayed downlink of the data, there are some impressive new images of the 'yin-yang moon' with the walnut ridge.

http://saturn.jpl.nasa.gov/multimedia/images/non-press/images/IMG002731-th100.jpg (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=774)
Scientists on the Cassini mission to Saturn are poring through hundreds of images returned from the Sept. 10 flyby of Saturn's two-toned moon Iapetus. Pictures returned late Tuesday and early Wednesday show the moon's yin and yang -- a white hemisphere resembling snow, and the other as black as tar.

Cassini's Closest Visit of Iapetus

On Sept. 10, the Cassini spacecraft performs its closest flyby during the entire mission of the odd moon Iapetus, passing by about 1,640 kilometers (1,000 miles).

Iapetus is a world of sharp contrasts. The leading hemisphere is as dark as a freshly-tarred street, and the white, trailing hemisphere resembles freshly-fallen snow. Scientists want to know more about the composition of the dark material that coats Iapetus. They also want to learn more about Iapetus' distinctive walnut shape and the chain of mountains along its equator.

Saturn's Moon Iapetus is the Yin-and-Yang of the Solar System (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=774)
September 12, 2007
(Source: NASA/JPL/Space Science Institute)

http://saturn.jpl.nasa.gov/multimedia/images/newsevents/images/PIA08372-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2732)This close-up view shows mountainous terrain that reaches about 10 kilometers (6 miles) high along the unique equatorial ridge of Iapetus.

PASADENA, Calif. -- Scientists on the Cassini mission to Saturn are poring through hundreds of images returned from the Sept. 10 flyby of Saturn's two-toned moon Iapetus. Pictures returned late Tuesday and early Wednesday show the moon's yin and yang -- a white hemisphere resembling snow, and the other as black as tar.

Images show a surface that is heavily cratered, along with the mountain ridge that runs along the moon's equator. Many of the close-up observations focused on studying the strange 20-kilometer high (12 mile) mountain ridge that gives the moon a walnut-shaped appearance.

"The images are really stunning," said Tilmann Denk, Cassini imaging scientist at the Free University in Berlin, Germany, who was responsible for the imaging observation planning. "Every new picture contained its own charm. I was most pleased about the images showing huge mountains rising over the horizon. I knew about this scenic viewing opportunity for more than seven years, and now the real images suddenly materialized."

This flyby was nearly 100 times closer to Iapetus than Cassini's 2004 flyby, bringing the spacecraft to about 1,640 kilometers (1,000 miles) from the surface. The moon's irregular walnut shape, the mountain ridge that lies almost directly on the equator and Iapetus' brightness contrast are among the key mysteries scientists are trying to solve.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08374-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2733)This image shows terrain in the transition region between the moon's dark leading hemisphere and its bright trailing hemisphere.
"There's never a dull moment on this mission," said Bob Mitchell, Cassini program manager, NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We are very excited about the stunning images being returned. There's plenty here to keep many scientists busy for many years."

"Our flight over the surface of Iapetus was like a non-stop free fall, down the rabbit hole, directly into Wonderland! Very few places in our solar system are more bizarre than the patchwork of pitch dark and snowy bright we've seen on this moon," said Carolyn Porco, Cassini imaging team leader at the Space Science Institute, Boulder, Colo.

The return of images and other data was delayed early Tuesday due to a galactic cosmic ray hit which put the spacecraft into a precautionary state called safe mode. This occurred after the spacecraft had placed all of the flyby data on its data recorders and during the first few minutes after it began sending the data home. The data flow resumed later that day and concluded on Wednesday. The spacecraft is operating normally and its instruments are expected to return to normal operations in a few days.

"Iapetus provides us a window back in time, to the formation of the planets over four billion years ago. Since then its icy crust has been cold and stiff, preserving this ancient surface for our study," said Torrence Johnson, Cassini imaging team member at JPL.

Cassini's multiple observations of Iapetus will help to characterize the chemical composition of the surface; look for evidence of a faint atmosphere or erupting gas plumes; and map the nighttime temperature of the surface. These and other results will be analyzed in the weeks to come.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08375-th120.jpgThe 'Voyager' Mountains (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2736) http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08373-th120.jpgCoated Craters (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2735) http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08374-th120.jpgInky Stains on a Frozen Moon (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2733)
http://saturn.jpl.nasa.gov/multimedia/images/newsevents/images/PIA08372-th120.jpgThe Himalayas of Iapetus (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2732) http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08371-th120.jpgEyes on Iapetus! (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2721) http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA09970-th120.jpgExposing Iapetus' Dark Side (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2720)

More Iapetus flyby images are available at: http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini and http://ciclops.org.

http://saturn.jpl.nasa.gov/multimedia/images/videothumbnails/images/IMG002738-br500.jpg (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=160)
And Arthur C Clarke webcast a message (click pic above for link) for the JPL/Cassini folks to mark the flyby of the moon he actually chose for the big Monolith in 2001. The clip explains why Kubrick switched to Jupiter in the film when the book used Saturn.

Space science and film trivia connected by a brilliantly prescient author... trifecta! ;)

Moogs

2007-11-06, 23:25

Sorta related

http://news.bbc.co.uk/2/hi/science/nature/7082257.stm

Seems the Cancri system is uber-planetized.

Moogs

2007-12-17, 21:36

More Astro-news.... we're always talking about planets getting pummeled by asteroids and such. How about every planetary system on the edge of an entire galaxy getting wiped out by a SMBH "jet"?

http://news.bbc.co.uk/2/hi/science/nature/7148671.stm

:eek:

curiousuburb

2007-12-18, 07:53

Meanwhile, the boffins are bickering over the composition of the Enceladus jets.

Grains of salt should be taken when reading this story... but might not be detected. ;)

http://news.bbc.co.uk/1/hi/sci/tech/7145530.stm

Sodium issue clouds Enceladus
By Molly Bentley
Science reporter, San Francisco
Dec 16, 2007

http://newsimg.bbc.co.uk/media/images/44170000/jpg/_44170162_jets_nasa_203b.jpg
Next year, Cassini will attempt to fly through the jets

An ocean is not the source of the jets emanating from Saturn's moon Enceladus, a new study concludes.

The research questions the moon's promise as a target in the search for life beyond Earth and has stirred controversy among scientists who dispute its conclusions.

A chemical analysis of Enceladus, led by University of Colorado planetary scientist Nick Schneider, failed to detect sodium, an element scientists say should be in a body of water that has had billions of years of contact with rock.

"If you have a long-lived ocean, it's going to have salt in it," said Dr Schneider, at the American Geophysical Union (AGU) meeting in San Francisco this week, "but that ocean, if it exists on Enceladus, isn't leaking out into space."

Spectral analysis with the Keck Telescope found no sodium in the plumes or in the vapour that's in orbit around the moon.

The source of the plumes is "very, very pure water," Dr Schneider concluded, and proposed clean ice, melt water or clathrates - a crystal of water, carbon dioxide and ammonia - as alternative sources.

Heated debate

The fountains on Enceladus tantalise scientists by suggesting an ocean beneath the moon's icy crust. An ancient sea is the best bet for where life might evolve off Earth, scientists say.

At stake is whether Saturn's moon could support alien life and is a worthy target for a US space agency (Nasa) exploratory mission to detect it. Such a mission to Enceladus is one of four currently under review for further development.

If you took salt from a salt-shaker and threw it into the air, the telescope wouldn't see any sodium, even though half the salt is sodium
Torrence Johnson, Cassini Imaging Team

Dr Schneider didn't rule out the possibility of an ocean on Enceladus, only that it is the source of the spraying water.

Critics of the study accept his observations, but disagree with his conclusion; and it has led to some robust exchanges here at the AGU meeting this past week.

"There is tremendous dispute about his interpretation of the results," said Carolyn Porco, the Imaging Team leader on the Cassini spacecraft.

He may not have detected sodium, she said, but it did not follow that the plumes were not connected to an ocean.

The absence of detectable sodium might mean only that; it's not detectible, said Dr Porco. It could be in a solid form that eludes detection by this method, she said.

Salty secrets

Dr Schneider used the Keck Telescope to look for a glow from sodium atoms, the same colour found in sodium streetlights. He failed to detect it in the plume or in the ring of particles that encircle Saturn at Enceladus' orbit.

http://newsimg.bbc.co.uk/media/images/44302000/jpg/_44302584_enceladuscon_nasa_203.jpgENCELADUS ORBITER CONCEPT

To look at biological potential, composition and structure
Instruments to image and sample surface and jets
Lander to provide unique close-up view of surface processes
Probable cost about $3bn; 2018 launch on biggest Delta rocket

Yet sodium is quite abundant in the Solar System, said Torrence Johnson, Cassini Imaging Team member at Nasa's Jet Propulsion Laboratory.

"It's a very surprising result not to find sodium at all," he explained. "So the question is: can you hide the sodium?"

One way to hide sodium is to put it in a salt crystal that becomes the nucleus of a water particle. If a sodium atom were tied up in a solid form, the Keck Telescope would not detect it. It only detects liberated sodium atoms, he said.

"If you took salt from a salt-shaker and threw it into the air, the telescope wouldn't see any sodium, even though half the salt is sodium," added Dr Johnson.

Dr Schneider said that the molecules would release sodium as they made their way into the particles that encircle Saturn.

Near fly-by

Scientists have detected sodium around Jupiter's moons Io and Europa. Volcanoes produce Io's sodium and their heat liberates it. Scientists believe Jupiter's energetic radiation belt kicks the sodium out of minerals that entrap it on Europa.

But Saturn is cooler in temperature and its radiation levels may also be too weak to free sodium.

At any rate, said Dr Johnson, the sodium-free test results do not rule out the existence of an ocean on the moon or an ocean as the source of the plumes.

The Cassini spacecraft is scheduled to fly close to the jets in March of next year. It will analyse the water further, but is not able to test for sodium.

Nonetheless, the discovery of water spewing from cracks - dubbed "tiger stripes" -on Enceladus in 2006, has promoted the moon into an elite club of outer Solar System bodies that are considered high priority for future Nasa missions.

Design competition

The possibility that the plumes tap directly into a lunar ocean is the impetus behind a flagship mission that would explore Enceladus further.

A spacecraft that flew through the spray might be designed to sample the water directly and run tests to detect the presence of alien microbes.

http://news.bbc.co.uk/nol/shared/spl/hi/pop_ups/07/sci_nat_enl_1192103612/img/laun.jpg
The tiger stripes, or sulci, are now the focus of intense study

More details (http://news.bbc.co.uk/1/shared/spl/hi/pop_ups/07/sci_nat_enl_1192103612/html/1.stm)
The mission is much more difficult - and expensive - if the data is not obtainable at altitude and a lander has to be put on the icy surface to reach it.

The Enceladus flagship mission is one of four - along with those to Europa, Titan and Jupiter - competing for funding and currently under review by Nasa.

Dr Johnson says Dr Schneider's study might influence how inclined people are to send a spacecraft to Enceladus and fly through the plumes.

"If Nick is right," he said, "all they'd see is pure water."

Nasa is scheduled to select which flagship missions will advance at the end of December.

The concept that eventually emerges in the process will launch no earlier than 2015 and is likely to include sizeable input from the Europeans.

curiousuburb

2008-02-09, 16:13

http://saturn.jpl.nasa.gov/multimedia/images/non-press/images/IMG002935-br402.jpg
Cassini at Saturn Interactive Explorer (CASSIE)
(http://saturn.jpl.nasa.gov/multimedia/CASSIE/)

Real data... handy web 3D browser plugin. :D :D :D

Welcome to NASA's first 3-d interactive mission experience using a web browser. Using "Cassini at Saturn Interactive Explorer"(CASSIE) you can observe or ride along with the Cassini spacecraft as it explores Saturn and its moons using real mission data.

The first time you click on the button below it will automatically download and install the needed software (a free plug-in to your web-browser) and the real Cassini mission data. The download is about 15 megabytes so it should only take a minute or two. (If you use a Mac you may need to install the software after it downloads and then restart your web-browser.) Once the plug-in is installed and the mission data is loaded you're ready for your trip to the Saturn System.

When CASSIE appears in your web browser, you'll see three clickable windows.

The Cassini at Saturn Interactive Explorer, or CASSIE, visualizes the real Cassini mission data in these three windows.

(WINDOW 1) The "Where is Cassini Now?" expedition shows exactly where the Cassini spacecraft is, and what it is doing each moment over a 24-hour period in real time. Viewers can see the spacecraft move along its course and maneuver according to instructions from mission scientists and navigators.

(WINDOW 2) The "Mission Overview" expedition, shows the spacecraft as it orbits the Saturn system over the last 3.5 years and fast-forward into the future to see where it is going. Users can switch between two camera angles to see Cassini fly by Saturn and its moons.

(WINDOW 3) The "Saturn's Moons" expedition gives an in-depth peek at seven of Saturn's moons, providing useful facts and interactive surface views of each moon.

Teh Coolness!

curiousuburb

2008-03-12, 13:50

Enceladus close pass in 1 hour.

http://saturn.jpl.nasa.gov/multimedia/images/artwork/images/IMG002983-br402.jpg

50km above the surface and through the geysers at under 200km altitude to sample the contents.

Sadly, the imaging array will be turned out to space during the geyser dive so that the particle analyzers can get their best sniff.

http://saturn.jpl.nasa.gov/multimedia/images/videothumbnails/images/IMG002976-br500.jpgClick for video (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=171)
On March 12, NASA's Cassini spacecraft will make its closest flyby yet to Saturn's moon Enceladus. Cassini's goal: To scoop up samples of water-ice particles and gas spewing from Old-Faithful-like geysers.

Cassini Spacecraft to Dive Into Water Plume of Saturn Moon
March 10, 2008
(Source: NASA/JPL)
NASA's Cassini spacecraft will make an unprecedented "in your face" flyby of Saturn's moon Enceladus on Wed., March 12.

The spacecraft, orchestrating its closest approach to date, will skirt along the edges of huge Old-Faithful-like geysers erupting from giant fractures on the south pole of Enceladus. Cassini will sample scientifically valuable water-ice, dust and gas in the plume.

The source of the geysers is of great interest to scientists who think liquid water, perhaps even an ocean, may exist in the area. While flying through the edge of the plumes, Cassini will be approximately 200 kilometers (120 miles) from the surface. At closest approach to Enceladus, Cassini will be only 50 kilometers (30 miles) from the moon.

http://saturn.jpl.nasa.gov/multimedia/images/artwork/images/IMG002985-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2985)This graphic shows the trajectory for the Cassini spacecraft during its close brush with the icy outpost of Enceladus on March 12, 2008. At closet approach Cassini will be 50 kilometers (30 miles) from the surface, while flying through the plume Cassini's altitude will be 200 kilometers (120) miles from the moon.

"This daring flyby requires exquisite technical finesse, but it has the potential to revolutionize our knowledge of the geysers of Enceladus. The Cassini mission team is eager to see the scientific results, and so am I," said Alan Stern, associate administrator of NASA's Science Mission Directorate, Washington.

Scientists and mission personnel studying the anatomy of the plumes have found that flying at these close distances poses little threat to Cassini because, despite the high speed of Cassini, the plume particles are small. The spacecraft routinely crosses regions made up of dust-size particles in its orbit around Saturn.

Cassini's cameras will take a back seat on this flyby as the main focus turns to the spacecraft's particle analyzers that will study the composition of the plumes. The cameras will image Enceladus on the way in and out, between the observations of the particle analyzers.

Images will reveal northern regions of the moon previously not captured by Cassini. The analyzers will "sniff and taste" the plume. Information on the density, size, composition and speed of the gas and the particles will be collected.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA08408-th200.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2977)
This map of the surface of Saturn's moon Enceladus, generated from images taken by NASA's Cassini and Voyager spacecraft, illustrates the imaging coverage planned for Cassini's very close flyby of the geologically active moon on March 12, 2008.
"There are two types of particles coming from Enceladus, one pure water-ice, the other water-ice mixed with other stuff," said Sascha Kempf, deputy principal investigator for Cassini's Cosmic Dust Analyzer at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. "We think the clean water-ice particles are being bounced off the surface and the dirty water-ice particles are coming from inside the moon. This flyby will show us whether this concept is right or wrong."

In 2005, Cassini's multiple instruments discovered that this icy outpost is gushing water vapor geysers out to a distance of three times the radius of Enceladus. The moon is only 500 kilometers (310 miles) in diameter, but despite its petite size, it's one of the most scientifically compelling bodies in our solar system. The icy water particles are roughly one ten-thousandth of an inch, or about the width of a human hair. The particles and gas escape the surface at jet speed at approximately 400 meters per second (800 miles per hour). The eruptions appear to be continuous, refreshing the surface and generating an enormous halo of fine ice dust around Enceladus, which supplies material to one of Saturn's rings, the E-ring.

Several gases, including water vapor, carbon dioxide, methane, perhaps a little ammonia and either carbon monoxide or nitrogen gas make up the gaseous envelope of the plume.

"We want to know if there is a difference in composition of gases coming from the plume versus the material surrounding the moon. This may help answer the question of how the plume formed," said Hunter Waite, principal investigator for Cassini's Ion and Neutral Mass Spectrometer at the Southwest Research Institute, San Antonio.

This is the first of four Cassini flybys of Enceladus this year. In June, Cassini completes its prime mission, a four-year tour of Saturn. Cassini's next flyby of Enceladus is planned for August, well into Cassini's proposed extended mission. Cassini will perform seven Enceladus flybys in its extended mission. If this encounter proves safe, future passes may bring the spacecraft even closer than this one. How close Cassini will be allowed to approach will be determined based on data from this flyby.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL.

For images, videos and a mission blog on the flyby, visit: http://www.nasa.gov/cassini . More information on the Cassini mission is also available at http://saturn.jpl.nasa.gov .

See also the groovy interactive Enceladus virtual tour.http://saturn.jpl.nasa.gov/multimedia/images/artwork/images/IMG002981-th100.jpg (http://saturn.jpl.nasa.gov/multimedia/flash/Enceladus/enceladus.html)
(With new close up images of the Northern hemisphere due after this flyby).

Oh... and apparently, Rhea has Rings (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=820). First moon in the solar system to have them.

curiousuburb

2008-07-20, 10:09

Cassini picks up a mushroom... Extended mission!¡!

And the CASSIE 3D explorer is updated to v2.0
http://saturn.jpl.nasa.gov/multimedia/images/artwork/images/CASSIE-Interactive_th550.jpg (http://saturn.jpl.nasa.gov/multimedia/CASSIE/)

Cassini's Adventure Ends, and Begins Anew (http://saturn.jpl.nasa.gov/news/features/feature20080627.cfm)
The Cassini Mission was an audacious idea from the start.

Get the world's best space scientists and engineers to build the best and hardiest instruments that they can to study Saturn. Put everything on a spacecraft and launch it to the outer solar system.

Loop twice around Venus, once around Earth, then pass Jupiter. When you get to Saturn, veer right and slam on the brakes. Pass through the rings. Look out for those ice particles! Start orbiting Saturn.

Hang out a lot at Titan - it's smoggy but that's where the action is. Drop off the Huygens Probe there and tell us everything it has to say about what it finds.

Check out Enceladus; something strange is going on there. Go by Iapetus. It is definitely weird. There are a bunch of little moons hiding in and around the rings, making waves and kicking up dust. Find them. And fly way up above Saturn a few times. We've never seen it from that view. Be open to the unexpected. Stay for at least four years. Report back on everything that you see, feel, smell and hear. Take lots of pictures!

Astonishingly, Cassini's historic prime mission has successfully concluded. It may have looked easy, but the mission's success is owed to the careful and hard work of the dedicated international team that built and operates the spacecraft. Now, Cassini embarks on the new Equinox mission with a fresh set of scientific objectives.

Since arriving at the ringed planet four years ago, Cassini has revealed wonder after wonder. The growing body of knowledge about Saturn, its rings, moons and magnetic environment is allowing scientists to link together clues to solve mysteries. For every puzzle solved, Cassini seems to raise 10 more new questions - a happy predicament for scientists.

http://saturn.jpl.nasa.gov/multimedia/images/moons/IMG001003-br500.jpg
(http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1003)
Cassini-Huygens Analysis and Results of the Mission (CHARM)
View June 24, 2008 Presentation (PDF, 13MB) (http://saturn.jpl.nasa.gov/multimedia/products/pdfs/20080624_CHARM_4YearAnniversary.pdf)

Some highlights of the prime, four-year Cassini mission:

Geysers shoot water vapor and ice from warm fissures on Enceladus.
The E-ring of Saturn is made of material from Enceladus' plumes.
Material from Enceladus' plumes adds mass to Saturn's magnetosphere and slows the rotation of Saturn's magnetic field.
Comet-like organic chemicals exist in Enceladus' plumes.
Titan appears to be land of lakes, with hundreds of lake features, probably filled with hydrocarbons.
Titan has a hydrological cycle like Earth's but substitutes methane for water in processes that include methane rain, clouds and apparently, lakes.
Braided channels are carved in Titan's surface -- evidence of heavy flooding.
Small moons, including Hyperion, are dazzlingly varied and strange.
Sahara-like sand dunes exist on Titan, and the sand is probably made up of hydrocarbons that fall from the sky.
An internal ocean likely exists on Titan. It causes Titan's crust to slip about "like cheese on pizza sauce."
Evidence exists for a tenuous ring system around the moon Rhea.
An odd mountain ridge runs around Iapetus' equator.
Detailed studies of Iapetus, frozen in time, shed new light on the early formation of other bodies in the solar system.
The Huygens Probe returned the first close-up views of Titan's haze-covered terrain.
Landing onto damp, icy gravel or sand at edge of a dried-up methane lake, the Huygens Probe provided new insight into the makeup of Titan.
Titan is losing its atmosphere due to bombardment by Saturn's magnetosphere.
Extremely heavy organic compounds, up to 10,000 times heavier than hydrogen - were found high in Titan's atmosphere. These become aerosols and eventually rain down onto Titan's cold surface - they may be the "tholins" predicted by Carl Sagan that comprise a prebiotic chemical soup.
Auroras at Saturn's north and south poles are unlike those found on Earth and Jupiter.
Hot hurricane-like storms churn at both of Saturn's poles.
The temperature structure of Saturn's and Titan's atmospheres were completely mapped, revealing their circulation and dynamics.
The rings have their own atmosphere.
Evidence was found that the rings may be a permanent rather than transitory feature of Saturn

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG002631-th100.jpgEnceladus geysers (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2631) http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA09211-th100.jpgTitan, Land of Lakes. (http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA09211-th100.jpg) http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07761-th100.jpgSpongy Hyperion. (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2614) http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA07232-th100.jpgTitan's landscape, from Huygens (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1310) http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/PIA08332-th100.jpgLong-lived storm at Saturn's south pole. (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2354)

Extended mission should include a ring eclipse in 2009 and fresh approach to a few moons for follow up.

curiousuburb

2008-11-14, 08:55

Cassini has captured Prometheus colliding with the F ring, which creates a "streamer;" material being pulled from the ring by the moon's gravity, leaving behind a dark channel.

Streamer Channel
http://www.universetoday.com/wp-content/uploads/2008/11/prometheus-ring1.jpg (http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=3309)

The Cassini spacecraft focuses on a streamer-channel feature in Saturn's F ring.

These features are created by the moon Prometheus as it closely approaches the ring once per orbit (see Soft Collision).

This view looks toward the unilluminated side of the rings from about 36 degrees above the ringplane.The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 30, 2008. The view was acquired at a distance of approximately 970,000 kilometers (602,000 miles) from Saturn and at a Sun-ring-spacecraft, or phase, angle of 45 degrees. Image scale is 5 kilometers (3 miles) per pixel.

Even better, you can watch it happen...

Soft Collision (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=163)

http://saturn.jpl.nasa.gov/multimedia/images/videothumbnails/images/IMG002800-br500.jpg
MPG (http://saturn.jpl.nasa.gov/multimedia/videos/movies/PIA08397_full_movie.mpg) of the event. QT version (http://saturn.jpl.nasa.gov/multimedia/videos/movies/PIA08397_full_movie.mov)

The moon Prometheus slowly collides with the diffuse inner edge of Saturn's F ring in this movie sequence of Cassini images. The oblong moon pulls a streamer of material from the ring and leaves behind a dark channel.
Once during its 14.7-hour orbit of Saturn, Prometheus (102 kilometers, or 63 miles across) reaches the point in its elliptical path, called apoapse, where it is farthest away from Saturn and closest to the F ring. At this point, Prometheus' gravity is just strong enough to draw a "streamer" of material out of the core region of the F ring.

Initially the dust-sized material drawn away from the ring appears to form a streamer pointing ahead of Prometheus in its orbit. (All orbital motion is towards the right in the movie.) Over time, the streamer falls increasingly farther behind Prometheus because material in the F ring is orbiting slower than the moon. The streamer gets longer and a darker "channel" starts to be seen (to the left of the streamer in the movie).

The creation of such streamers and channels occurs in a cycle that repeats each Prometheus orbit: when Prometheus again reaches apoapse, it draws another streamer of material from the F ring. But since Prometheus orbits faster than the material in the ring, this new streamer is pulled from a different location in the ring about 3.2 degrees (in longitude) ahead of the previous one.

In this way, a whole series of streamer-channels is created along the F ring. In some observations, 10 to 15 streamer-channels can easily be seen in the F ring at one time (see Shaping the Drapes (http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=95)). Eventually, a streamer-channel disappears as shearing forces (i.e., Keplerian shear) act to disperse the constituent dust particles.

The movie shows just under half of a complete streamer-channel cycle. The dark frames in the movie represent the period during which Prometheus and the F ring pass through Saturn's shadow.

The images in the movie were acquired by the Cassini spacecraft narrow-angle camera on Nov. 23 and 24, 2006. The movie sequence consists of 72 clear spectral filter images taken every 10.5 minutes over a period of about 12.5 hours.

The original images were cropped to show only the region around Prometheus and the nearby portion of the F ring. The movie covers the region between 138,000 and 142,000 kilometers (86,000 and 88,000 miles) radially from Saturn and 1 degree in longitude from Prometheus on each side. Each frame was reprojected such that the vertical axis represents distance from Saturn and the horizontal axis represents longitude around Saturn. Image scale is 10 kilometers (6 miles) per pixel in the vertical direction; the images cover 0.005 degrees of longitude in the horizontal direction. Because of the reprojection, the F ring appears straight, rather than slightly curved, as it otherwise would.

Since the F ring has an elliptical shape, its radial distance from Saturn varies by about 1,000 kilometers (620 miles) around the ring. This accounts for the apparent vertical movement of the ring over the course of the movie. Only a very small part of the ring appears in each of the reprojected frames, so the difference in the ring's radial distance from left to right across any single frame is small enough as to be effectively unnoticeable.

See also this shot of Prometheus and Pandora for another view of the channels

http://www.universetoday.com/wp-content/uploads/2008/11/prometheus-and-pandor.jpg (http://www.universetoday.com/2008/11/11/when-moons-and-rings-collide/)

So the shepherds do their thing here... and apparently planets do it around other stars... Hubble just announced photos of an ExoPlanet around Fomalhaut (25ly away)...

http://farm4.static.flickr.com/3001/3026603168_a57722cf33_o.jpg (http://blogs.discovermagazine.com/badastronomy/2008/11/13/huge-exoplanet-news-items-pictures/)

Wo0t! :eek: :D

Moogs

2008-11-14, 10:04

Looks like a mandlebot image. Very cool!

curiousuburb

2009-01-02, 09:59

So in addition to updating the main Cassini mission site (http://saturn.jpl.nasa.gov/) in honour of the extended 'Equinox' mission...

Two new true-colour photo releases that are candidates for awesome desktop pictures (I've tried to use thumbs to limit scroll, but extra res is available).

Detailed labels of the rings and gaps
A Full Sweep of Saturn's Rings (with labels)
http://saturn.jpl.nasa.gov/multimedia/images/rings/images/IMG003370-br500.jpg

December 30, 2008 Full-Res: PIA11142 (http://photojournal.jpl.nasa.gov/catalog/PIA11142)

+ Unlabeled Version (http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3376)
Details of Saturn's icy rings are visible in this sweeping view from Cassini of the planet's glorious ring system.

This natural color mosaic, taken from 10 degrees below the illuminated side of the rings, shows, from left to right, radially outward from Saturn, the C ring (with its Colombo and Maxwell gaps); the B ring and the Cassini division beyond, with the intervening Huygens gap; the A ring (with its Encke and Keeler gaps); and, on the far right, the narrow F ring. The total span covers approximately 65,700 kilometers (40,800 miles).

Although it is too faint to be seen here, the D ring is located just to the left of the C ring.

It is interesting to compare this view with Expanse of Ice (http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=2792), which shows the unilluminated side of the rings. The difference in brightness of the B ring relative to the other rings is striking. When illuminated directly by the sun, the B ring appears brighter than the adjacent A and C rings; however, when viewing the unlit side of the B ring, the A and C rings appear brighter. This phenomenon occurs because the density of the B ring is greater than that of the A or C rings.

The mosaic was constructed from 45 narrow-angle-camera images -- 15 separate sets of red, green and blue images -- taken over the course of about four hours, as Cassini scanned across the rings.

The images in this view were obtained by NASA's Cassini spacecraft on Nov. 26, 2008, at a distance of approximately 1.1 million kilometers (700,000 miles) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 28 degrees. Image scale in the radial (horizontal) direction is about 6 kilometers (3.5 miles) per pixel.

And a 'family portrait' with 6 moons, including Titan
Saturn ... Four Years On
http://a52.g.akamaitech.net/f/52/827/1d/www.space.com/images/081230-saturn-rings-02.jpg

December 30, 2008 Full-Res: PIA11141 (http://photojournal.jpl.nasa.gov/catalog/PIA11141) <-- 4800x2653 version Wo0t!

As Saturn advances in its orbit toward equinox and the sun gradually moves northward on the planet, the motion of Saturn's ring shadows and the changing colors of its atmosphere continue to transform the face of Saturn as seen by Cassini.

This captivating natural color view was created from images collected shortly after Cassini began its extended Equinox Mission in July 2008. It can be contrasted with earlier images from the spacecraft's four-year prime mission that show the shadow of Saturn's rings first draped high over the planet's northern hemisphere, then shifting southward as northern summer changed to spring (see Serenity of Saturn (http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=1437) and Sliding Shadows (http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=2886) ). During this time, the colors of the northern hemisphere have evolved from azure blue to a multitude of muted-colored bands.

This mosaic combines 30 images -- 10 each of red, green and blue light -- taken over the course of approximately two hours as Cassini panned its wide-angle camera across the entire planet and ring system on July 23, 2008, from a southerly elevation of 6 degrees.

Six moons complete this constructed panorama: Titan (5,150 kilometers, or 3,200 miles, across), Janus (179 kilometers, or 111 miles, across), Mimas (396 kilometers, or 246 miles, across), Pandora (81 kilometers, or 50 miles, across), Epimetheus (113 kilometers, or 70 miles, across) and Enceladus (504 kilometers, or 313 miles, across).

NASA's Cassini spacecraft captured these images at a distance of approximately 1.1 million kilometers (690,000 miles) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 20 degrees. Image scale is 70 kilometers (43.6 miles) per pixel.

Earthbound observers will miss the Rings for a while, as orbital mechanics mean we see them almost edge on for a few months. Cassini to teh rescue. ;)

Kickaha

2009-01-02, 10:44

Earthbound observers will miss the Rings for a while, as orbital mechanics mean we see them almost edge on for a few months. Cassini to teh rescue. ;)

Let me guess, we can't get the mechanics to hold off for a bit. Probably a union shop. :p

;)

(Nice pics!)

AWR

2009-01-02, 11:35

Great posts, cs! Stunning stuff.

curiousuburb

2009-08-08, 08:34

On Aug 11th the Rings will 'vanish'. (http://saturn.jpl.nasa.gov/news/cassinifeatures/feature2009087/)

Saturn to Pull Celestial Houdini on Aug. 11
August 7,2009

In 1918, magician extraordinaire Harry Houdini created a sensation when he made a 10,000 pound elephant disappear before a mystified audience of over 5,200 at New York's famed Hippodrome theater. But a vanishing pachyderm is nothing compared to the magnificent illusion to be performed by our solar system's own sixth rock from the sun on Aug. 11. On that day, ladies and gentlemen, boys and girls, children of all ages, the planet Saturn, with no help from either Jupiter or Uranus, will make its 170,000-mile-wide ring system disappear.

How does a mere gas giant planet, without the benefit of a magic wand, smoke and mirrors, or even sleeves for that matter, manage to hide an estimated 35 trillion-trillion tons of ice, dust and rock fragments? Saturn itself, perhaps adhering to the magician's code never to reveal how a trick is performed, is not talking. But fortunately for us, dear friends, Linda Spilker, deputy project scientist for the Cassini Saturn mission at NASA's Jet Propulsion Laboratory in Pasadena, Calif., is not in the magician's guild.
http://saturn.jpl.nasa.gov/images/saturnseasons_250W.jpg
Since Saturn's axis is tilted as it orbits the sun, Saturn has seasons, like those of planet Earth -- but each of Saturn's seasons last for over seven years. The Hubble Space Telescope took the above sequence of images about a year apart. Starting on the left in 1996 and ending on the right in 2000. Image credit: NASA/Hubble
"Saturn has been performing the "ring plane crossing" illusion about every 15 years since the rings formed, perhaps as long as 4.5 billion years ago, so by now it is pretty good at it," said Spilker. "The magician's tools required to perform this trick are pure sunlight, a planet that wobbles, and a main ring system that may be almost 200-thousand miles wide, but only 30 feet thick."

... continues ...

On the upside, the optical effect means shadows will reveal new discoveries...

Cassini spots new moonlet (http://www.wired.com/wiredscience/2009/08/aturnmoonlet/)

http://www.wired.com/images_blogs/wiredscience/2009/08/cassiniring.jpg

NASA’s Cassini spacecraft has discovered a new object in Saturn’s rings.

By capitalizing on the angle of sunlight cast on the rings as the planet nears its August 11 equinox, Cassini captured the 25-mile long shadow cast on Saturn’s B ring by a tiny moonlet that is probably around 1,300 feet in diameter.

It’s no coincidence that the spacecraft’s rendezvous with the planet coincides with its equinox, which occurs twice a Saturn year, or every 15 Earth years. The mission was planned to take advantage of the 27 months during which the sun is directly over the planet’s equator at noon. This positioning causes any three-dimensional object to cast a long shadow and stand out.

Because Saturn’s main rings, A, B, C and D, are a scant 30 feet thick, Cassini’s cameras can’t even see them, which makes it tough to spot anything sticking out from them. The equinox is the only time these objects will be plainly visible.

Bryson

2010-02-23, 19:46

Wait, that's no moon. (http://www.nasa.gov/mission_pages/cassini/multimedia/N00037579.html)

http://www.nasa.gov/images/content/124461main_N00037579-516-300.jpg

Edit: Dammit! Low-res version of the same on page one of this thread! And I searched and everything. Move on, nothing to see here. Except a giant planet-destroying space station, obviously.

curiousuburb

2010-02-23, 20:40

How about Moby Dick (bonus anaglyph 3D version)

http://saturn.jpl.nasa.gov/images/PIA12548_full.jpg (http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20100219/)

Behold the Violent History of Saturn’s White Whale Moon

Like the battered white whale Moby Dick taunting Captain Ahab, Saturn’s moon Prometheus surges toward the viewer in a 3-D image from NASA’s Cassini spacecraft.

The image exposes the irregular shape and circular surface scars on Prometheus, pointing to a violent history. These craters are probably the remnants from impacts long ago.

Prometheus is one of Saturn's innermost moons. It orbits the gas-giant at a distance of about 140,000 kilometers (86,000 miles) and is 86 kilometers (53 miles) across at its widest point. The porous, icy world was originally discovered in images taken by NASA’s Voyager 1 spacecraft back in 1980.

Cassini’s narrow-angle camera captured two black-and-white images of the moon on Dec. 26, 2009, and the imaging team combined the images to make this new stereo view. It looks different from the 'egg-cellent' raw image of Prometheus obtained on Jan. 27 because that view shows one of the short ends of the oddly shaped moon. In this 3-D image, the sun illuminates Prometheus at a different angle, making the moon’s elongated body visible.

Meanwhile... on Enceladus (http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20100223/)...

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA11688-br500.jpg (http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3852)
Bursting at the Seams

February 23, 2010 Full-Res: PIA11688 (http://photojournal.jpl.nasa.gov/catalog/PIA11688)

Dramatic plumes, both large and small, spray water ice out from many locations along the famed "tiger stripes" near the south pole of Saturn's moon Enceladus. The tiger stripes are fissures that spray icy particles, water vapor and organic compounds.

More than 30 individual jets of different sizes can be seen in this image and more than 20 of them had not been identified before. At least one jet spouting prominently in previous images now appears less powerful.

This mosaic was created from two high-resolution images that were captured by the narrow-angle camera when NASA’s Cassini spacecraft flew past Enceladus and through the jets on Nov. 21, 2009. (For other images captured during the same flyby, see Enceladan Tectonics and Baghdad Sulcus in 3-D ). Imaging the jets over time will allow Cassini scientists to study the consistency of their activity.

The south pole of the moon lies near the limb in the top left quadrant of the mosaic, near the large jet that is second from left. Lit terrain seen here is on the leading hemisphere of Enceladus (504 kilometers, 313 miles across).

Cassini scientists continue to study the question of whether reservoirs of liquid water exist beneath the surface of the moon. See Baghdad and Cairo Sulci on Enceladus and Jet Blue to learn more.

The view was obtained at a distance of approximately 14,000 kilometers (9,000 miles) from Enceladus and at a sun-Enceladus-spacecraft, or phase, angle of 145 degrees. Image scale is 81 meters (267 feet) per pixel.

...

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/IMG003861-br500.jpg (http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3861)
Enceladus' Warm Baghdad Sulcus

February 23, 2010 Full-Res: PIA11696 (http://photojournal.jpl.nasa.gov/catalog/PIA11696)

In this unique mosaic image combining high-resolution data from the imaging science subsystem and composite infrared spectrometer aboard NASA’s Cassini spacecraft, pockets of heat appear along one of the mysterious fractures in the south polar region of Saturn’s moon Enceladus. The fracture, named Baghdad Sulcus, is one of the so-called “tiger stripe” features that erupt with jets of water vapor and ice particles. It runs diagonally across the image.

This mosaic, obtained on Nov. 21, 2009, shows a 40-kilometer (25-mile) segment of Baghdad Sulcus and illustrates the correlation between the geologically youthful surface fractures and anomalously warm temperatures recorded in the south polar region. It shows the highest-resolution data yet of the heat leaking from the moon’s interior along the tiger stripes.

The image shows that broad swaths of heat previously detected by the infrared spectrometer are confined to a narrow, intense region no more than a kilometer (half a mile) wide along the fracture. The thermal image also reveals that the strength of the thermal radiation varies considerably along the length of this fissure segment. The temperature along Baghdad Sulcus reached more than 180 Kelvin (about minus 140 degrees Fahrenheit).

This mosaic layers temperature data atop of a visible-light image and alignment of the two data sets is approximate. The mosaic is centered near 80 degrees south latitude and 30 degrees west longitude. The V-shaped valleys that distinguish Baghdad are about 500 meters (1,600 feet) deep. The 30-degree slopes that rise along the valleys appear to be coated with smooth-looking particulate deposits that are peppered with large ice blocks that can reach tens of meters (yards) in size. The smooth materials most likely represent ice grain fallout from active jets that erupt along this warm and active section of Baghdad. The ice blocks appear to be icy rubble that may have been exposed by scouring from the eruptions, seismic shaking, and down-slope settling of the finer ice particles.

The moon's south pole lies outside of the frame of the mosaic, in the darkness below what is shown here. The full-length of Baghdad Sulcus, one of the longest tiger stripes, stretches about 175 kilometers (109 miles) all the way across the south polar region. This high-resolution view focuses only on one end of the rift, in the hemisphere that always faces toward Saturn. The other end of Baghdad was in shadow when these images were obtained. See Enceladus Polar Maps - South Pole - October 2009 to see all of Baghdad Sulcus and the other tiger stripes.

... continues ...

:)

curiousuburb

2010-03-29, 19:22

Mimas isn't the Death Star... it's Pac-Man (http://www.nasa.gov/centers/goddard/news/features/2010/pac-man-mimas.html)

Goddard Instrument Aboard Cassini Spacecraft Sees 'Pac-Man' on Saturn Moon
03.29.10

The highest-resolution-yet temperature map and images of Saturn’s icy moon Mimas obtained by NASA’s Cassini spacecraft reveal surprising patterns on the surface of the small moon, including unexpected hot regions that resemble “Pac-Man” eating a dot, and striking bands of light and dark in crater walls.

http://www.nasa.gov/centers/goddard/images/content/436201main1_pacmanmimas-670.jpg (http://www.nasa.gov/centers/goddard/images/content/436202main_pacmanmimas-full.jpg)
The left portion of this image shows Mimas in visible light, an image that has drawn comparisons to the "Star Wars" Death Star. The right portion shows the new temperature map, which resembles 1980s video game icon "Pac Man." Credit: NASA/JPL/Goddard/SWRI/SSI
› Click for Larger image

“Other moons usually grab the spotlight, but it turns out Mimas is more bizarre than we thought it was,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “It has certainly given us some new puzzles.”

Cassini collected the data on Feb. 13, during its closest flyby of the moon, which is marked by an enormous scar called Herschel Crater and resembles the Death Star from “Star Wars.”

http://www.nasa.gov/centers/goddard/images/content/436203main1_pacmanmimasmulti-670.jpg (http://www.nasa.gov/centers/goddard/images/content/436204main_pacmanmimasmulti-full.jpg)
This figure illustrates the unexpected and bizarre pattern of daytime temperatures found on Saturn's small inner moon Mimas (396 kilometers, or 246 miles, in diameter). The data were obtained by the composite infrared spectrometer (CIRS) on NASA’s Cassini spacecraft during the spacecraft's closest-ever look at Mimas on Feb. 13, 2010. Credit: NASA/JPL/Goddard/SWRI/SSI
› Click for Larger image

Scientists working with the composite infrared spectrometer, which mapped Mimas’ temperatures, expected smoothly varying temperatures peaking in the early afternoon near the equator. Instead, the warmest region was in the morning, along one edge of the moon’s disk, making a sharply defined Pac-Man shape, with temperatures around 92 Kelvin (minus 294 degrees Fahrenheit). The rest of the moon was much colder, around 77 Kelvin (minus 320 degrees Fahrenheit). A smaller warm spot -- the dot in Pac-Man’s mouth -- showed up around Herschel, with a temperature around 84 Kelvin (minus 310 degrees Fahrenheit).

“Even though we can’t explain the observed pattern of surface temperatures on Mimas, the giant Herschel crater is a leading suspect,” said Dr. Mike Flasar, composite infrared spectrometer principal investigator from NASA Goddard Space Flight Center in Greenbelt, Md. “The energy of impact that created it several billion years ago has been estimated to be one-seventh of Mimas’s own gravitational energy. Anything much larger would likely have torn the moon apart. We really would like to see if there is also an anomalous temperature pattern on the other side of Herschel, which has not been observed so closely.”

The warm spot around Herschel makes sense because tall crater walls (about 5 kilometers, or 3 miles, high) can trap heat inside the crater. But scientists were completely baffled by the Pac-Man shape.

“We suspect the temperatures are revealing differences in texture on the surface,” said John Spencer, a composite infrared spectrometer team member based at Southwest Research Institute in Boulder, Colo. “It’s maybe something like the difference between old, dense snow and freshly fallen powder.”

Denser ice quickly conducts the heat of the sun away from the surface, keeping it cold during the day. Powdery ice is more insulating and traps the sun’s heat at the surface, so the surface warms up.

Even if surface texture variations are to blame, scientists are still trying to figure out why there are such sharp boundaries between the regions, Spencer said. It is possible that the impact that created Herschel Crater melted surface ice and spread water across the moon. That liquid may have flash-frozen into a hard surface. But it is hard to understand why this dense top layer would remain intact when meteorites and other space debris should have pulverized it by now, Spencer said.

Icy spray from the E ring, one of Saturn’s outer rings, should also keep Mimas relatively light-colored, but the new visible-light images from the flyby paint a picture of surprising contrasts. Cassini imaging team scientists didn’t expect to see dark streaks trailing down the bright crater walls or a continuous, narrow pile of concentrated dark debris tracing the foot of each wall.

The pattern may appear because of the way the surface of Mimas ages, said Paul Helfenstein, a Cassini imaging team associate based at Cornell University, Ithaca, N.Y. Over time, the moon’s surface appears to accumulate a thin veil of silicate minerals or carbon-rich particles, possibly because of meteor dust falling onto the moon or impurities already embedded in surface ice.

As the sun’s warming rays and the vacuum of space evaporate the brighter ice, the darker material is concentrated and left behind. Gravity pulls the dark material down the crater walls, exposing fresh ice underneath. Although similar effects are seen on other moons of Saturn, the visibility of these contrasts on a moon continually re-paved with small particles from the E ring helps scientists estimate rates of change on other satellites.

“These processes are not unique to Mimas, but the new high-definition images are like Rosetta stones for interpreting them,” Helfenstein said.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md., where the instrument was built.

Waka-waka-waka

curiousuburb

2010-11-03, 11:20

Saturn's rings model galaxy formation (http://www.wired.com/wiredscience/2010/11/saturns-rings-mini-galaxy/)

Click images for sources.

Oscillations at B Ring edge

Saturn’s largest ring appears to behave like a mini spiral galaxy. NASA’s Cassini spacecraft caught enormous waves sloshing back and forth across Saturn’s B ring, similar to waves believed to give galaxies their spiral shapes.

http://www.ciclops.org/media/ir/2009/5762_15502_0.gif (http://www.ciclops.org/view/5762/Oscillations_at_B_Ring_Edge)
This movie, made from images obtained by NASA's Cassini spacecraft of the outer edge of Saturn's B ring, reveals the combined effects of a tugging moon and oscillations that can naturally occur in disks like Saturn's rings and spiral galaxies.

The B ring is shown at the lower left of the frame, and its outer edge varies with time, moving in and out in this concatenation of 92 images, each taken about 6 minutes apart, over the span of 9 hours, 30 minutes. The Cassini Division, the division between the A and B rings once thought to be empty, dominates the upper right of the frame. The Huygens Ringlet runs across the middle of the frame from the upper left to lower right.

At its innermost radial distance, the B ring's edge is 117,470 kilometers (72,992 miles) from the center of Saturn. At its outermost radial distance, the B ring's edge is 117,670 kilometers (73,117 miles) from the center of Saturn. These variations amount to a difference of 200 kilometers (about 120 miles).

Cassini scientists have determined that the complicated radial variations in the B ring edge are caused by the presence of four scalloped patterns, all independently rotating around the ring. One pattern, with two lobes, is present because of the gravitational perturbations from the moon Mimas, which alter the ring particle orbits because of a repetitive configuration of particle and satellite orbital positions known as a Lindblad resonance; this pattern always stays fixed with respect to Mimas. The other patterns with one, two, and three lobes respectively, travel around the ring with differing speeds and are believed to be natural modes of oscillation of the ring in this vicinity, excited by a process known as "viscous overstability."

In this process, the small, random motions of the ring particles feed energy into a wave that propagates outward across the ring from an inner boundary, reflects off the outer edge of the B ring (which becomes distorted as a result), and then travels inward until it reflects off the inner boundary. This continuous back-and-forth reflection is necessary for these wave patterns to grow and become visible as distortions in the outer edge of the B ring.

In supporting these so-called "self-excited" modes, the outer edge of the B ring is behaving the way astronomers believe spiral galaxies behave. However, such modes are not directly observable in galaxies. Cassini's observations of the outer B ring edge constitute the first time such large-scale modes in a broad disk of material have been observed in nature.
“This is a major result,” said Cassini imaging team leader Carolyn Porco of the Space Science Institute. “Saturn’s rings are tiny tiny tiny compared to a galaxy, but we see the same physics.”

http://www.ciclops.org/media/ir/2009/5761_14377_0.gif (http://www.ciclops.org/view/5761/Galactic_Behavior_for_the_Outer_B_Ring)
Keeping a close watch on the outer portion of Saturn's B ring, NASA's Cassini spacecraft records the complex inward and outward movement of the edge of the ring. This ring movement resembles the suspected behavior of spiral disk galaxies.

The position of the outer edge of the B ring, shown here crossing the middle of the frame, varies with time in this concatenation of 301 images taken an average of 1 minute, 50 seconds apart, over the span of about nine hours. The total variation of the edge, from the innermost to outermost locations, is 200 kilometers (120 miles). The eccentric Huygens Ringlet, another very narrow ringlet discovered by Cassini, and the innermost of the bands of ring material in the Cassini Division, a low-density region once thought to be empty, all appear in the top of the frame.

Cassini scientists have determined that the complicated radial variations in the B ring edge are caused by the presence of four scalloped patterns, all independently moving around the ring. One pattern, with two lobes, is present because of the gravitational perturbations from the moon Mimas, which alter the ring particle orbits because of a repetitive configuration of particle and satellite orbital positions known as a Lindblad resonance; this pattern always stays fixed with respect to Mimas.

The other patterns with one, two, and three lobes respectively, travel around the ring with differing speeds and are believed to be natural modes of oscillation of the ring in this vicinity, excited by a process known as "viscous overstability." In this process, the small, random motions of the ring particles feed energy into a wave that propagates outward across the ring from an inner boundary, reflects off the outer edge of the B ring (which becomes distorted as a result), and then travels inward until it reflects off the inner boundary. This continuous back-and-forth reflection is necessary for these wave patterns to grow and become visible as distortions in the outer edge of the B ring.

In supporting these so-called "self-excited" modes, the outer edge of the B ring is behaving the way astronomers believe spiral galaxies behave. However, such modes are not directly observable in galaxies. Cassini's observations of the outer B ring edge constitute the first time such large-scale modes in a broad disk of material have been observed in nature.
The new observations also show two warped regions, including a tall arc of spiky peaks that rise almost two miles above the ring plane. These perturbations may have been sculpted by small moons that migrated across the ring disk, a process believed to be important in shaping planetary systems.

WIRED compilation video (http://link.brightcove.com/services/player/bcpid3698508001?bctid=656414855001)

Saturn’s most massive ring, the B ring, has baffled astronomers since the Voyager spacecraft flew by in 1980 and 1981. Those observations showed the B ring was sculpted into a flattened football shape with a sharp outer edge by the moon Mimas. But even in the Voyager images, it was clear the B ring was too complex and chaotic to be shaped by Mimas alone.

Now, in a new analysis published in the Astronomical Journal, thousands of Cassini images gathered over the course of four years have revealed three separate wave patterns that are not driven by any moons, but spring up spontaneously by drawing energy from the small, random motions of ring particles. The waves, which can be hundreds of miles long, keep themselves going by reflecting off the ring’s edges.

“Think of it like waves in a pool,” Porco said. If two kids are hopping up and down at either end of a pool, she says, the waves they send sloshing across the water will pass through each other and reflect off the edge of the pool.

In Saturn’s rings, the waves are more like compressions in a Slinky than water waves, but the physics is similar. “These waves just go back and forth, and keep reflecting until they finally grow large enough so that we can actually see them,” Porco said.

“Normally viscosity, or resistance to flow, damps waves — the way sound waves traveling through the air would die out,” said planetary ring expert Peter Goldreich of Caltech and the Institute for Advanced Study in Princeton, who was not involved in the new study, in a press release. “But the new findings show that, in the densest parts of Saturn’s rings, viscosity actually amplifies waves, explaining mysterious grooves first seen in images taken by the Voyager spacecraft.”

Cassini has also observed similar waves on smaller scales, with wavelengths around 300 feet. Computer models of galaxies and protoplanetary disks around other stars have shown similar randomly generated waves with proportionally larger wavelengths. But because those waves would take hundreds of millions of years to complete one slosh, astronomers can’t observe them directly.

“This is the first time we’ve seen these things in nature,” Porco said. “It underscores the deep, physical connection between what we’re studying at Saturn’s rings, and disk systems across the universe at a very large range of spatial scales.”

Cassini has also snapped pictures of sharp, stalagmite-like peaks at the edge of the B ring that made themselves known by throwing long spiky shadows (below).

http://www.wired.com/images_blogs/wiredscience/2010/11/Cassini-tall-peaks.jpg (http://www.ciclops.org/view/6480/The_Tallest_Peaks)
Vertical structures, among the tallest seen in Saturn's main rings, rise abruptly from the edge of Saturn's B ring to cast long shadows on the ring in this image taken by NASA's Cassini spacecraft two weeks before the planet's August 2009 equinox.

Part of the Cassini Division, between the B and the A rings, appears at the top of the image, showing ringlets in the inner division.

In this image, Cassini's narrow angle camera captured a 1,200-kilometer-long (750-mile-long) section arcing along the outer edge of the B ring. Here, vertical structures tower as high as 2.5 kilometers (1.6 miles) above the plane of the rings -- a significant deviation from the vertical thickness of the main A, B and C rings, which is generally only about 10 meters (about 30 feet).

Cassini scientists believe that this is one prominent region at the outer edge of the B ring where large bodies, or moonlets, up to a kilometer or more in size, are found. It is possible that these bodies significantly affect the ring material streaming past them and force the particles upward, in a "splashing" manner.

This image and others like it (see PIA11669) are only possible around the time of Saturn's equinox, which occurs every half-Saturn-year, or about every 15 Earth years. The illumination geometry that accompanies equinox lowers the sun's angle to the ring plane and causes structures jutting out of the plane to cast long shadows across the rings. The "season" of equinox allows shadows to appear on the rings in the months before and after equinox, but the actual equinox occurred August 11, 2009, as the sun shone directly edge-on to the ring plane.

This view looks toward the southern, sunlit side of the rings from about 32 degrees below the ring plane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 26, 2009. The view was acquired at a distance of approximately 336,000 kilometers (209,000 miles) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 132 degrees. Image scale is 2 kilometers (1 mile) per pixel.
The new study suggests this region of the rings contains small moons that compress the ring material like a soda can and force it upward. This idea is supported by the presence of at least one moonlet, caught during Saturn’s summer equinox when it cast a shadow across the rings.

These moonlets may have migrated across Saturn’s rings, and become trapped in a gravitational resonance with the larger moon Mimas. This process of migration and trapping is exactly how scientists believe the solar system achieved its current architecture.

In this way, Saturn serves as a nearby laboratory to study celestial structures on all scales, from planets to solar systems to galaxies.

“There are basically two shapes in the universe, there’s disks and there’s spheres,” Porco said. “Saturn’s rings allow us to understand one of the two main structures in the universe: a celestial disk system.”

“This is not just a slight addition, it’s something significantly new,” Goldreich told Wired.com. Goldreich and colleagues predicted the presence of these waves in 1985, but the Cassini observations provide the first proof.

“A lot of times, you don’t expect to be around to see whether you made a prediction that worked,” Goldreich said. “I was quite pleased to see it.”

Those 'stagmite' peaks are up to 2.5 km higher than the 10m thick ring plane! :eek:

Also posted this week...

Rings around a Crescent

http://s3.amazonaws.com/ciclops_ir_2010/6549_15847_2.png?AWSAccessKeyId=14V1KFXK26R9EA1V0Q 02&Expires=1288825678&Signature=acQPP91w%2FoOeLZGjLXWySaShuP0%3D (http://www.ciclops.org/view/6549/Rings_Around_a_Crescent)
A crescent Saturn appears nestled within encircling rings in this Cassini image.

Clouds swirl through the atmosphere of the planet. Prometheus (86 kilometers, 53 miles across) orbits between the main rings and the thin F ring, and this moon appears as a speck above the rings near the middle of the image.

This view looks toward the southern, unilluminated side of the rings from about 3 degrees below the ringplane.

The image was taken with the Cassini spacecraft wide-angle camera on Sept. 14, 2010 using a spectral filter sensitive to wavelengths of near-infrared light centered at 890 nanometers. The view was obtained at a distance of approximately 2.6 million kilometers (1.6 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 100 degrees. Image scale on Saturn is 151 kilometers (94 miles) per pixel.

Cassini... bringing the awesome, as always. :)

Moogs

2010-11-03, 16:48

Freaking incredible images. +1 Burb point.

curiousuburb

2010-11-26, 15:40

Oxygen detected in atmosphere of Saturn's moon... Rhea.

http://news.bbcimg.co.uk/media/images/50138000/jpg/_50138851_pia10494.jpg
(http://www.bbc.co.uk/news/science-environment-11834954)
Rhea, the second biggest moon of Saturn, has an atmosphere of oxygen and carbon dioxide, scientists say.

It is incredibly thin, however. The density of O2, for example, is probably about five trillion times less dense than the oxygen that blankets Earth.

The presence of an exosphere, as it is more properly called, was confirmed by instruments on the Cassini probe which orbits the ringed planet and its moons.

The discovery is reported in the online version of Science magazine.

Oxygen exospheres have been seen at Jupiter's moons Europa and Ganymede, but this is the first time such a detection has been made in the Saturnian system.

Presumably, this kind of thing is duplicated billions of times throughout the galaxy. This could be something happening all over the place”
Dr Ben Teolis
Southwest Research Institute

Ben Teolis and colleagues say the tenuous envelope around Rhea is maintained by high-energy particles that constantly bombard the moon's icy surface.

"As the magnetic field rotates around Saturn, particles carried in the field slam into the hemisphere of Rhea that's facing their flow," Dr Teolis from the Southwest Research Institute in San Antonio, US, told BBC News.

"They hit that hemisphere and break water molecules on the surface. The atoms are then rearranging themselves to make O2 molecules, which are sputtered from the surface by additional impacting particles."

It is an ongoing process. As fast as the oxygen is created, energetic processes around Rhea are whipping the O2 molecules out into space.

The mechanism driving the production of carbon dioxide is less obvious, say the researchers.

Some of it, like the O2, could be being produced as a result of high-energy particle impacts. Such CO2 could certainly result if organic compounds are present in the surface ice.

It is possible also that the carbon dioxide was made in deep sub-surface processes and the CO2 is slowly escaping the moon's body.

http://news.bbcimg.co.uk/media/images/50144000/jpg/_50144739_1954_5102_1.jpg
Rhea is Saturn's second-largest moon, at 1,528km across
It is thought to be composed of a mixture of ice and rock - a frozen dirty snowball
Previous efforts to try to identify an exosphere at Rhea using Earth telescopes and even the remote-sensing instruments on Cassini had failed.

Only by getting up close to Rhea could Cassini make a positive detection.

"What we've been able to do now with Cassini is actually fly through this atmosphere and measure it in situ - to 'sniff' and 'taste' it, and find out what it's made of," said co-author Professor Andrew Coates from the Mullard Space Science Laboratory, University College London, UK.

The probe's ion and neutral mass spectrometer (INMS) measured peak densities of oxygen of about 50 billion molecules per cubic metre . It detected peak densities of carbon dioxide of about 20 billion molecules per cubic metre (about 600 million molecules per cubic foot).

"All this suggests these kinds of exospheres may be very common," said Dr Teolis. "There are different moons at Saturn and at Uranus, for example, which should be massive enough to hold an atmosphere. And, presumably, this kind of thing is duplicated billions of times throughout the galaxy. This could be something happening all over the place."

Other good candidates at Saturn might include the moons Dione and Tethys. No close flybys of Tethys are planned in the remaining years of the Cassini mission, but the probe will get near enough to Dione in December 2011 to try to make a direct detection of an exosphere.

Cassini is a joint venture between the US space agency (Nasa), the European Space Agency (Esa) and the Italian Space Agency (ASI).

Its mission has been extended up until 2017 when it will be commanded to destroy itself by plunging into Saturn's atmosphere.

Not the next moon I would have predicted to have an exosphere, but still cool.

curiousuburb

2010-12-16, 08:36

Cassini spots potential Ice Volcano on Titan (http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20101214/)

PASADENA, Calif. – NASA's Cassini spacecraft has found possible ice volcanoes on Saturn's moon Titan that are similar in shape to those on Earth that spew molten rock.
Topography and surface composition data have enabled scientists to make the best case yet in the outer solar system for an Earth-like volcano landform that erupts in ice. The results were presented today at the American Geophysical Union meeting in San Francisco.

http://saturn.jpl.nasa.gov/images/PIA13695still_620x385.jpg
Flyover of Sotra Facula, Titan . Full-Res: PIA13695 (http://photojournal.jpl.nasa.gov/catalog/PIA13695)

QuickTime, screen size: 640x360 (48 MB) MPEG-4, screen size: 1280x720 (80 MB) QuickTime, screen size: 1280x720 (145 MB) Window Media Video (74 MB) Flash Video (18 MB) MPEG-4, screen size: 640x360 (29 MB) MPEG-4, screen size: 640x360 (http://saturn.jpl.nasa.gov/multimedia/videos/movies/20101210TitanCryovolcano-640.mp4)(37 MB) Window Media Video (http://saturn.jpl.nasa.gov/multimedia/videos/movies/20101210TitanCryovolcano-640.wmv) (44 MB)

This movie is based on data from NASA's Cassini spacecraft and shows a flyover of an area of Saturn’s moon Titan known as Sotra Facula. Scientists believe Sotra is the best case for an ice volcano -- or cryovolcano -- region on Titan. The flyovershows two peaks more than 1,000 meters (3,000 feet) tall and multiple craters as deep as 1,500 meters (5,000 feet). It also shows finger-like flows. All of these are land features that indicate cryovolcanism. The 3-D topography comes from Cassini’s radar instrument. Topography has been vertically exaggerated by a factor of 10. The false color in the initial frames shows different compositions of surface material as detected by Cassini’s visual and infrared mapping spectrometer. In this color scheme, dunes tend to look relatively brown-blue. Blue suggests the presence of some exposed ice. Scientists think the bright areas have an organic coating that hides the ice and is different and lighter than the dunes. The finger-like flows appear bright yellowish-white, like the mountain and caldera. The second set of colors shows elevation, with blue being lowest and yellow and white being the highest. Dunes here appear blue because they tend to occupy low areas. The finger-like flows are harder to see in the elevation data, indicating that they are thin, maybe less than about 100 meters (300 feet) thick.

http://saturn.jpl.nasa.gov/multimedia/images/moons/images/PIA13696-th200.jpg (http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4195)
This image shows the location of an area known as Sotra Facula on Saturn’s moon Titan. The black and white swaths show data obtained by the radar instrument on NASA’s Cassini spacecraft.
"When we look at our new 3-D map of Sotra Facula on Titan, we are struck by its resemblance to volcanoes like Mt. Etna in Italy, Laki in Iceland and even some small volcanic cones and flows near my hometown of Flagstaff," said Randolph Kirk, who led the 3-D mapping work, and is a Cassini radar team member and geophysicist at the U.S. Geological Survey (USGS) Astrogeology Science Center in Flagstaff, Ariz.

Scientists have been debating for years whether ice volcanoes, also called cryovolcanoes, exist on ice-rich moons, and if they do, what their characteristics are. The working definition assumes some kind of subterranean geological activity warms the cold environment enough to melt part of the satellite's interior and sends slushy ice or other materials through an opening in the surface. Volcanoes on Jupiter's moon Io and on Earth spew silicate lava.

Some cryovolcanoes bear little resemblance to terrestrial volcanoes, such as the tiger stripes at Saturn's moon Enceladus, where long fissures spray jets of water and icy particles that leave little trace on the surface. At other sites, eruption of denser materials might build up volcanic peaks or finger-like flows. But when such flows were spotted on Titan in the past, theories explained them as non-volcanic processes, such as rivers depositing sediment. At Sotra, however, cryovolcanism is the best explanation for two peaks more than 1,000 meters (3,000 feet) high with deep volcanic craters and finger-like flows.

"This is the very best evidence, by far, for volcanic topography anywhere documented on an icy satellite," said Jeffrey Kargel, a planetary scientist at the University of Arizona, Tucson. "It's possible the mountains are tectonic in origin, but the interpretation of cryovolcano is a much simpler, more consistent explanation."

Kirk and colleagues analyzed new Cassini radar images. His USGS group created the topographic map and 3-D flyover images of Sotra Facula. Data from Cassini's visual and infrared mapping spectrometer revealed the lobed flows had a composition different from the surrounding surface. Scientists have no evidence of current activity at Sotra, but they plan to monitor the area.

"Cryovolcanoes help explain the geological forces sculpting some of these exotic places in our solar system," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "At Titan, for instance, they explain how methane can be continually replenished in the atmosphere when the sun is constantly breaking that molecule down."

Cassini launched Oct. 15, 1997, and began orbiting Saturn in 2004. Saturn has more than 60 known moons, with Titan being the largest. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency (ASI). JPL manages the mission for NASA's Science Mission Directorate at the agency's Headquarters in Washington.

The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and ASI, working with team members from the U.S. and several European countries. The visual and infrared mapping spectrometer was built by JPL, with a major contribution by ASI. The visual and infrared mapping spectrometer science team is based at the University of Arizona, Tucson. JPL is a division of the California Institute of Technology in Pasadena.
For more information about the Cassini mission, visit: http://www.nasa.gov/cassini.

BBC story (with audio interview which may be UK only) (http://www.bbc.co.uk/news/science-environment-11996621)

curiousuburb

2011-03-09, 09:46

5.6k Saturn Photographic Animation from Cassini Images

http://photojournal.jpl.nasa.gov/jpegMod/PIA11141_modest.jpg (http://vimeo.com/11386048)

No CGI, all real images. An IMAX work in progress from the OutsideIn (http://www.outsideinthemovie.com/) project.

Ultimately, the film will recreate a journey through the solar system using only actual images taken by the robotic spacecraft exploring our solar system. Here, you can zoom towards Saturn, through the rings and fly past some of its moons.

Watch it full screen in HD and feel like you're there.

Shweet!

Moogs

2011-03-09, 10:57

It's beautiful but I don't understand how the ring images can possibly be real. The rings are made of dust and rocks and boulders, right?

But the pass-though makes it look like a completely uniform haze with no solid stuff floating around. Would they even fly the spacecraft through the rings (for the reason stated above)??

Also at one point in the IMAX part the ring has a very unnatural looking termination that doesn't seem to match the light source. Like a hard-edged "cut" that doesn't seem to have any natural fade to it or matching component on the other side of the planet (you can see it in the image above). What am I missing?

Maciej

2011-03-09, 12:16

What am I missing?

You're not the only one. I'm confused by all the stuff you posted above too. Maybe they flew it right through one of the gaps between the rings - they must be fairly tight to form such ring structures.

curiousuburb

2011-03-09, 14:12

Cassini actually flew through the rings during it's orbital insertion (in one of the gaps). It has since crossed the plane a few times.

The Cassini imaging team even made their own movie of a 2007 ring plane crossing.

http://saturn.jpl.nasa.gov/multimedia/images/videothumbnails/images/IMG002510-br500.jpg (http://saturn.jpl.nasa.gov/video/videodetails/?videoID=147)

Crossing isn't in a gap this time, but you still get a sense they're only a maximum of about 10 metres thick (often only dust sized), and see lots of moons on show.

More details on the rings can be found here (http://saturn.jpl.nasa.gov/science/index.cfm?SciencePageID=55)

curiousuburb

2011-04-05, 07:25

Ring 'ripples' caused by comet (http://www.bbc.co.uk/news/science-environment-12899961)

Scientists say that strange ripples observed in the ring systems of Saturn and Jupiter were caused by comets.

The ripples, which the researchers say resemble the undulations of corrugated metal, were detected in both Saturn's rings and in Jupiter's lesser-known rings.
http://news.bbcimg.co.uk/media/images/51943000/jpg/_51943851_pia11664_modest-1.jpg
Alternating light and dark bands in Saturn's C ring captured by the Cassini spacecraft in 2009

The ripples in Jupiter's rings are believed to have been caused by the comet Shoemaker-Levy 9, which struck the planet in 1994. Details are published in two separate papers in the journal Science.

The researchers analysed images of Jupiter's rings taken by the Galileo spacecraft in 1996 and 2000 and by the New Horizons probe in 2007. They also looked at images of Saturn's rings taken by the Cassini spacecraft during 2009.

What they found were undulations that the researchers liken to a corrugated tin roof, which when lit from a low angle, appear as alternating dark and light bands.

This corrugation was found across Saturn's entire C ring, stretching for thousands of kilometres. It appeared to be part of a similar pattern observed previously in the fainter D ring. At least two separate spirals were meanwhile detected in Jupiter's rings.

They researchers believe they were been caused by debris, most likely from a comet, impacting rings, and tilting them.

"The material passes through the ring and basically causes the entire ring to be slightly tilted with respect to the planet's equatorial plane, and then it shears out to form this spiral pattern," said Dr Matthew Hedman of Cornell University in New York.

"There was the eureka moment when we realised we had a smoking gun”

Dr Mark Showalter
SETI Institute
Over time, the corrugated spiral became more tightly wound, as the gravity of the planet pulled the rings back into alignment. However, completing the process could take decades, the researchers estimate.

The team was then able to rewind the process using mathematical models to give an estimated date of the impact event. For Saturn, they arrived at a point in 1983, but have not yet found a possible candidate comet.

With Jupiter, they detected at least two spirals and so possibly two impact events. When they wound back the process for one of the spirals, they reached a point in 1994, the same year of the Shoemaker-Levy 9 impact.

... continues

Thankfully, it wasn't a Son'a collector.
http://images1.wikia.nocookie.net/__cb20070625043303/memoryalpha/en/images/d/d7/Sona_collector_deployed_fore.jpg (http://memory-alpha.org/wiki/Son%27a_collector)

:p