Antimatter Man
Join Date: May 2004
Location: that interweb thing
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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. |
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¡Damned!
Join Date: May 2004
Location: Purgatory
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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. So it goes. |
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9" monochrome
Join Date: May 2004
Location: 🇦🇺
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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. |
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Hates the Infotainment
Join Date: May 2004
Location: NSA Archives
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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! ...into the light of a dark black night. |
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Antimatter Man
Join Date: May 2004
Location: that interweb thing
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including revised suppositions as to where the colliding body came for. |
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¡Damned!
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Hates the Infotainment
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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.
...into the light of a dark black night. |
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Antimatter Man
Join Date: May 2004
Location: that interweb thing
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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 TRACE Picture of the day (click for full 1024x830): Caption and info here |
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Hates the Infotainment
Join Date: May 2004
Location: NSA Archives
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Nnniiiiiice.
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Antimatter Man
Join Date: May 2004
Location: that interweb thing
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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. Quote:
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Last edited by curiousuburb : 2004-06-25 at 14:40. |
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Antimatter Man
Join Date: May 2004
Location: that interweb thing
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And if this ain't the spitting image of an Creative Sun God.... While the left menu link to movies leads primarily to grayscale versions, the POD Archive pages have some colour movies too. Rain Solar Tornadoes Filaments decay in magnetic arcades in Bastille Day Slinky Shit. Now I have to start a *Sun* Exploration Thread. |
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Hates the Infotainment
Join Date: May 2004
Location: NSA Archives
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That figure actually looks kind of demonic to me... spooooky.
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hustlin
Join Date: May 2004
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It sounds nuts that they are passing this thing so close to the rings. I want to see the pictures.
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Antimatter Man
Join Date: May 2004
Location: that interweb thing
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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: details here 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. They've already measured interaction with Saturn's magnetosphere, and rotational audio. Last edited by curiousuburb : 2004-06-29 at 13:01. |
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Antimatter Man
Join Date: May 2004
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Live commentary for the Saturn Orbit Insertion is due to start at 1830 PST on NASA TV.
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¡Damned!
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10 minutes to Ring Plane Crossing......
I'm so excited!!! |
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Antimatter Man
Join Date: May 2004
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Cassini has survived the ascending Ring plane crossing.
Doppler confirms signal. SOI engine burn will start at 19:36 PST. |
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Antimatter Man
Join Date: May 2004
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Main Engine Burn!
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¡Damned!
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'High-Five'-ing space nerds are cute.
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Veteran Member
Join Date: May 2004
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Another 75 minutes... let's hope someone remembered to code up the endBurn() method...
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Antimatter Man
Join Date: May 2004
Location: that interweb thing
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end of burn within 1 second of nominal predict.
Successful Orbit Insertion! now for some photos... |
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Space Pirate
Join Date: May 2004
Location: Atlanta
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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!
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Space Pirate
Join Date: May 2004
Location: Atlanta
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jinx, you're it!
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¡Damned!
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Raw images coming down...
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¡Damned!
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Some very cool stuff! Can't wait until they get processed.
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Hates the Infotainment
Join Date: May 2004
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[cartman]Sweeeeet.[/cartman]
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Antimatter Man
Join Date: May 2004
Location: that interweb thing
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Cassini's first image of the rings (unprocessed).
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Antimatter Man
Join Date: May 2004
Location: that interweb thing
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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. 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. |
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¡Damned!
Join Date: May 2004
Location: Purgatory
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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?
So it goes. |
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