User Name
Password
AppleNova Forums » AppleOutsider »

The Official * Mercury * Exploration Thread


Register Members List Calendar Search FAQ Posting Guidelines
The Official * Mercury * Exploration Thread
Page 2 of 2 Previous 1 [2]  Thread Tools
curiousuburb
Antimatter Man
 
Join Date: May 2004
Location: that interweb thing
 
2011-03-19, 08:00

The solar panels are apparently 2/3 mirror, too.
  quote
curiousuburb
Antimatter Man
 
Join Date: May 2004
Location: that interweb thing
 
2011-06-22, 11:52

Messenger Spies Mercury in Detail

Quote:

An enhanced colour view shows the smoother northern volcanic plains on Mercury to have a different composition (yellow) to the surrounding material

The US space agency's (Nasa) Messenger spacecraft is starting to open up a whole new vista on the planet Mercury.

The probe went into orbit around the inner-most world in March, and has been relaying a stream of data ever since.

Its latest pictures from just a few hundred kilometres above the surface are expected to provide important new clues to the origin of the planet and its geological history.

Nasa believes much of what we thought about Mercury will need to be revised.

"We had many ideas about Mercury that were incomplete and ill-formed that came out of our three flybys with Messenger and the flybys in the 1970s by the first spacecraft to visit Mercury, Mariner 10," said Messenger principal investigator Sean Solomon of the Carnegie Institution of Washington, US.

"Many of those ideas are having to be cast aside as we see orbital data for the first time. We are confirming a few theories but many others are being cast into the dustbin of science."

Mercury: The inner-most planet
  • Mercury was visited first by the Mariner 10 probe in the 1970s; and by Messenger currently
  • The planet's diameter is 4,880km - about one-third the size of Earth
  • It is the second densest planet in Solar System; 5.3 times that of water
  • The Caloris basin is the largest known feature (1,300km in diameter)
  • Scientists speculate there is water-ice in the planet's permanently shadowed craters
  • Mercury's huge iron core takes up more than 60% of the planet's mass
  • It is an extreme place: surface temperatures swing between 425C and -180C
  • Mercury is the only inner planet besides Earth with global magnetic field
  • Messenger is the first spacecraft to go into orbit around the planet
  • Messenger has now returned more than 20,000 pictures, a great many at resolutions that finally allow scientists to begin a proper interpretation of surface features.

This is particularly true of the polar regions, where previous imagery was poor or even absent.

At the north pole, Messenger can discern a huge expanse of smooth plains some four million square kilometres in area - about half the size of the continental USA.

"From our more detailed look at this beautiful large unit of smooth plains, we're seeing all kinds of evidence for volcanism and tectonic deformation," explained Brett Denevi, a mission scientist from Johns Hopkins University Applied Physics Laboratory. "You can see 'ghost craters' that were impact craters that were later covered over by lava."

Messenger went to Mercury to prove or disprove a number of cherished theories.

One concerned a 20-year-old hypothesis, supported by radar observations from Earth, that suggested some polar craters might hide reserves of water-ice.

On the face of it this seems an extraordinary proposition given that surface temperatures on Mercury, certainly at the equator, can exceed 400C - hot enough to melt lead.

Comparison: Messenger is now producing much sharper views of polar regions than during the flybys
But without a thick atmosphere to trap heat, it is possible that permanently shadowed regions could stay cold enough to preserve ices for millions, if not billions, of years.

Messenger has begun testing this theory by deploying a laser altimeter to map the shape of craters at the poles - with some encouraging results. Already it has found a depression that is deep enough and dark enough to have the right conditions.

"Stay tuned," said Dr Solomon. "This is a very exciting hypothesis that has stayed with us for 20 years, and it has passed its first test with flying colours.

"We look forward to results from our geochemical remote-sensing instruments - the neuron spectrometer, in particular - which will demonstrate whether or not the material at the poles is likely to be water-ice on the basis of excess hydrogen."

Messenger's X-Ray Spectrometer (XRS) has been investigating the presence and abundance of different atomic elements in surface materials, and has established rapidly that the rocks have a distinct signature that sets Mercury apart from its planetary neighbours.

"What's clear here is that Mercury is not the Moon and it's not the Earth," explained Larry Nittler, also of the Carnegie Institution.

"The surface of Mercury occupies a fairly unique location on the diagram for the surfaces of terrestrial planets. It's got lower aluminium and more magnesium relative to silicon, so it has a lower abundance of feldspar [minerals], and so it has clearly undergone a unique geological history."

A laser altimeter on Messenger is mapping the shape of craters in the planet's polar regions
XRS observations also reveal significant quantities of sulphur - at least a factor of 10 times higher than is seen at Earth. Why that should be is not clear, but probably points to the fact that Mercury formed in a different part of the Solar System to Earth where the raw materials for planet growth had a different composition.

Another new discovery concerns Mercury's magnetic field. The planet, along with Earth, is alone among the terrestrial planets in having a global magnetic field.

The probe has now identified a north-south asymmetry in this field which will allow far more charged particles streaming off the Sun to strike its south pole than its north.

These impacts are what lift atoms off the surface - sputtering, as scientists call it - to create Mercury's super-tenuous atmosphere (more properly described as an exosphere). The impacts also change the colour, reflectance and chemistry of the surface over time.

"What we thought on the basis of our flybys was that Mercury's magnetic field was a miniature version of Earth's magnetic field, produced by similar processes and with broadly similar geometry," said Dr Solomon. "Now we are in orbit, we can measure that magnetic field every day, and what we are seeing is that it is not a miniature of the Earth's field."
BBC story says it all, so I thought I'd paste the whole shebang.
  quote
curiousuburb
Antimatter Man
 
Join Date: May 2004
Location: that interweb thing
 
2015-05-01, 02:58

Farewell MESSENGER!
  • After almost 4000 days since launch and more than 4100 orbits of Mercury...
  • after exhausting it's main engine fuel and then cleverly adapting it's Helium thrusters to provide additional delta-vee...
  • MESSENGER was sent on a kamikaze dive for a close encounter with Mercury, grabbing data all the way down.

Final impact was calculated just north of Shakespeare Basin.


For Final Image details click pic below


Image size: approx 1 kilometer. Resolution: approx 2.1 meters/pixel

Details of Top 10 Science Results

and Top 10 Technology Innovations

Ice in your craters, ion spalling from the surface potentially due to "plasma tornadoes"...
You were cooler and hotter than we thought.

See you soon with Bepi-Columbo, hopefully.

All those who believe in telekinesis, raise my hand.
  quote
ronmexico
Senior Member
 
Join Date: Dec 2005
 
2015-05-01, 15:16

I appreciate the thoughtful posts on this mission Curiousuburb and can't believe almost 10 years have passed since this thread started!
  quote
Kickaha
Veteran Member
 
Join Date: May 2004
 
2015-05-01, 16:46

It's amazing, isn't it? I was there for the launch, courtesy of a buddy who was on the team.







And now, it has firmly completed its lithobraking procedure.
  quote
709
¡Damned!
 
Join Date: May 2004
Location: Purgatory
 
2015-05-01, 20:01

You are a shining light in the dim, dark universe, 'burb. Thanks for your constant amazing updates. Close to a 10 year thread! That's gotta be a record.

Now get your butt over to the New Horizons thread.

So it goes.
  quote
Moogs
Hates the Infotainment
 
Join Date: May 2004
Location: NSA Archives
 
2015-05-02, 19:10

You guys wait until the JWST launches. I'm going to pwn that thread. Been looking forward to it for years and it will be a little nerve-racking as the orbit is way the hell out there beyond where servicing missions can go.

...into the light of a dark black night.
  quote
Posting Rules Navigation
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Page 2 of 2 Previous 1 [2] 

Post Reply

Forum Jump
Thread Tools
Similar Threads
Thread Thread Starter Forum Replies Last Post
The Official *Saturn* Exploration Thread curiousuburb AppleOutsider 226 2017-09-15 06:26
Mars Exploration Thread Redux curiousuburb AppleOutsider 128 2016-03-14 05:16
The Official: Little Things that Rule™ thread. Moogs AppleOutsider 101 2013-08-14 14:24
The Official Dating Commentary™ Thread ShadowOfGed AppleOutsider 63 2006-05-08 10:13
An (official) welcome thread _Ω_ Feedback 1 2004-06-27 21:07


« Previous Thread | Next Thread »

All times are GMT -5. The time now is 04:03.


Powered by vBulletin®
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2024, AppleNova