NASA Images Suggest Water Still Flows on Mars Options

[tglotch]

I see that Jim Bell had a nit to pick.

A little off-topic, but its worth noting that light-toned units on Mars often, but not always, exhibit different color properties than the surrounding terrains. Typically, they're redder. This has been a research interest of mine for a while, and presents an excuse to show a few pretty pictures.

Here are some THEMIS VIS examples from Aram, Aureum, and Iani Chaos, where the lighter-toned units are also "redder"--a quantity that is shown in the lower set of images as THEMIS VIS 540 nm band depth images. Anyway, these deposits are quite different from the gully light-toned material, but if that material has similar color properties to the above images, it would be indicative of an increased Fe3+ content.

[nprev]

Hate to say it, but I think it's gonna be a long time till we can conclusively answer the "L.O.M." question unless we get extremely lucky & identify a completely alien organism in a returned sample. (If hypothetical Martians are biochemically similar to Earth life, it will be much harder to distinguish them from contamination).

If there really isn't any life, it'll take centuries of in situ exploration to reach that conclusion definitively...

[JRehling]

It depends the hour you take the pictures! You're Marsostationary not Sunstationary
But you're right it's very far

If the slopes are facing away from the equator and the probe is over the equator, then the hour won't matter.

Technically, the term "stationary" does stipulate that the orbiter be directly over the equator. It is possible to have an inclined orbit that is synchronized for longitude that will bob between latitudes X north and X south. But that wouldn't give you continuous viewing of any particular perspective, so I don't see the advantage this would have over a much lower orbit with higher resolution. It would give you periodic viewings of the same point.

My notion was to have a 2-hour orbit that would also give you periodic viewings of the same point(s), but MUCH closer up.

[JRehling]

Hate to say it, but I think it's gonna be a long time till we can conclusively answer the "L.O.M." question unless we get extremely lucky & identify a completely alien organism in a returned sample. (If hypothetical Martians are biochemically similar to Earth life, it will be much harder to distinguish them from contamination).

If there really isn't any life, it'll take centuries of in situ exploration to reach that conclusion definitively...

The pessimistic outlook for LOM re: this discovery would be that the same areas on Mars may not be getting anywhere near enough repeat soakings to entail a habitat. There are areas on Earth where various lifeforms lie dormant until flash rains come, but that surely requires some favorable ratio, however slight of wet-to-dry. For example, 10 minutes wet every ten thousand years probably would not do the trick. Mars could be awfully cruel in this way.

My hypothesis on why the sun-facing slopes don't have gullies is that there is a finite subsurface reservoir and the sun-facing slopes already had their gullies and exhausted their supply a long time ago. In essence, I'm positing that the sun-facing slopes are like short-period comets and the sun-hidden slopes are like long-period comets.

[um3k]

Here is a link to the conference on Google Video:

http://video.google.com/videoplay?docid=34...61245&hl=en

[Guest_AlexBlackwell_*]

Next stop, Mars
By Adrienne So
Salon.com
December 8, 2006

This post has been edited by AlexBlackwell: Dec 8 2006, 04:17 PM

[Guest_AlexBlackwell_*]

NASA images, White Sands features support a wetter Mars
Andy Fell
Egghead Blog at UC Davis
December 7, 2006

[Guest_AlexBlackwell_*]

Here are some THEMIS VIS examples from Aram, Aureum, and Iani Chaos, where the lighter-toned units are also "redder"...

Thanks, Tim. Is this figure from the paper "Evidence for aqueous deposition of hematite and sulfate-rich light-toned layered deposits in Aureum and Iani Chaos," which you and A. Deanne Rogers have submitted to JGR-Planets?

[tglotch]

Thanks, Tim. Is this figure from the paper "Evidence for aqueous deposition of hematite and sulfate-rich light-toned layered deposits in Aureum and Iani Chaos," which you and A. Deanne Rogers have submitted to JGR-Planets?

yep.

[Guest_AlexBlackwell_*]

Hmmm...

I'm wondering if we should bone up Malin and Edgett's 2000 paper in Science, as well as Christensen's Nature paper.

Also, a 2003 PSRD release might be good reading.

I had a couple of inquiries about Christensen's paper from people who don't have access to Nature. You can download it from Christensen's blibliography page - specifically, the 301 Kb PDF.

As for Malin and Edgett's paper, I believe that the full text to all papers in Science are freely available online after a year, so that particular paper should be accessible.

[CosmicRocker]

Oh shucks...I have access to some online journals, but Science is out of my reach. I have tried mostly every trick in my book to locate a copy of that file, but still came up short. Living 90+ miles from the nearest library that is likely to have a subscription is one of the problems I face while living on the edge of civilization. I so hoped I would be able to read it without a 12 month wait.

Oh well. I guess a drive to a large city is in my future.

The water stuff has grabbed everyone's attention, but the new calibration point for the recent cratering rate is also noteworthy.

[tty]

Oh shucks...I have access to some online journals, but Science is out of my reach. I have tried mostly every trick in my book to locate a copy of that file, but still came up short.

It isn't. You can access most content older than 12 months (including Malin & Edgetts paper) for free, but you have to register as a user first. Details at:

http://www.sciencemag.org/about/access.dtl


tty

[SteveM]

Sorry to add another bit to the water discussion, but I saw a version of this in a Christmas catalogue and couldn't quite resist the temptation.

Little Willie was a chemist.
Little Willie is no more.
For what he thought was H2O,
Was H2SO4.

Steve

[Julius]

Well,if you followed the press briefing towards the end of it,Mike Malin himself sort of hinted that mars scientists could be still getting it wrong as regards the geochemistry of the gully flows.So there you may have a point Steve!

[djellison]

I knew it as

"Johnny Brown whent to school
but now he is no more
For what he thought was H2O
Was really H2SO4"

Doug