It rained on Mars - French study

Rxke · 2004-07-02 03:18:12

Not sure if this is news, it was already 'common knowledge,' but good to see some proof of theory

(EDIT: removed link, see Cindy's one instead.)

Palomar · 2004-07-02 09:57:10

*Hi Rik:

Having a difficult time downloading your link.

http://www.spacedaily.com/2004/04070118 … .html]This one is from spacedaily.com

Ironic history when correlated to Earth's (especially our theorized timing of beginning of life here).

It would be beautiful to see rainfall on Mars -- talk about the ultimate surreal experience. Rainstorms in the Chihuahuan Desert are eerily beautiful enough -- and some of our terrain reminds me quite a bit of Marsian vistas.

I created a short-lived thread in the Science & Technology folder a few months ago, wondering about the possibility of lightning strikes on Mars in its ancient past and if there were any way of detecting them (in future missions).

I wonder how thick and heavy Marsian clouds were then...if similar to our cumulonimbus clouds.

--Cindy

::edit:: http://www.newmars.com/forums/viewtopic … 52]Ancient Marsian Weather thread

Shaun Barrett · 2004-07-02 19:41:13

I was very happy to see this news item the other day because it tends to confirm my suspicions that Mars was once very much wetter than even the water-optimists think.
Actually, I'm surprised we haven't seen more comments on this intriguing paper. The idea of rainfall on Mars for about the first 1.5 billion years of its history is very exciting from a biogenesis point of view, or even from the angle that terrestrial life could easily have gained a foothold there via impact transfer.
Whether Mars gave rise to life first and it found its way to Earth, or vice versa, this latest information from French scientists gives us a much broader window of opportunity for life to have flourished during Mars' early history.

This, at least to me, may have a bearing on the activities of Spirit and Opportunity. As I've said before, I haven't given up hope that one of the MERs might serendipitously come across a macroscopic fossil.
If you accept that the climate on Mars was balmy enough for rainfall up to 3 billion years ago, you must surely give credence to the notion that large colonies of bacteria - along the lines of the large terrestrial 'mats' of blue-green algae - could well have thrived there. Terrestrial bacterial colonies gave rise to the stromatolites we all know and love, which are the best hard evidence we have of very early living organisms here on Earth. They're hard to find on Earth because so much of our crust has been recycled by plate tectonics and weathering over the eons but may be much more common on Mars.
Spirit and Opportunity might be lucky enough to sidle up to a perfect martian stromatolite any minute now!

In any case, it seems to me that it's becoming less and less likely Mars could be sterile. The evidence, while still only circumstantial, is now overwhelmingly against such a notion.
Look at the evidence:-
1) The chemical signature of life has been found in terrestrial rocks up to 3.8 billion years old (less controversial evidence exists from about 3.1 to 3.4 billion years ago).
2) Two-way impact transfer of essentially undamaged crustal material between Earth and Mars is an almost undisputed fact.
3) Conditions on Mars were conducive to life up to 3 billion years ago.
4) Opportunity has provided hard evidence that open bodies of water existed on Mars - only the depth and the persistence of these bodies is in question.
5) Dr. Gilbert Levin's Labeled Release Experiments on the Viking landers produced results it has proved impossible to duplicate by purely chemical means. The results, while controversial, fit a biological source much more closely than a chemical one. (Incredibly contrived and complex soil chemistry was proposed to explain the results, calling to mind the principle of Occam's Razor ... )
6) Mars is producing methane, which has recently been found in it atmosphere. While a volcanic source is possible, a biological source is seen as very much more likely. (The lack of metabolites in the martian environment was the chief stumbling block to my 'life-on-Mars' hypothesis. This discovery of methane removed nearly all remaining doubt in my mind.)
7) Once bacterial life gets a foothold anywhere, it's an all-but-impossible job to eliminate it. Ask anyone in charge of a hospital Operating Room!

There's now even less doubt in my mind that Mars harbours a biosphere - if not at the surface, then not far below it. And the odds against finding macroscopic fossils have just shortened considerably, in my opinion.

Shaun Barrett · 2005-05-08 17:56:06

I came across http://www.spaceref.com/news/viewpr.html?pid=16841]THIS INTERESTING ARTICLE today, which indicates Earth's environment may have been much more conducive to life considerably earlier than we thought.
The title is "New thermometer reveals wet conditions on earliest Earth", and the following excerpt represents the main thrust of it:-

"Our data support recent theories that Earth began a pattern of crust formation, erosion, and sediment recycling as early in its evolution as 4.35 billion years ago, which contrasts with the hot, violent environment envisioned for our young planet by most researchers and opens up the possibility that life got a very early foothold," said E. Bruce Watson, Institute Professor of Science and professor of geochemistry at Rensselaer Polytechnic Institute.

If Earth managed to achieve this potentially life-nurturing state only 250 million years after its formation, perhaps Mars did the same(?). And some authorities think Mars may have become more tectonically stable earlier than Earth anyway, due to faster cooling of its interior.

This thread, begun by Rik and encouraged along by Cindy (thanks guys! ), describes work by French scientists which suggests Mars may have had rainfall up until about 3 billion years ago.

If we combine these two lines of investigation (and speculation), we find that Mars may have had a 'window', between 4.35 billion and 3 billion years ago, during which its surface was conducive to life. That's 1.35 billion years!
Assuming an oxygen-rich atmosphere evolved there faster than it did on Earth (a pet hypothesis of NASA's Dr. Chris McKay), this seems to allow for the possibility that multi-cellular animal life could have developed; the window of opportunity was likely there, and so were the conditions.

Yet again I say, keep watching the MER images for anything that looks like macroscopic fossils! There just might be some there.

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#1 2004-07-02 03:18:12

Re: It rained on Mars - French study

#2 2004-07-02 09:57:10

Re: It rained on Mars - French study

#3 2004-07-02 19:41:13

Re: It rained on Mars - French study

#4 2005-05-08 17:56:06

Re: It rained on Mars - French study

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