The Indirect Case For Life On Mars

Deinhard writes "Space.com is reporting that '[a] pair of NASA scientists told a group of space officials at a private meeting here Sunday that they have found strong evidence that life may exist today on Mars, hidden away in caves and sustained by pockets of water.' It is all based on methane signatures and not direct observation. Now plans for using the Genesis Device on Mars are out ... unless this is just a particle of preanimate matter caught in the matrix."

Comments

Nonbiological methane production

[nizo]

Methane can also be produced by volcanic activity. By all means keep coming up with ways to look for life on Mars, but most likely the only way we will find out for sure is to actually go there in person.

Re:Nonbiological methane production

[cephyn]

absolutely true. mod parent up. For the methane on mars, as far as we know, biological production is the BEST answer. It's not the only answer -- but right now, its actually the most likely.

Re:Nonbiological methane production

[Rei]

We also know of no liquid water trapped in pockets under Mars. So, your argument is invalid either way.

I'd call speculation on the origins of such a simple molecule without any evidence "really stretching it". Heck, few suspect that there's life on Titan, and yet the place is awash in methane. We don't know the source of it there, either (some speculate vast subsurface resevoirs). Why didn't it all react during it's formation? Titan, like Mars, has a reducing atmosphere (not an oxidizing atmosphere). There's insufficient free oxygen to react with everything, so in the absense of forces breaking it down (such as solar radiation in the upper atmosphere), it will last indefinitely.

On Mars, we have no clue what is going on beneath the surface. For all we know, the subsurface ices are packed with methane hydrates, or that there are giant hydrocarbon deposits. Just assuming that the source of methane is life without any other evidence but the methane itself seems like going so far out on a limb that you might as well just cut the limb off.

Re:Nonbiological methane production

[Rei]

> Actually, the deal with the methane is this:
Its lifetime in the atmosphere
> is ~ 350 (earth) years.

300-600. On Titan, it's about 10 million earth years - a ~20,000fold difference. However Mars has methane at 10.5 parts per *billion*, while Titan has 2-5% methane; methane on Titan is over *3 million* times more concentrated. Consequently, Mars is actually producing a rather small amount of inorganic methane compared to Titan. Titan has the advantage of being in deep-freeze, of course, but it's still an example of how huge quantities of methane can remain subsurface and be released steadily on a geologically inactive (presumedly) world.

> Thus, for the amount of methane detected, either there was recent (years ago,
> not Ma or even Ka) volcanic activity

Incorrect. There are many ways methane can be released inorganically; they're just not known by your average slashdotter. There's methane hydrates, which only need variations in temperature to outgas (which we know happen on Mars, and have happened to an extreme extent over its history). There are dozens of subsurface reactions apart from vulcanism that can produce methane - for example, it is an *expected* product of low temperature fluid-rock interaction; all it takes is enough low-level residual heat to melt ice:

http://www.lpi.usra.edu/meetings/lpsc2005/pdf/23 32 .pdf

However, even concerning vulcanism itself, the jury is still quite out. There is evidence of recent vulcanism on Mars, as you hinted to:

http://www.space.com/scienceastronomy/solarsyste m/ mars_volcano_011113.html

Contrary to how you tried to make it sound, 10 MY is very recent geologically. I see no reason to suspect that, if volcanoes have been erupting that recently, that it's suddenly going to peter out at the exact time (geologically speaking) that humans start observing the planet.

> Hydrocarbon deposits would require life to have existed in the past,

Not true. Hydrocarbons form in all sorts of circumstances; you can get short chains from UV interaction with methane alone. You can even have hydrocarbons formed from such basic reactions as the subduction of calcium carbonate and water in with Iron(II) oxide. Hydrocarbons are all over the place; for example, the Saturnian system is littered with organic "goo" (not just on Titan, but all over the place, from Phoebe to the rings).

People here just seem way too ready to grasp onto anything that could remotely be a product of life - even if it's something that forms inogranically all across our solar system, and is constantly outgassed from dead worlds.

Re:Nonbiological methane production

[Anonymous Coward]

You have based your criticism on an oversimplified understanding of the methane scenario on Mars. Here is the link supplied by the article which attempts to clarify the "methane signature" of interest to astrobiologists.

Re:Nonbiological methane production

[RKBA]

All planetary landers are assembled in clean rooms and sterilized prior to launch for this specific reason.

Re:Nonbiological methane production

[Rei]

> is done by human beings

People On Earth.

We're not sending people over to Mars just to crunch numbers here ;) That would be the most colossal waste of money in history. That'd be like hiring Bill Gates to dust your living room.

On Mars, people would only give two benefits: greatly improved latency, and slightly increased mobility. Neither of these are serious problems. The cost? A 50-fold increase in your mission budget. Hardly worth it. :P

Re:Nonbiological methane production

[gedhrel]

..? What you "know" is wrong. Ethanol doesn't have a left- and right- isomer. Ethanol is CH3 CH2 OH. There's only one way to make it. There's another compound with the formula C2H6O, and that's dimethyl ether: CH3 O CH3.

However, you're right in general that some biological processes only produce one particular stereoisomer.

But no, methane is just CH4. One version only.

Re:obligatory

[Anonymous Coward]

Dude, if you had put in a link you would have gotten modded up to +5. You were *so* close.

Re:Under Rocks?

[sighted]

They tried. It crashed. They may try again. Meanwhile, the rovers have to go to the equatorial region of the planet because they're powered by solar cells that require strong sunlight. And, while there is probably no life on the surface now, exposed layers of rock might yield clues about past life, if it ever existed.

Re:Another explanation

[mopomi]

We need a reason to be seeing the methane. It is destroyed in the atmosphere pretty quickly, so there needs to be a recharge mechanism.

Regardless of the mechanism, the discovery of methane in the atmosphere is a very important result. . .

Not the Future Legend, but the past...

[BeerCat]

Totally OT, I know, but there really were rats the size of cats (see about half way down), although the interviewee may have been turning Bowie's lyrics into fact. Or something.

Getting slightly back OT, the answer to the question "Is there life on Mars?" would seem to be a "definite maybe"

Re:Methane Lifetime on Mars

[Rei]

I was using the range provided by Sushil K. Atreya, Director of the Planetary Science Laboratory at the University of Michigan and keynote speaker at the International Mars Conference in Ischia, Italy, 19-23 September 2004. A single number is rather misleading, since there's a wide margin of error.

Positive Viking Lander Results

[north.coaster]

For some years now, the principle investigator for the 1976 Viking Lander Labeled Release Experiment has claimed that his experiment did find evidence of life on Mars. The problem is that the results from the other Viking experiments was inconsistent with this, so NASA decided that the LRE detected a non-biological chemical reaction.

Is this new data about methane consistent with the Viking LRE data?

Waiting for Mars Science Laboratory?

[MtViewGuy]

I think serious work on looking for current life on Mars will come when the Mars Science Laboratory lander arrives on Mars in 2010.

Unlike the current Mars Exploration Rovers, MSL is designed specifically to look for the possibility that lifeforms existed on Mars either in the past or even now. Also, because it will most likely use the same type of "nuclear" battery that powered the Galileo and Cassini spacecraft, it could run for two Earth years or more doing soil sampling, with the rover travelling well over 200 kilometers (124 miles) during its mission. It also means MSL can land and operate at higher latitude regions of Mars, which means the possibility of landing MSL near the polar cap regions.

NASA Press release

[bedessen]

RELEASE: 05-052

NASA Statement on False Claim of Evidence of Life on Mars

News reports on February 16, 2005, that NASA scientists from Ames Research Center, Moffett Field, Calif., have found strong evidence that life may exist on Mars are incorrect.

NASA does not have any observational data from any current Mars missions that supports this claim. The work by the scientists mentioned in the reports cannot be used to directly infer anything about life on Mars, but may help formulate the strategy for how to search for martian life. Their research concerns extreme environments on Earth as analogs of possible environments on Mars. No research paper has been submitted by them to any scientific journal asserting martian life.

Source: http://www.nasa.gov/home/hqnews/2005/feb/HQ_05052_ mars_claim.html