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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."
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.
"Well, then fire it up and show me what this..." (sigh)
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.
Saddle up: Riding with Robots
> Actually, the deal with the methane is this:
3 32 .pdf
e m/ mars_volcano_011113.html
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/2
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/solarsyst
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.
"Well, then fire it up and show me what this..." (sigh)
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.
"Well, then fire it up and show me what this..." (sigh)
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?
> is done by human beings
;) That would be the most colossal waste of money in history. That'd be like hiring Bill Gates to dust your living room.
:P
People On Earth.
We're not sending people over to Mars just to crunch numbers here
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.
"Well, then fire it up and show me what this..." (sigh)
Source: http://www.nasa.gov/home/hqnews/2005/feb/HQ_05052