Might Mars Contain Life?

stagmeister writes "According to the BBC, the Viking probes to Mars in the 1970s "detected strange signs of activity in the Martian soil - akin to microbes giving off gas," and that while those findings were not acknowledged as proof of life then, "in 1997, reached the conclusion ... that the so-called LR (labelled release) work had detected life." At the same time, the British are launching a probe to try to find life on Mars."

Comments

Comfort

[BWJones]

Well, I suppose if there is life on Mars, the likelyhood of more advanced life elsewhere in the universe is greater. That would certainly make me feel more comfortable as this universe is an awfully big place and to think we were all alone would be......scary.

Re:Comfort

[Ian Bicking]

While I agree with the above statement, there will ALWAYS be those who will refuse to believe or even claim that the discoveries were false. "Oh, some scientist must have forged the data" or "They just want to destroy religion" or "There was contamination".

To be fair, not all religions feel threatened by extraterrestial life. After all, the Catholic church is funding a (telescope?) project in conjunction with SETI -- so they can find aliens and then try to convert them to Catholocism. Terribly optimistic of those Catholics... a bizarre thought to think about them succeding.

Anyway, science and religion don't have to be at odds. In fact, they shouldn't be at odds -- religion and technology may often have a beef with each other, but science should just be seen as exploring God's creation.

what to look for?

[pleclair]

from the bbc article: "Mark Adler, deputy mission manager, said the main science objective was to understand the water environment of Mars not to search for life. He told BBC News Online: 'What we learnt from Viking is that it is very difficult to come up with specific experiments to look for something you don't really know what to look for.'"

I would have to agree, this is the tough part. The evidence is 20 years old from Viking, and its still being debated. Remember the martian rocks that "contained signs of life"? Me either.

. We're not even sure what to look for ... at least we're pretty damn sure what water looks like at this point ... these missions are expensive, I wouldn't waste a mission on something unlikely to succeed anyway.

Fascinating, Mr Spock

[wiggys]

If we can find life somewhere else out there it's going to be fascinating.

For example, is the life DNA based? All life on earth is DNA based, and if the life elsewhere isn't then we are going to learn a lot by studying it - it will be an using an entirely different mechanism to do essentially the same thing as DNA. How does it work? How did it evolve?

And if it *IS* DNA based then we need to find out if DNA is the logical conclusion of evolutionary biology... ie, I can imagine that intelligent life elsewhere have designed the same things we have (think "the wheel") because there are only so many ways you can do something. Therefore, is DNA (or something very similar) the only mechanism life can use to sustain itself? Or did the DNA originate from the same place as DNA on the earth? And if so, how?

Re:Fascinating, Mr Spock

[Christopher Thomas]

If we can find life somewhere else out there it's going to be fascinating.

For example, is the life DNA based? All life on earth is DNA based, and if the life elsewhere isn't then we are going to learn a lot by studying it - it will be an using an entirely different mechanism to do essentially the same thing as DNA. How does it work? How did it evolve?

There is evidence for at least _some_ cross-contamination between Earth and Mars occurring. If we find DNA or RNA based organisms there it may just be that they were seeded from here (or vice versa, back when Mars had water and a thicker atmosphere).

The place to look for *really* interesting things is environments that are isolated from ours, or that have conditions different enough that a different basic chemistry would be required.

Thermal vents on Io would be one option - there's lots of interesting sulphur-based chemistry upon which complex organisms could be based.

The oceans of Europa would also be an interesting spot - it's far from earth, and the potentially (earth-like-) life-bearing areas are beneath a thick crust of ice, so cross-contamination is less likely.

Cold worlds like tidally-heated moons of the outer gas giants would also be an interesting place to look. At those temperatures, life would a) run much more slowly and b) have to be based on lower-energy processes and substances with weaker binding forces for the available energy to be used to break down and rebuild biochemicals.

When we finally have probes capable of doing really detailed chemical and biological surveys of the outer solar system, we're going to find some very interesting things. Our own world shows us that microbes, at least, will show up wherever there's the energy and chemistry to support them.

contamination

[u01000101]

Only three have succeeded so far: the two Viking probes in the 1970s and Mars Pathfinder in 1997.

What are the chances those probes contaminated Mars with terrestrian microorganisms? Since the 1970's it was discovered life is more resilient than it was thought, with bacteria not only surviving, but thiriving, in mediums considered to be sterile - like in thermal water springs or nuclear reactor cores.

The meaning of "sterile" has changed a lot - see what measures NASA is preparing to take now for a (still theoretical) mission to Europa (Jupiter's satellite, for the challenged).

Peroxides != life

[pla]

From my understanding of the "signs of life" found by the Viking probes, they didn't find anything even remotely alive.

They found nothing more than solid peroxides (which tend to evolve oxygen when exposed to water), along with some unusual (but entirely explicable) iron-catalyzed reactions (remember why we call it the "red" planet).

Now, that doesn't disprove the presence of life, particularly a few meters below the surface. It does, however, present a VERY hostile surface environment (even ignoring the temperature and lack of an active planetary magnetic field) to life as we know it on Earth.


Hey, I'd like to find life there as much as the next guy... But it takes quite a leap of faith to interpret the Vikings' readings as "life". And science does not (or at least, should not) include any aspect of "faith".

Re:Carl Sagan said no

[tmortn]

Havn't read those ( read Pale Blue Dot ) but if I recall the nay sayers to the results claimed preasure/temperature change or some such in test chamber caused a change in state from the matian soil. IE say you have alkaseltser sitting on top of a cube of ice... no gas change. You scoop up the ice and alkazeltzer into a chamber with a different temperature.. one which melts the water, the liquid water then begins to react with the alkaseltzer causing a gaseus change ( what the experiment was looking for ).

Can't recall off the top of my head if it was the preasure/temp or both that changed.. but the environment in the experiment was not that of mars surface which caused the problem.