Monday, March 30, 2009

Life on Mars

I was watching a show on discovery channel; people were discussing if life could have first started on Mars and then "landed" on earth...(watch Into the Unknown with Josh Bernstein)

The scientific community only started to really look into this issue after president Bill Clinton in 1996 said there was such a possibility. This was probably after they were able to retrieve a Martian rock sample. (It has a very strange name. It was a combination of words and numbers. I think its this one).

The documentary then went on to actually reveal various researches that would actually prove life was indeed possible on Mars, and it could have originated from there. All of these researches could not have been triggered without a discovery on Mars. There was a discovery by one of those Mars missions which showed the possibility of ice formations under Mar's rocky surface. If life was ever observed by someone to thrive underground, you could rule out such life forms relying on sunlight for their energy needs. But then again, that is against our 1st and most important criteria for the existence of life - sunlight. (Anyway this is what I studied in my school).

But people have gone to extreme depths, and discovered that life does exist, here on earth. I can't remember what they called that particular organism, but they had classified it to be an extremophile. It seems that this particular specie gets its energy by some chemical reaction, (which is not fully understood as of present). It was an entirely new specie that had never been catalogued before. It was found in a remote undisclosed cave located in New Mexico, USA. Those scientists did not disclose the location as they fear contamination with foreign life forms - the ones we are exposed to all the time. So now you get the picture of how extreme this specie is...

Another Martian discovery was the evidence of frozen river beds of high salt concentration. Of which salt(s)? I don't know. But generally the assumption is that these beds are salty. This does show the possibility that the Martian surface had rivers very long time ago. Life was actually present on the surface of Mars! But the focus here is on those salty beds. This leads us to assume that there were river/lake beds that were highly saline. So people, here on earth, tried to investigate if life could survive in these high saline conditions. Since these river beds were on the surface, they were exposed to sunlight and hence this led to the possibility of photosynthesis being one of the ways organisms actually produced food for their energy needs. But even photosynthesis needs water. A highly saline environment would actually strip a cellular body of its water content. So how do such bodies live?

Well, here on earth, scientists discovered organisms that lived in similar environments. These organisms have special cell membranes. They are hard and virtually immune of reverse osmosis. So salt does not enter their system and disrupt it. Studies have also showed that the concentration of such organisms were high when sunlight was peak.

So there; all these are seemingly proof that life could have existed on mars. We don't see diversity in life forms on mars like that on earth because at present the conditions on mars do not support a very rich and diverse earth-like ecosystem. But one should guess how does life on mars reach earth?

Asteroids could have brought them in

Yes, and it is not something new. People have looked into the possibility of asteroids and/or comets bringing life to earth before. Here is a possibility of a foreign body from another planet being introduced into earth. There is evidence of craters on the mars surface suggesting that it was bombarded by asteroids before. The collision would have been so enormous that some Martian rocks escaped Mar's gravitational field and got caught in earth's gravitational field. This could have possibly made life "flourish".

So where does this leave Panspermia?

Panspermia suggests that life on earth could have originated because of seeds planted by other alien civilizations/life forms. We may never really know if this was how life was indeed started. Even if it was we would even go the depth of understanding how that life form came to existence. What’s accepted currently is the Theory of Chemical Evolution: life could have started due to numerous chemical reactions between stable/unstable compounds over time, and under some highly improbable conditions. The results of such reactions could have fortunately become stable. And even these stable compounds could have could have participated in more such reactions over time. Experiments have been done in this area - a popular example we learn through out text books at school is Miller's Experiment.
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