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Forum » SpaceEngine » Science and Astronomy Discussions » Life on Mars (What do you think are the odds?)
Life on Mars
H2BroDate: Wednesday, 05.09.2012, 00:14 | Message # 16
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Mars may have been hospitable to life around 1 billion years ago, before the oxygen in its atmosphere binding to iron in the soil. Actually, the fact there was great deals of free molecular oxygen in the first place is some clue that microbes may have been actively producing it in the past, as oxygen rapidly reacts with other chemicals. Were it not for its ongoing production on earth we would lose our oxygen with some millions of years.

Apparently, there is a possibility that Mars has as much water as Earth but it is locked away in the soil and underground.

One of the more major problems for life on Mars is the absence of an active magnetic field to shield the intensity of solar and cosmic radiation. This radiation would tend to break down quite rapidly any sufficiently complex molecular chain reactions that one might call "life". It is possible that Mars had such a magnetic field in the past - planetary mag fields are still poorly understood.

Panspermia is difficult. The solar radiation pressure required to move a microbe from the upper atmosphere can push it to escape velocity from Earth but not from the solar system. Therefore cross-system fertilization of spores is unlikely via this method. Large scale planetary impacts have sufficient energy to vaporize most large organic compounds, but maybe not all.

The notion that life need arise on planets may be unfounded. Most organic compounds that form building blocks of life are thought to form in nebular molecular clouds prior to planetary formation. This also explains the right-handed chirality of organic life on earth - our Suns UV rays preferentially break down left-handed molecules, producing an abundance of right-handed ones. This would not occur to molecules on Earth as our magnetic field and atmosphere shield the majority of this radiation.

Most interesting, to me, is this: If different stars have different preferential breakdowns of chirality for molecules, there may be organic based, even DNA based lifeforms on other planets, that would be inedible to us. Our bodies only use right-hand molecules and left-hand molecules simply do not "fit" in our chemical process.

(btw chirality means the "handedness" of a molecule. each molecule, for example a protein, can be built in two configurations, the way we see it normally and a mirror image of that. All life on earth use "right-handed" molecules (so called because of how they polarize light)).
Best
H2Bro





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HarbingerDawnDate: Wednesday, 05.09.2012, 00:34 | Message # 17
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Quote (H2Bro)
If different stars have different preferential breakdowns of chirality for molecules, there may be organic based, even DNA based lifeforms on other planets, that would be inedible to us. Our bodies only use right-hand molecules and left-hand molecules simply do not "fit" in our chemical process.

This concept is take into account in the Mass Effect universe, where levo-amino acid based species cannot eat the same food as dextro-amino acid based species. Not a major plot device, but it is nice to see that those details are known and used in the entertainment industries.





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H2BroDate: Wednesday, 05.09.2012, 16:19 | Message # 18
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Quote (HarbingerDawn)
This concept is take into account in the Mass Effect universe


I only played ME2 for a bit, but I noticed they had a reasonably good explanation of the principle behind a quantum entanglement communications relay as well. It's nice when sci fi gives a head nod to the way things actually are instead of just flying by the seat of their pants, dont you think?





i3 370M 2.3Ghz ATI Radeon 5650 8GB DDR3 Win 7 (runs SE suprisingly well for a laptop!)
 
Forum » SpaceEngine » Science and Astronomy Discussions » Life on Mars (What do you think are the odds?)
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