[The following is an excerpt from a paper about Mars from 2007. Some is no doubt out of date. Hopefully you'll still find the subject fascinating, as I continue to do.]
While NASA and others have been working hard to establish the case for water, many biologist and astrobiologists have been investigating as to what type of life may exist on Mars. What may be found could range from fossilized simple organisms to thriving microbial life forms, but they most definitely must demonstrate an ability to adapt to what we would call severe, extreme environments. On earth these creatures are not surprisingly known as extremophiles. They are “tiny microorganisms that thrive in the known world’s most hostile environments.”(10) One extremophile, Spirochaeta americana, is capable of surviving in an incredibly wide range of environments from the coolest temperatures of Antarctic ice to the extreme heated temperatures of volcanic vents. It has even been discovered in the waste of nuclear reactors.(11)
And there is more than just mere speculation. There have been slight indications that extremophile life may be causing some inexplicable observations. The presence of methane have some scientist posturing that a type of extremophile is active.(3) It is well known that methane cannot survive within the Martian atmosphere for very long (estimations place the length of time around a few hundred years). Yet consistent data has verified the presence of methane. Could it be that a microorganism similar to Earth’s Spirochaeta americana is replenishing the methane?
A far more puzzling discovery reveals the annual appearance and disappearance of Dark Dune Spots (DDSs). Though not as popularized as all the evidence for water, it is a truly fascinating phenomenon. Recorded by the MGS on the Southern Polar Region of the planet, spanning an area about 40 square kilometers, the DDSs appear in mid to late winter and apparently assist in the melting of the frost that has accumulated since autumn. The MGS was able to record a few of these seasonal changes and experts have analyzed and organized the data, a few finding it convincing enough to attribute the process to some kind of biological activity – what they call Mars Surface Organisms. The DDSs appear in late winter as soon as the first rays of sunlight rouse them. They assist in melting the frozen water surrounding them until the water itself evaporates and the MSOs are left defenseless (the ice acts as a shield) and they dissipate.(12,13) The following year the process begins again with variation – no two years being alike. See below a photograph illustrating the eerie image made by DDSs:
http://www.daviddarling.info/images/Marsspots2.jpg
So with all the evidence and theories mounting, NASA is currently in mid-stride developing an instrument that should be able to detect the faintest signs of life in the Martian soil. Called Urey: Mars Organic and Oxidant Detector, the machine is being tailored to interact with the complexities of the Martian environment. Urey’s sophisticated sensitivity will be 1,000,000 times greater than that of its predecessors, even capable of detecting amino acids to detail. “[It] will be able to distinguish between left-handed amino acids and right-handed ones,” said Allen Farrington, Urey project manager.(14) If Urey finds a very high percentage of homochirality (same handed amino acids), then the prospect of life is almost certain. On the other hand, if the percentage of left handed/right handed amino acids show to be roughly 50/50 (indicating the ratio of blind chance), then this would just as certainly mean that there has never been life on Mars. But should the percentages fall somewhere in the middle of these extremes, then it may indicate that life was once present.(14) The launch date has been set. Urey will set off in 2013, and NASA will once again flex its ingenuity and extend its reach across the dark expanse of space.
Will life be found on Mars? It is still far too early to tell, though with the rise of popular interest and funds, a dependable consensus should surface soon (soon being decades). It is doubtful though that the scientific community will be satisfied with a final answer until humans have made the long journey to step onto the Martian soil and see for themselves. Probably only then will all the experts agree, after humankind has conducted for itself a specialized, highly sophisticated experiment, and the matter will be closed. Then, with the red world beneath our feet, we will turn our gaze to Europa and Titan.
[I will add the works cited soon. I apologize but have them saved on another file.]
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