Mars: the race for life (Part I)

[The following is an excerpt from a paper I wrote on Mars and the speculation as to whether life could exist on Mars. This was in 2007, but hopefully still applicable.]

Questions and theories to the origin of life inevitably cause one to muse, regardless of your belief system, on what rare circumstances may belong to this planet. The race to space, though undoubtedly driven by economic and ideal motives, in the end, was an expression of an even deeper curiosity: is life on earth indeed the jewel of the cosmos? Until relatively recent, it was not uncommon for individuals to imagine that life could exist in abundance on various planets within our own solar system, especially on Mars. H. G. Wells simply transcribed into popular tale what was broadly conceived as possible by the late 19th century – that Mars contained intelligent life. In 1950 Ray Bradbury published the Martian Chronicles, imagining a Mars that had, in the distant past, teemed with life far more advanced and civilized than earth. Even as late as 1976 Carl Sagan boasted that the question to be answered by the Viking landers was not if they would find life, but what type.(1)

But the progress of technology has since sobered these imaginations. For the cold, calculating eyes of satellite, lander, and probe have shown us that the surface of Mars, and all the planets which they have scoped, are bereft of signs of life. Nonetheless, the march of science has continued, and advances in biology and chemistry have increased our understanding of the building blocks of life, life’s flexibility, and that some extreme environments once thought to be completely hostile, are able to support life. Consequently, hope that life may yet be found has endured, even if this hope has been demoted from one time intelligent life to crawling creatures to now simply microbes identifiable only with instrumentation. This enduring hope is the prime motivator behind NASA’s ongoing commitment to the race for life on our red neighbor.

Questions concerning the planet’s relationship with water are numerous to be sure–primarily because all known types of life on earth share a universal trait: dependence on water.

So where are we in our trek to finding water on Mars? The evidence is fairly convincing that water once covered much of the Martian surface. Villis Marineris is a well-known canyon system that many believe was at one time filled with water. The amount is staggering: it would cover the entire Amazon basin.(1) That much water would be more than enough to give life a starting chance. But what about the length of time? In some regions there are indications that fluids sat for a very long time. Scientists draw these conclusions from the chemical reactions apparent in rock formations.(7) Whether or not these fluids were largely composed of water, is still to be confirmed.

The evidence for water only begins there. In 2004 the Mars rovers Opportunity and Spirit landed on opposite ends of the globe and each began their dutiful search for indications of water. Opportunity, the more fortunate of the two, landed in a shallow crater of exposed bedrock. “We got lucky,” said Steve Squyres of Cornell University, “Tiger Woods couldn’t do this. We went right into it…the beauty of it is that the crater walls expose materials that we wouldn’t otherwise see.”(8) He was referring to the fine layers they observed running through the rock, suggesting the possibility that the exposure was sedimentary rock, formed on the floor of an ancient sea. After examining the rock, Opportunity found that it was as much as 40% sulfate salts, indicating that salt water had at one time covered the area and after evaporation, left salt components behind. The long arm of NASA had reached across the 35 million mile span and tested the soil for evidence of water, and the test proved positive.

Two years later more evidence for water appeared, only this time the evidence suggested that water might currently be on the planet, running underground. The Mars Global Surveyor (MGS), before it went silent about two years ago, had captured photos of the planet’s surface for seven years. Naturally, given the amount of time, many of these areas were retakes. When comparing the ‘before’ and ‘after’ photos, some experts believe that the evidence of flowing water is very high. The following photographs illustrate this:

http://nssdc.gsfc.nasa.gov/planetary/image/noachis_gullies.jpg

http://www.crystalinks.com/marswater1206.jpg

The theory is that some water seeps up through cracks and gets frozen just behind the surface for some time. The pressure builds and eventually the water bursts out through the surface. Some estimate from the photos taken that the amount of bursting water ranges from five to ten Olympic size swimming pools. It then runs in streaks over the sand and, quickly evaporating, often leaves behind it white trails of either salt or frost.(9)

[I apologize that I haven't added the sources. They're saved on another file and will do so soon.]

Mars: the race for life (Part II)

[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.]