Yet this hypothesis has a shortcoming. Huygens data rule out an underground source of acetylene; this compound must ultimately come from methane in the atmosphere. Thus, it seems like a circular argument: to produce methane (by microbes), one needs methane. Moreover, the sheer abundance of methane on Titan is so immense that methanogens would have to work in overdrive to produce it, severely depleting the available nutrients.
In view of these obstacles, a biological explanation for methane is much less attractive on Titan than on Mars. Nevertheless, the hypothesis of habitability bears investigating. Some scientists argue that this moon might have been or still be habitable. It receives enough sunlight to turn nitrogen and methane into molecules that are the precursors to biology. An underground water-ammonia brine, with some methane and other hydrocarbons thrown in, could be a friendly environment for complex molecules or even living organisms. In the distant past, when the young Titan was still cooling off, liquid water may even have flowed on the surface.
Organic Food
One crucial measurement that could help determine the sources of methane on Mars and Titan is the carbon isotope ratio. Life on Earth has evolved to prefer carbon 12, which requires less energy for bonding than carbon 13 does. When amino acids combine, the resulting proteins show a marked deficiency in the heavier isotope. Living organisms on Earth contain 92 to 97 times as much carbon 12 as carbon 13; for inorganic matter, the standard ratio is 89.4.
On Titan, however, the Huygens probe measured a ratio of 82.3 in methane, which is smaller, not larger, than the terrestrial inorganic standard value. This finding argues strongly against the presence of life as we know it. To be sure, some scientists suggest that life could have evolved differently on Titan than on Earth or that the inorganic isotope ratio may be different there.
No one has yet determined the carbon isotope ratio for Mars. This measurement is challenging when the concentration of the gas is so low (one billionth of that on Titan). NASA’s Mars Science Laboratory (MSL) rover, scheduled to arrive at Mars in 2010, should be able to carry out precise measurements of the carbon isotopes in methane and possibly other organic materials. It will also study solid and gaseous samples for other chemical signs of past or present life, such as a very high abundance ratio of methane to heavier hydrocarbons (ethane, propane, butane) and chirality (a preference for either left-handed or right-handed organic molecules).
Tied up with these issues is the question of why organics seem to be missing from the surface of Mars. Even in the absence of life, meteorites, comets and interplanetary dust particles should have delivered organics over the past four and a half billion years. Perhaps the answer lies in Martian dust devils and storms and ordinary saltation (the hopscotching of windblown dust grains). These processes generate strong static electric fields, which can trigger the chemical synthesis of hydrogen peroxide. Being a potent antiseptic, hydrogen peroxide would quickly sterilize the surface and scrub out the organics. The oxidant would also accelerate the loss of methane locally from the atmosphere, thus requiring a larger source to explain the abundances observed in the Martian atmosphere.
In summary, methane serves as the glue that holds Titan together in some mysterious ways. The presence of methane on Mars is equally intriguing, not the least because it evokes visions of life on that planet. Future exploration of both bodies will seek to determine whether they were ever habitable. Although life as we know it can produce methane, the presence of methane does not necessarily signify the existence of life. So planetary scientists must investigate thoroughly the sources, sinks and isotopic composition of this gas, along with other organic molecules and trace constituents in both gaseous and solid samples. Even if methane is found to have no connection to life, studying it will reveal some of the most fundamental aspects of the formation, climate histories, geology and evolution of Mars and Titan.
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Add CommentWant to see some real closeups of Mars,plus life like critters-take a look at these Italian 100 foot off the surface of Mars- see roots,animals footprints etc: www.msss.com/moc_gallery/e07_e12/full_glf_non_map/e10/e1001841.glf
Reply | Report Abuse | Link to thisToreityerate, I suggest staining the atmosphere with a harmless dye the is sensitive to mehane like a gram stain. Use the dye to contrast and locate the sources of methane and any sinks that may explain where the methane gas is recycled. Different optical filters can visually id the sources of methane once the atmosphee is stained.
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Reply | Report Abuse | Link to thisBrilliant!!! After you have invented such a miracle dye that can stain gases in the atmosphere, maybe you can also invent a method to move the requisite millions of tons of that stuff to Mars.
Surely there are non-biological chemical reactions in the vast sub subsrface of the earth that produce methane. The "primitive" tribes along the Alieutian Ismuth between Alaska and Kamchatka lived along the end of the "Circle of fire"that curved around what is now the southern Berring SEa, and according to their descendents folk songs and myths, they named the semi-circled arewa the Farting Sea becasuse of the smell of the undersea effusians that they tapped by ceramic turbines to "energize their first industrial revolution about 11 Millenia ago at the end of the ice age and before the great Tunguska like explosion of a comet over the Arctic Ocean around the North pole that caused the tsunamis ande earth/ice quakes that emptied the Arctic ocean across the world, much through what is now the Bering Sea, denuding of life much of what is now the outer Aleutian chain of islandsislands and some islands such as St Lawrence --and in the other direction from the North Ple, around Iceland and the Isthmus of Faroe to northern Scotland, washing away in the procesws all the evidence of the world-wide industrtialization that was created at the end of the ice age by relying on ceramic turbines utilizing the methane eruptions from the rings of fire and other undersea volcanic sources of power.
Reply | Report Abuse | Link to thisThe point is that all that volcanic methane had to come from somewhere and although we call manatees "sea cows" there just we not millions of giant sea cows farting throughout the seas whose methane wan in some way sequestered into some subsurface bubble that farted gently until perturbed by an exploding comet and its consequential quakes and shifts of a quarter of the water in the world from the Arctic ocean down across EurASIa, North America and the North Atlantic and North Pacific as well as the Bering Sea that bore the brunt of the floods, equal to those that crossed from the Black and Caspian Seas, etc, cleared out the Dardanelles and flowed over what is now Turkey, across the later "Fertile Crescent" and over Lebanon into the great Valley of Middle Earth that is now the Mediterranian sea befor it carved out the Straits ofr Gibralter, met the floods from the North Atlantic ro inundate Atlantis before rushing across the Atlantic and Carribean Islands, washing away the Isthmusfrom Florida to Cuba and proceeding to cross the Mexican Sea (now the Gulf of Mexico and dumping its debris anong the Texas coast, forming what are now barrier islands off-shore from what it had formed as the Great South Texas Salt Sea, now almost all evaporated and covered and covered bysands liberated by winds over THE Continental Shelf and circled by the cedars of Lebanon brought across the Mediterranian Sea and Atlantic Ocean, and growing as if they had been natives around the last of the 4lakes left over from the Great South Texas Salt Sea whose salt was left by evaporation under the South Texas sun as a layer about a foot thick under the sandy soil about 25 feet down.
Surely there are non-biological chemical reactions in the vast sub subsrface of the earth that produce methane. The "primitive" tribes along the Alieutian Ismuth between Alaska and Kamchatka lived along the end of the "Circle of fire"that curved around what is now the southern Berring SEa, and according to their descendents folk songs and myths, they named the semi-circled arewa the Farting Sea becasuse of the smell of the undersea effusians that they tapped by ceramic turbines to "energize their first industrial revolution about 11 Millenia ago at the end of the ice age and before the great Tunguska like explosion of a comet over the Arctic Ocean around the North pole that caused the tsunamis ande earth/ice quakes that emptied the Arctic ocean across the world, much through what is now the Bering Sea, denuding of life much of what is now the outer Aleutian chain of islandsislands and some islands such as St Lawrence --and in the other direction from the North Ple, around Iceland and the Isthmus of Faroe to northern Scotland, washing away in the procesws all the evidence of the world-wide industrtialization that was created at the end of the ice age by relying on ceramic turbines utilizing the methane eruptions from the rings of fire and other undersea volcanic sources of power.
Reply | Report Abuse | Link to thisThe point is that all that volcanic methane had to come from somewhere and although we call manatees "sea cows" there just we not millions of giant sea cows farting throughout the seas whose methane wan in some way sequestered into some subsurface bubble that farted gently until perturbed by an exploding comet and its consequential quakes and shifts of a quarter of the water in the world from the Arctic ocean down across EurASIa, North America and the North Atlantic and North Pacific as well as the Bering Sea that bore the brunt of the floods, equal to those that crossed from the Black and Caspian Seas, etc, cleared out the Dardanelles and flowed over what is now Turkey, across the later "Fertile Crescent" and over Lebanon into the great Valley of Middle Earth that is now the Mediterranian sea befor it carved out the Straits ofr Gibralter, met the floods from the North Atlantic ro inundate Atlantis before rushing across the Atlantic and Carribean Islands, washing away the Isthmusfrom Florida to Cuba and proceeding to cross the Mexican Sea (now the Gulf of Mexico and dumping its debris anong the Texas coast, forming what are now barrier islands off-shore from what it had formed as the Great South Texas Salt Sea, now almost all evaporated and covered and covered bysands liberated by winds over THE Continental Shelf and circled by the cedars of Lebanon brought across the Mediterranian Sea and Atlantic Ocean, and growing as if they had been natives around the last of the 4lakes left over from the Great South Texas Salt Sea whose salt was left by evaporation under the South Texas sun as a layer about a foot thick under the sandy soil about 25 feet down.
Sorry, I want to see them but can't see them; the link don't work!
Reply | Report Abuse | Link to thisSorry for my duplicate posts above but I didn't think it had posted because it said my log on had failed. If there is a way to delete the duplicate, please let me know.