Editor's Note: This story was originally published in the May 2007 issue of Scientific American; we're posting it now due to new findings released today pinpointing methane sources on Mars.
Of all the planets in the solar system other than Earth, Mars has arguably the greatest potential for life, either extinct or extant. It resembles Earth in so many ways: its formation process, its early climate history, its reservoirs of water, its volcanoes and other geologic processes. Microorganisms would fit right in. Another planetary body, Saturn’s largest moon Titan, also routinely comes up in discussions of extraterrestrial biology. In its primordial past, Titan possessed conditions conducive to the formation of molecular precursors of life, and some scientists believe it may have been alive then and might even be alive now.
To add intrigue to these possibilities, astronomers studying both these worlds have detected a gas that is often associated with living things: methane. It exists in small but significant quantities on Mars, and Titan is literally awash with it. A biological source is at least as plausible as a geologic one, for Mars if not for Titan. Either explanation would be fascinating in its own way, revealing either that we are not alone in the universe or that both Mars and Titan harbor large underground bodies of water together with unexpected levels of geochemical activity. Understanding the origin and fate of methane on these bodies will provide crucial clues to the processes that shape the formation, evolution and habitability of terrestrial worlds in this solar system and possibly in others.
Methane (CH4) is abundant on the giant planets—Jupiter, Saturn, Uranus and Neptune—where it was the product of chemical processing of primordial solar nebula material. On Earth, though, methane is special. Of the 1,750 parts per billion by volume (ppbv) of methane in Earth’s atmosphere, 90 to 95 percent is biological in origin. Grass-eating ungulates such as cows, goats and yaks belch out one fifth of the annual global methane release; the gas is a metabolic by-product of the bacteria in their guts. Other significant sources include termites, rice paddies, swamps,
leakage of natural gas (itself a result of past life) and photosynthetic plants [see “Methane, Plants and Climate Change,” by Frank Keppler and Thomas Röckmann; Scientific American, February 2007]. Volcanoes contribute less than 0.2 percent of the total methane budget on Earth, and even they may simply be venting methane produced by organisms in the past. Abiotic sources such as industrial processes are comparatively minor. Thus, detection of methane on another Earth-like object naturally raises the prospect of life on that body.
In the Air
That is what happened with Mars in 2003 and 2004, when three independent groups of scientists announced the discovery of methane in the atmosphere of that planet. Using a high-resolution spectrograph at the Infrared Telescope Facility in Hawaii and at the Gemini South Telescope in Chile, a team led by Michael Mumma of the NASA Goddard Space Flight Center detected methane concentrations in excess of 250 ppbv, varying over the planet and perhaps over time. Vittorio Formisano of the Institute of Physics and Interplanetary Science in Rome and his colleagues (including me) analyzed thousands of infrared spectra collected by the Mars Express orbiter. We found methane to be much less abundant, ranging from zero to about 35 ppbv, with a planetary average of approximately 10 ppbv. Finally, Vladimir Krasnopolsky of the Catholic University of America and his colleagues, using the Canada-France-Hawaii Telescope, measured a planetary average of about 10 ppbv. They could not determine the variation over the planet because of poor signal and spatial resolution.
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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.
Reply | Report Abuse | Link to this@gunondeer:
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.