The next step is to consider potential scenarios for forming methane. The Red Planet is a good place to start because its methane abundance is so low. If a mechanism cannot explain even this small amount, it would be unlikely to account for Titan’s much greater quantity. For a 600-year lifetime, a little over 100 metric tons of methane would have to be produced each year to maintain a constant global average of 10 ppbv. That is about a quarter-millionth the production rate on Earth.
As on Earth, volcanoes are most likely not responsible. Martian volcanoes have been extinct for hundreds of millions of years. Furthermore, if a volcano had been responsible for the methane, it would also have pumped out enormous quantities of sulfur dioxide, and Mars’s atmosphere is devoid of sulfur compounds. Extraplanetary contributions also appear minimal. Some 2,000 tons of micrometeoritic dust are estimated to reach the Martian surface every year. Less than 1 percent of their mass is carbon, and even this material is largely oxidized and hence an insignificant source of methane. Comets are about 1 percent methane by weight, but they strike Mars only once every 60 million years on average. Thus, the amount of methane delivered would be about one ton a year, or less than 1 percent of the required amount.
Could it be that a comet struck Mars in the recent past? It could have delivered a large amount of methane, and over time the abundance in the atmosphere would have declined to its present value. An impact of a comet 200 meters in diameter 100 years ago, or a comet 500 meters in diameter 2,000 years ago, could have supplied sufficient methane to account for the currently observed global average value of 10 ppbv. But this idea runs into a problem: the distribution of methane is not uniform over the planet. The time it takes to distribute methane uniformly vertically and horizontally is at most several months. Thus, a cometary source would result in a uniform methane distribution over Mars, contrary to observations.
Smoke in the Waters
That leaves us with two possible sources: hydrogeochemical and microbial. Either one would be fascinating. Hydrothermal vents, known as black smokers, were first discovered on Earth in 1977 on the Galápagos Rift [see “The Crest of the East Pacific Rise,” by Ken C. Macdonald and Bruce P. Luyendyk; Scientific American, May 1981]. Since then, oceanographers have found them along many other midoceanic ridges. Laboratory experiments show that under the conditions prevailing at these vents, ultramafic silicates—rocks rich in iron or magnesium, such as olivine and pyroxene—can react to produce hydrogen in a process commonly referred to as serpentinization. In turn, reaction of hydrogen with carbon grains, carbon dioxide, carbon monoxide or carbonaceous minerals can produce methane.
The keys to this process are hydrogen, carbon, metals (which act as catalysts), and heat and pressure. All are available on Mars, too. The process of serpentinization can occur either at high temperatures (350 to 400 degrees C) or at milder ones (30 to 90 degrees C). These lower temperatures are estimated to occur within purported aquifers on Mars.
Although low-temperature serpentinization may be capable of producing the Martian methane, biology remains a serious possibility. On Earth, microorganisms known as methanogens produce methane as a by-product of consuming hydrogen, carbon dioxide or carbon monoxide. If such organisms lived on Mars, they would find a ready supply of nutrients: hydrogen (either produced in the serpentinization process or diffusing into the soil from the atmosphere) plus carbon dioxide and carbon monoxide (in the rocks or from the atmosphere).
Once formed by either serpentinization or microbes, methane could be stored as a stable clathrate hydrate—a chemical structure that traps methane molecules like animals in a cage—for later release to the atmosphere, perhaps by gradual outgassing through cracks and fissures or by episodic bursts triggered by volcanism. No one is sure how efficiently the clathrates would form or how readily they would be destabilized.
See what we're tweeting about
6 Comments
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.