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Friday, January 16, 2009

Scientists identify cause of Methane on Mars

Methane on Mars
The findings appear in a paper in print online on Thursday by the journal Science. The scientists also announced the findings at a NASA news conference. Dr. Mumma had previously reported some of his answer at scientific meetings, but the Science paper is the first time they have appeared in a peer-reviewed journal.

Methane, the simplest of hydrocarbon molecules, with one carbon atom and four hydrogen atoms, is fragile in air. It falls apart when hit by ultraviolet radiation in sunlight. That means any methane in the Martian air must have been released recently.

When the 2003 methane emissions were reported in 2004 by three teams of scientists, the findings generated surprise and cynicism, because only two explanations appear plausible.

One is geothermal chemical reactions concerning water and heat like those in the hot springs of Yellowstone. But no signs of recent volcanism, or even any hot spots, have been marked on Mars.

The second is biological. On Earth, a class of microorganisms known as methanogens breathes out methane as a waste merchandise

Because of the trouble in the capacity, many scientists wondered whether methane was really there or whether all three teams had been misled by their data.

Dr. Mumma’s group used telescopes in Hawaii to examine the light reflected off Mars. Different molecules absorb different wavelengths of light, and the scientists reported seeing black lines in the spectrum consequent to methane as well as water vapor.

The concentrations in 2003 were densest over three regions known as Terra Sabae, Nii Fossae and Syrtis Major. The scientists said that mineralogy of the surface bedrock recommended that the bedrock might be covering gas-rich materials.

The scientists also detected methane in 2006, but the global measurement was half of what it had been in 2003, raising a second unknown. Ultraviolet light would obtain more than a century to destroy that much methane.

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