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Change we can believe in?

Posted By lukemeister On Friday, 16 January 2009 @ 21:45 In Space, Science | 1 Comment

NASA held an interesting press conference yesterday about the discovery of localized emissions of methane from Mars. [1] The discovery of Martian methane, using both ground-based telescopes and a spacecraft orbiting Mars, was reported in 2003, but [2] the detections weren’t certain. Now high-resolution infrared spectra taken by Michael Mumma at NASA/Goddard and colleagues, [3] reported online in Science, seems to provide definitive measurements. The CH₄ appears to arise from three regions near or within [4] Arabia Terra, [5] Nili Fossae, and [6] Syrtis Major. The most intriguing observation in the new study is that the atmospheric abundance of methane dropped by a factor of two between 2003 (northern summer on Mars) and 2006 (vernal equinox on Mars), possibly suggesting a seasonal cycle. Methane has a lifetime of centuries against destruction by ultraviolet light from the Sun, so there must be another sink, possibly involving reactions with [7] perchlorate or peroxide in the Martian soil.

On Earth most methane is generally thought to originate biologically, although it can also be produced through [8] serpentinization, which involves the reaction of minerals like [9] olivine and [10] pyroxene with water and carbon dioxide. Both biological and abiological origins for Mars’ methane are in play. If martian microbes exist, their metabolism might resemble that of [11] organisms found at 3 km depth in a gold mine in South Africa. Even if Martian methane originates abiologically, the new observations seem to imply that Mars shows a surprisingly high level of geological activity, as serpentinization on Earth is associated with [12] hydrothermal systems.

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URL to article: http://blog.bbbeard.com/2009/01/16/change-we-can-believe-in/

URLs in this post:
[1] The discovery of Martian methane, using both ground-based telescopes and a spacecraft orbiting Mars, was reported in 2003: http://www.cnn.com/2004/TECH/space/03/30/mars.methane/index.html
[2] the detections weren’t certain: http://www.sciam.com/article.cfm?id=methane-on-mars-titan&print=true
[3] reported online in Science: http://www.sciencemag.org/cgi/content/abstract/1165243
[4] Arabia Terra: http://en.wikipedia.org/wiki/Arabia_Terra
[5] Nili Fossae: http://en.wikipedia.org/wiki/Nili_Fossae
[6] Syrtis Major: http://en.wikipedia.org/wiki/Syrtis_Major
[7] perchlorate: http://www.sciam.com/blog/60-second-science/post.cfm?id=perchlorate-found-on-mar
s-makes-soi-2008-08-04
[8] serpentinization: http://en.wikipedia.org/wiki/Abiogenic_petroleum_origin
[9] olivine: http://en.wikipedia.org/wiki/Olivine
[10] pyroxene: http://en.wikipedia.org/wiki/Pyroxene
[11] organisms found at 3 km depth in a gold mine in South Africa: http://www.carnegieinstitution.org/news_releases/news_2006_1019.html
[12] hydrothermal systems: http://www.lostcity.washington.edu/science/chemistry/serpentinization.html

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