Autor Thema: Mars-Methan und Murchison  (Gelesen 1658 mal)

Offline karmaka

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Mars-Methan und Murchison
« am: Mai 30, 2012, 21:06:33 Nachmittag »
Mars-Methan und Murchison

Ein heute in NATURE veröffentlichtes Paper behauptet, dass das in der Marsatmosphäre gefundene
Methan zum Teil CM Chondriten wie Murchison entstammen könnte,
die einer ultravioletten Strahlung auf dem Marsoberfläche ausgesetzt waren.

Ultraviolet-radiation-induced methane emissions from meteorites and the Martian atmosphere
    Frank Keppler, Ivan Vigano, Ulrich Ott, Andy McLeod, Ivan Vigano, Marion Früchtl & Thomas Röckmann

Published online 30 May 2012

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11203.html

Zitat
Almost a decade after methane was first reported in the atmosphere of Mars1, 2 there is an intensive discussion about both the reliability of the observations3, 4—particularly the suggested seasonal and latitudinal variations5, 6—and the sources of methane on Mars. Given that the lifetime of methane in the Martian atmosphere is limited1, 6, a process on or below the planet’s surface would need to be continuously producing methane. A biological source would provide support for the potential existence of life on Mars, whereas a chemical origin would imply that there are unexpected geological processes7. Methane release from carbonaceous meteorites associated with ablation during atmospheric entry is considered negligible8. Here we show that methane is produced in much larger quantities from the Murchison meteorite (a type CM2 carbonaceous chondrite) when exposed to ultraviolet radiation under conditions similar to those expected at the Martian surface. Meteorites containing several per cent of intact organic matter reach the Martian surface at high rates9, and our experiments suggest that a significant fraction of the organic matter accessible to ultraviolet radiation is converted to methane. Ultraviolet-radiation-induced methane formation from meteorites could explain a substantial fraction of the most recently estimated atmospheric methane mixing ratios3, 4. Stable hydrogen isotope analysis unambiguously confirms that the methane released from Murchison is of extraterrestrial origin. The stable carbon isotope composition, in contrast, is similar to that of terrestrial microbial origin; hence, measurements of this signature in future Mars missions may not enable an unambiguous identification of biogenic methane.

 :hut:

Offline Andyr

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Re: Mars-Methan und Murchison
« Antwort #1 am: Mai 31, 2012, 09:20:33 Vormittag »
Schade dass ich keine kostenlose Möglichkeit mehr zu einem full access habe :-(

Offline SigurRosFan

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Re: Mars-Methan und Murchison
« Antwort #2 am: Mai 31, 2012, 10:52:24 Vormittag »
Ich hab dazu auch etwas zusammengefasst.

- Meteoriten-Ursprung von Mars-Methan?
Viele Grüße - Nico

MilliesBilly

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Re: Mars-Methan und Murchison
« Antwort #3 am: Juni 02, 2012, 14:25:16 Nachmittag »

Wie das Methan auch immer auf den roten Planeten gelangt sein mag: sensationell genug it immerhin der langerwartete Beweis, dass es Wasser auf dem Mars gibt:
http://apod.nasa.gov/apod/image/0504/WaterOnMars2_gcc.jpg

Offline karmaka

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Re: Mars-Methan und Murchison
« Antwort #4 am: Juni 02, 2012, 14:44:54 Nachmittag »
Ja, wirklich genau so haben wir uns das schon immer vorgestellt.  :laughing:

 :prostbier:

Martin

 

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