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Mars crater may be belching organic gas; biological origin not ruled out

Dec. 17, 2014
Courtesy of Science
and World Science staff

Lev­els of the or­gan­ic gas meth­ane are per­i­od­ic­ally spik­ing at the Gale Crat­er on Mars—sug­gest­ing some­thing, pos­sibly some­thing alive, is cre­at­ing the sub­stance, sci­en­tists say.

Most of Earth’s meth­ane pro­duc­tion has a bi­o­log­i­cal or­i­gin, but there are oth­er ways meth­ane, the sim­plest or­gan­ic mol­e­cule, can arise nat­u­ral­ly. Or­gan­ic mol­e­cules are carbon-based and are es­sen­tial in­gre­di­ents for life.

This south­ward-looking view of Gale crater shows the Curi­osity ro­ver's land­ing area, out­lined in yel­low. (Courtesy JPL)


The new find­ings, from the NASA Mars rov­er Cu­ri­os­ity, are pub­lished this week in the re­search jour­nal Sci­ence.

In­ves­ti­ga­tors said the find­ings sug­gest that the meth­ane lev­el in Mars’ at­mos­phere at the 154-km (96 mile) wide crat­er is gen­er­ally low­er than mod­els pre­dict, but that it spikes of­ten. This im­plies the gas arises per­i­od­ic­ally from some near­by source, they added.

The sci­en­tists, from the NASA Je­t Pro­pul­sion Lab­o­r­a­to­ry in Pas­a­de­na, Ca­lif. and oth­er in­sti­tu­tions, used 20 months of da­ta col­lect­ed by in­stru­ments on Cu­ri­os­ity to gauge lev­els of the gas at crat­er, near where the rov­er land­ed. 

Their study found that the sta­ble, back­ground lev­el of at­mos­pher­ic meth­ane is less than half of what was ex­pected from known pro­cesses, such as the light-induced break­down of dust and or­gan­ic ma­te­ri­als de­liv­ered to Mars by me­te­orites. 

How­ev­er, the re­search­ers al­so found that this back­ground lev­el of meth­ane spiked about ten­fold, some­times over the course of just 60 Mar­tian days, which was sur­pris­ing be­cause the gas is ex­pected to have a life­time of about 300 years. The re­sults sug­gest that meth­ane is oc­ca­sion­ally pro­duced or vented near the crat­er, which is near the Mar­tian equa­tor, they added.

NASA or­i­ginally chose Gale Crat­er, which has a moun­tain in the mid­dle of it, as a land­ing site for the rov­er be­cause there were signs of wa­ter in the ar­ea. The crat­er is be­lieved to have formed with a me­te­or hit Mars in its early histo­ry, about 3.5 to 3.8 bil­lion years ago.

The an­nounce­ment comes just weeks af­ter anoth­er re­port con­clud­ing that a Mar­tian me­te­orite called Tissint con­tains or­gan­ic mol­e­cules of pos­sible bi­o­log­i­cal or­i­gin.


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Levels of the organic gas methane are periodically spiking near the Gale Crater on Mars—suggesting something, possibly something alive, is creating the substance, scientists say. Most of Earth’s methane production has a biological origin, but there are other ways methane, the simplest organic molecule, can arise naturally. Organic molecules are carbon-based and are essential ingredients for life. The new findings, from the NASA Mars rover Curiosity, are published this week in the research journal Science. Investigators said the findings suggest that the level of methane in Mars’ atmosphere at the 154-km (96 mile) wide crater is generally lower than models predict, but that it spikes often. This implies that the gas arises periodically by some nearby source, they added. The scientists, from the NASA Jet Propulsion Laboratory in Pasadena, Calif. and other institutions, used 20 months of data collected by instruments on Curiosity to gauge levels of the gas at crater, near where the rover landed. Their study found that the stable, background level of atmospheric methane is less than half of what was expected from known processes, such as the light-induced breakdown of dust and organic materials delivered to Mars by meteorites. However, the researchers also found that this background level of methane spiked about tenfold, sometimes over the course of just 60 Martian days, which was surprising because the gas is expected to have a lifetime of about 300 years. The results suggest that methane is occasionally produced or vented near the crater, which is near the Martian equator, they added. NASA originally chose Gale Crater, which has a mountain in the middle of it, as a landing site for the rover because there were signs of water in the area. The crater is believed to have formed with a meteor hit Mars in its early history, about 3.5 to 3.8 billion years ago. The announcement comes just weeks after another report concluding that a Martian meteorite called Tissint contains organic molecules of possible biological origin.