Life on Mars theory boosted by new methane study

Dec 08, 2009
Mars. Image: NASA

Scientists have ruled out the possibility that methane is delivered to Mars by meteorites, raising fresh hopes that the gas might be generated by life on the red planet, in research published tomorrow in Earth and Planetary Science Letters.

Methane has a short lifetime of just a few hundred years on because it is constantly being depleted by a chemical reaction in the planet's atmosphere, caused by sunlight. Scientists analysing data from telescopic observations and unmanned space missions have discovered that methane on Mars is being constantly replenished by an unknown source and they are keen to uncover how the levels of methane are being topped up.

Researchers had thought that meteorites might be responsible for Martian methane levels because when the rocks enter the planet's atmosphere they are subjected to intense heat, causing a chemical reaction that releases methane and other gases into the atmosphere.

However, the new study, by researchers from Imperial College London, shows that the volumes of methane that could be released by the meteorites entering Mars's atmosphere are too low to maintain the current atmospheric levels of methane. Previous studies have also ruled out the possibility that the methane is delivered through volcanic activity.

This leaves only two plausible theories to explain the gas's presence, according to the researchers behind today's findings. Either there are microorganisms living in the that are producing methane gas as a by-product of their metabolic processes, or methane is being produced as a by-product of reactions between and water.

Co-author of the study, Dr Richard Court, Department of Earth Science and Engineering at Imperial College London, says:
"Our experiments are helping to solve the mystery of methane on Mars. Meteorites vaporising in the atmosphere are a proposed methane source but when we recreate their fiery entry in the laboratory we get only small amounts of the gas. For Mars, meteorites fail the methane test."

The team say their study will help NASA and ESA scientists who are planning a joint mission to the red planet in 2018 to search for the source of methane. The researchers say now that they have discovered that meteorites are not a source of Methane on Mars, ESA and NASA scientists can focus their attention on the two last remaining options.

Co-author, Professor Mark Sephton, Department of Earth Science and Engineering at Imperial College London, adds:
"This work is a big step forward. As Sherlock Holmes said, eliminate all other factors and the one that remains must be the truth. The list of possible sources of is getting smaller and excitingly, extraterrestrial life still remains an option. Ultimately the final test may have to be on Mars."

The team used a technique called Quantitive Pyrolysis-Fourier Transform Infrared Spectroscopy to reproduce the same searing conditions experienced by meteorites as they enter the Martian atmosphere. The team heated the meteorite fragments to 1000 degrees Celsius and measured the gases that were released using an infrared beam.

When quantities of gas released by the laboratory experiments were combined with published calculations of meteorite in-fall rates on Mars, the scientists calculated that only 10 kilograms of meteorite methane was produced each year, far below the 100 to 300 tonnes required to replenish methane levels in the Martian atmosphere.

More information: "Investigating the contribution of produced by ablating micrometeorites to the of Mars," journal, Richard W. Court, Mark A. Sephton

Source: Imperial College London (news : web)

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User comments : 11

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yyz
4.7 / 5 (3) Dec 08, 2009
Sounds like one (hypothesis) down, two to go. Are there only two likely contenders regarding the 'Mars methane' question? If so, that would be great.
Shootist
5 / 5 (1) Dec 08, 2009
Abiogenic ethane has been shown to be possible on Terra. Can methane be far behind? google abiogenic petroleum.
baudrunner
1 / 5 (1) Dec 08, 2009
I am not surprised. I surmised as much in an article on my blog at baudrunner dot blogspot dot com. Links in the left sidebar - "methanogens in Mars". I also expounded on perhaps the most exciting moon in the solar system - "Titan", where conditions similar to a pre-biotic Earth suggest that life may very well occur there as well when certain cyclic conditions prevail. How fantastic is that?!?

jerryd
not rated yet Dec 08, 2009

As comets have a fair amount of methane and are as common as meteorites and both the earth and Mars travel through comet trails space can be a source.

Next any time you get heat, pressure, H2 or water and C or CO2 plus iron or other catalysts underground you can easily get methane like some of the earth methane comes from.
LKD
2 / 5 (1) Dec 09, 2009
It's nice to hear that life forms are still considered a possible source, but wouldn't they need water to exist? Assuming (likely) there are large quantities of water molecules underground. So wouldn't the microscopic life forms be the least likely contender?
Velanarris
4.7 / 5 (3) Dec 09, 2009
It's nice to hear that life forms are still considered a possible source, but wouldn't they need water to exist? Assuming (likely) there are large quantities of water molecules underground. So wouldn't the microscopic life forms be the least likely contender?

In regards to water, we've found bioslimes that survive inside almost completely dried out volcanic rock. If Mars has even a hint of water below the crust, there's potential for extremophiles.
RayCherry
1 / 5 (1) Dec 09, 2009
The Rovers have captured evidence of morning mists and ground frosts ... though only very occassionally. Assuming that the Rovers are not in the best regions for such conditions, there should exist other regions where this humidity is more frequent. Even if it was a once in a few weeks, we have many examples of organisms that can survive extended periods with little or no water.

Not sure that strange bacterias and algae will be good news to the pioneers from here, but perhaps some mineral and or biological encouragement to those lifeforms could increase the greenhouse gases and lead to a more interesting atmosphere for more martian and human life in the future.
barakn
not rated yet Dec 09, 2009
Odd that they'd totally ignore yet another possible source, methane hydrates (a.k.a. methane clathrate).
http://www.mdswat...ates.pdf
http://www.astron...;id=4009
Velanarris
not rated yet Dec 09, 2009
Odd that they'd totally ignore yet another possible source, methane hydrates (a.k.a. methane clathrate).
http://www.mdswat...ates.pdf

How would you go about proving methane clathrates with no evidence of subsurface hydration? Interesting hypothesis though.
MarsArtifactResearch
1 / 5 (1) Dec 09, 2009
The dog and pony show continues. As someone who has a strong background in horticulture, and digital photography, I can state unequivocably that there are plants-- many plants-- in the MER photos. I have four videos on You-tube showing plant life, with more on the way. Stop the lying!!!!
Velanarris
4 / 5 (1) Dec 10, 2009
The dog and pony show continues. As someone who has a strong background in horticulture, and digital photography, I can state unequivocably that there are plants-- many plants-- in the MER photos. I have four videos on You-tube showing plant life, with more on the way. Stop the lying!!!!

Yep, the guys who built the base on the dark side of the moon planted them [/sarcasm]

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