[meteorite-list] Life on Mars theory boosted by new methane study

From: Michael Groetz <mpg4444_at_meteoritecentral.com>
Date: Wed, 9 Dec 2009 08:30:49 -0500
Message-ID: <ad733150912090530n3f406b72mb65511e269b82644_at_mail.gmail.com>

http://www.physorg.com/news179499648.html

Life on Mars theory boosted by new methane study

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 Mars
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 Martian soil 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 volcanic rock 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.
Received on Wed 09 Dec 2009 08:30:49 AM PST