[meteorite-list] Non-biological Organic Carbon Found to Originate on Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 24 May 2012 11:26:48 -0700 (PDT)
Message-ID: <201205241826.q4OIQmcu014942_at_zagami.jpl.nasa.gov>

NEWS RELEASE FROM THE PLANETARY SCIENCE INSTITUTE

FROM:
Alan Fischer
Public Information Officer
Planetary Science Institute
520-382-0411
520-622-6300
fischer at psi.edu

Non-biological Organic Carbon Found to Originate on Mars

Tucson, Arizona, May 24, 2012 - Molecules containing carbon and hydrogen -
the building blocks of all life on Earth - have been the targets of missions
to Mars from Viking to the present day. While these molecules have previously
been noticed in meteorites from Mars, scientists have disagreed about how
this organic carbon was formed and whether or not it came from Mars.

Theories about their origin include contamination from Earth or other meteorites,
the results of chemical reactions on Mars, or that they are the remnants of
ancient Martian biological life.

A new paper published May 24 in Science Express by Carnegie's Andrew Steele and
a consortium of scientists that includes Planetary Science Institute's Marc Fries
provides strong evidence that this carbon did, indeed, originate on Mars,
although it is not of biological origin. These findings give researchers insight
into the chemical processes taking place on Mars and will help aid future quests
for evidence of ancient or modern Martian life

Steele's team examined samples from 11 Martian meteorites whose ages span about
4.2 billion years of Martian history. They detected large carbon compounds in 10
of them. The molecules were found inside of grains of crystallized minerals.
Since these molecules were found in Martian meteorites of such an extraordinary
span of ages, their presence means that Mars has been making its own organic
compounds throughout its history and apparently continues to do so today.

"We knew these organic compounds were in the Martian meteorites, but until we
performed this study no one knew exactly where they were in the rocks or how
they were formed," said Fries, a research scientist at the Planetary Science
Institute. "It was a puzzle, and now we finally have enough pieces in place to
say, okay, now we understand what is going on here."

Using an array of sophisticated research techniques, the team was able to show
that at least some of the macromolecules of carbon were indigenous to the
meteorites themselves and not contamination from Earth.

"What this all means is that Mars is making its own organic compounds. Previous
to this, we thought that carbon compounds on Mars only fell there in meteorites,
or perhaps were bound up in any life forms that might be living there. Now we
know that simply finding organic compounds that aren't from meteorites doesn't
automatically mean that they come from life," Fries said. "While it sounds
like it complicates things, it actually gives us a clearer picture of Mars and
will help us build robust conclusions about whether anything is, or has been,
alive there."

In a separate paper going to press in American Mineralogist, Steele and his
team studied a meteorite called Allan Hills 84001 that was reported to contain
relicts of ancient biological life on Mars. The paper demonstrated that these
supposed remnants could have been created by chemical reactions involving the
graphite form of carbon, rather than biological processes. Both of these papers
reveal a pool of reduced carbon on Mars and will help scientist involved in
future Mars missions distinguish these non-biologically formed molecules from
potential life.

The research for the Science Express paper was funded by NASA Astrobiology, Mars
and Cosmochemistry programs, the W.M. Keck Foundation, the Natural Science and
Engineering Research Council of Canada, and the Carnegie Institution for Science.
The research for the American Mineralogist paper was supported by NASA
Astrobiology, Mars and Cosmochemistry programs.


CONTACT:
Marc Fries
Research Scientist
fries at psi.edu
619-789-7981
  
PSI INFORMATION:
Mark V. Sykes
Director
520-622-6300
sykes at psi.edu
Received on Thu 24 May 2012 02:26:48 PM PDT