[meteorite-list] Fiery Rock Will Test Whether life Came From Space (Foton M3)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 14 Aug 2007 11:00:24 -0700 (PDT)
Message-ID: <200708141800.LAA15624_at_zagami.jpl.nasa.gov>

http://space.newscientist.com/article/dn12469-fiery-rock-will-test-whether-life-came-from-space.html

Fiery rock will test whether life came from space
David Shiga
New Scientist
13 August 2007

A rock will be hurled into space on a rocket and subjected to the fiery
heat of re-entry into Earth's atmosphere to test whether life could have
hitched a ride from one planet to another in debris from an asteroid strike.

The rock is one of 35 experiments to fly on a European Space Agency
mission called Foton M3, which is set to launch on 14 September from the
Baikonur Cosmodrome in Kazakhstan.

Some scientists say life could have spread around the solar system by
hitching rides inside rocks blasted from one planet or moon to another
by asteroid impacts (see Earth rocks could have taken life to Titan
<http://www.newscientist.com/article/dn8867>).

Loch rock

To investigate that idea, John Parnell at the University of Aberdeen in
the UK designed the experiment, which involves a 400-million-year-old
rock formed from sediment at the bottom of an ancient lake in Scotland.

The fist-sized rock will be protected inside the spacecraft during
launch, then uncovered when the craft re-enters the atmosphere at 8
kilometres per second.

Researchers want to see how the re-entry affects molecules in the rock
that are believed to form only from the decay of living things, such as
steranes and hopanes, which in this case come from algae. "The outer
part might have melted or possibly disintegrated, but the interior
portion might be rather better preserved," Parnell told New Scientist.

Steranes and hopanes, which are derived from cell walls, are especially
promising as a possible signature of ancient life in meteorites because
they stay around for so long. "Unlike things like DNA that decompose
quite quickly, these have long-term stability over millions or even
billions of years," Parnell says.
          
Fossil biomarkers

"This experiment is really designed to look at fossil biomarkers rather
than living ones," he continues. "But the more you know about the
survival of organic molecules in general, the more you can understand
whether living [things] could survive as well."

The results will help determine whether there is hope of finding such
signatures in meteorites from Mars. In 1996, scientists said they had
found fossilised signs of ancient life in a Martian rock, though many
researchers dispute the claim (see Hunting life in Martian rocks
<http://www.newscientist.com/article/mg19125661.500>).

Jean Pierre de Vera of Heinrich Heine University in D?sseldorf, Germany,
who is not involved in the experiment, says better knowledge of the
biomarkers used in the experiment could also help scientists recognise
signs of life on Mars and elsewhere in the solar system. "This is
important for the search for recent or past life forms on other
planets," he told New Scientist.

De Vera is involved in another experiment on Foton M3 that bears on the
transfer of life by meteorites. Called STONE, it will expose a rock
colonised by lichens to the heat of re-entry to see whether the lichens
can survive.
Received on Tue 14 Aug 2007 02:00:24 PM PDT