[meteorite-list] Researchers Dispute Life-On-Mars Report

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:47:13 2004
Message-ID: <200111201846.KAA13914_at_zagami.jpl.nasa.gov>

http://www.chron.com/cs/CDA/story.hts/nation/1138620

Researchers dispute life-on-Mars report

Meteorite evidence inadequate, they say

By PAUL RECER
Associated Press
November 19, 2001

WASHINGTON -- A group of researchers say NASA scientists have failed to
prove their contention that a Mars meteorite contains evidence of ancient
microbial life on the Red Planet.

A group led by Peter R. Buseck of Arizona State University said that the
NASA researchers have inadequate evidence showing that tiny crystalline
structures in Mars meteorite ALH84001 were formed by bacteria billions of
years ago as the rock was sitting on the Martian surface.

A study with Buseck as the first author appears today in the Proceedings of
the National Academy of Sciences.

Buseck said that NASA-supported researchers claimed in February that
crystals found in the meteorite are identical to crystals formed on Earth by
bacteria.

The material, known as magnetite, is formed by some bacteria that live on
the bottom of lakes.

The magnetic crystals act as a sort of compass to allow the bacteria to
orient themselves as they move along the lake bottom.

Buseck said there was inadequate similarity between Earthly magnetite and
that found in the Mars meteorite to prove that the material was formed by a
living organism.

"We find that there is much more uncertainty than they seem to believe,"
said Buseck, referring to the NASA researchers.

The Arizona State researcher said there are computer-driven electron
microscope techniques that can be used to determine if the NASA researchers
are correct. He said he plans to do such a study.

Everett Gibson, a NASA researcher who was among the group that first
proposed that ALH840001 contained evidence of life, said that Buseck has not
even looked at the Mars meteorite.

"How can he draw this conclusion without seeing the material?" Gibson asked.

Gibson said that other researchers have found evidence that supports the
NASA group.

In 1996, Gibson and some other NASA-supported researchers announced that
they had found evidence in ALH84001 of life -- microscopic fossils that
could have been bacteria, and carbon chemicals that are linked to life
processes.

They suggested that the bacteria lived on the Red Planet billions of years
ago, when Mars had water and warmer temperatures, and that microbes left
evidence inside the Mars rock.

ALH84001 is thought to have formed on Mars about 4.6 billion years ago and
is the oldest of 16 meteorites found on Earth that have been identified
chemically as coming from Mars.

Scientists believe that an asteroid smashed into Mars 13 million to 16
million years ago and catapulted into orbit a chunk of Mars that contained
ALH84001.

The Mars rock wandered in space for millions of years and finally fell to
Earth about 13,000 years ago. It was found in Antarctica in 1984.

Gibson said that other scientists have found evidence that supports the
findings of his team.

"Our group feels more strongly about our hypothesis now than we did in
1996," he said.
Received on Tue 20 Nov 2001 01:46:56 PM PST