[meteorite-list] New Mars Meteorite Fell in Morocco Last July (Tissint Meteorite)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 17 Jan 2012 12:20:49 -0800 (PST)
Message-ID: <201201172020.q0HKKneY024249_at_zagami.jpl.nasa.gov>

http://www.time.com/time/health/article/0,8599,2104649,00.html

Mars Rocks Fell in Africa Last July
By Seth Borenstein (Associated Press)
January 17, 2012

(WASHINGTON) - Scientists are confirming a recent and rare invasion from
Mars: meteorite chunks from the red planet that fell in Morocco last July.

This is only the fifth time scientists have confirmed chemically Martian
meteorites that people witnessed as they fell. The fireball was spotted
in the sky six months ago, but the rocks were not discovered on the
ground in North Africa until the end of December.

This is an important and unique opportunity for scientists trying to
learn about Mars' potential for life. So far, no NASA or Russian
spacecraft has returned bits of Mars, so the only Martian samples
scientists can examine are those that come here in meteorite showers.

Scientists and collectors of meteorites are ecstatic, and already the
rocks are fetching big money because they are among the rarest things on
Earth, rarer even than gold.

A special committee of meteorite experts, including some NASA
scientists, confirmed the test results Tuesday. They certified that 15
pounds (7 kilograms) of meteorite recently collected came from Mars. The
biggest rock weighs more than 2 pounds (1 kilogram).

Astronomers think millions of years ago something big smashed into Mars
and sent rocks hurtling through the solar system. After a long journey
through space, one of those rocks plunged through Earth's atmosphere,
splitting into smaller pieces.

Most other Martian meteorite samples sat around on Earth for millions of
years, or at the very least for decades, before they were discovered,
which makes them tainted with Earth materials and life. These new rocks,
while still probably contaminated because they have been on Earth for
months, are purer.

The last time a Martian meteorite fell and was found fresh was in 1962.
All the known Martian rocks on Earth add up to less than 240 pounds (110
kilograms).

The new samples were scooped up by dealers from those who found them.
Even before the official certification, scientists at NASA, museums and
universities scrambled to buy or trade these meteorites.

"It's a free sample from Mars. That's what these are, except you have to
pay the dealers for it," said University of Alberta meteorite expert
Chris Herd, who heads the committee that certified the discovery.

He already has bought a chunk of meteorite and said he was thrilled just
to hold it, calling the rock "really spectacular."

One of the crucial decisions the scientists made Tuesday was to connect
these rocks officially to the fiery plunge witnessed by people and
captured on video last summer. The announcement and the naming of these
meteorites - called Tissint - came from the International Society for
Meteoritics and Planetary Science, which is the official group of 950
scientists that confirms and names meteorites.

Meteorite dealer Darryl Pitt, who sold a chunk to Herd, said he charges
$11,000 to $22,500 an ounce and has sold most of his supply already. At
that price, the new Martian rock costs about 10 times more than gold.

"It's scientifically invaluable," Herd said. "These are really beautiful
specimens. It's a rare type, so fresh and aesthetically pleasing."

Several of the world's top experts in meteorites, including those who
work for NASA, told The Associated Press that they were sure this was a
piece of Mars. Tony Irving of the University of Washington is the
scientist who did the scientific analysis on the rocks and said there is
no doubt that they are from the red planet.

Scientists can tell when meteorites are from Mars because they know what
the Martian atmosphere is made of, thanks to numerous probes sent there.
The chemical signature of the rocks and the Martian air match, Irving
said. Another clue is that because planets like Mars are more
geologically active, its rocks tend to be much younger - millions of
years old instead of hundreds of millions or more - than those from the
moon or asteroids.

Most of the Martian rocks on Earth have been around for centuries or
longer and have been found in Antarctica or the desert. They look so
similar to dark Earth rocks that if they fell in other places, such as
Maryland, they would blend right in and never be discovered, Irving said.

Jeff Grossman, a NASA scientist who is the Meteoritical Society's
database editor, said there is a higher probability of finding
"something interesting" from Mars on these rocks because they fell so
recently. However, six months is a long time for Earthly contamination
to take root, he said.

Herd said the first thing he would do with the rocks would be to rinse
them with solvents to try to get rid of earthly contamination and see
what carbon-based compounds are left.

A Martian meteorite that was buried in Antarctica made news in 1996.
NASA scientists theorized that the rock, found in 1984, showed signs of
traces of life from Mars, fossils of what seemed to be lifelong forms.
Even the White House made an announcement about it as the first sign of
life outside of Earth. Years of study since then have led much of the
astronomy world to conclude that there was not enough evidence to
support the claim.

Because known Martian meteorite falls happen only once every 50 years or
so - 1815 in France, 1865 in India, 1911 in Egypt and 1962 in Nigeria -
this is a once-in-a-career or even one-in-a-lifetime event.

"It's incredibly fresh. It's highly valuable for that reason," said Carl
Agee, director of the Institute of Meteoritics and curator at the
University of New Mexico. "For someone who knows their Martian, this is
a beauty. It's gorgeous."
Received on Tue 17 Jan 2012 03:20:49 PM PST