Natural History Museum, London
A piece of the Tissint meteorite, which fell to Earth in Morocco last year.
By SINDYA N. BHANOO
A meteorite that landed in the Moroccan desert last summer was ejected from the surface of Mars 700,000 years ago, a new study reports. The meteorite is composed of an abundance of black glass, with noble gases trapped inside.
Mark Mauthner/Heritage Auctions
On this piece of the Tissint meteorite, black glass is visible on the upper right.
“Based on the noble gas measurements, we could calculate the ejection
age of the meteorite,” said Hasnaa Chennaoui Aoudjehane, an astronomer
at the Hassan II University in Casablanca, Morocco, and the study’s first author.
The study appears in the current issue of the journal Science.
The meteorite, called Tissint
after a nearby village, is only the fifth Martian meteorite that people
have witnessed falling to Earth. There are about 60 known meteorites
thought to be from Mars.
But Tissint is unique because it fell into the desert and suffered
little damage from Earth’s environment. “We had no rain between the
moment it fell and the moment it was collected,” Dr. Aoudjehane said.
“It was fresh, and it is very exciting to be able to analyze this.”
By analyzing the noble gases trapped in the glass, along with its oxygen
isotopes and minerals, she and her colleagues were able to determine
that the rock is Martian.
The meteorite may have been knocked loose from Mars by an asteroid or
some other large body that hit the planet, the researchers believe. The
impact may have also caused some melting, creating the black glass and
preserving a Mars “signature” inside the glass.
Pieces of the meteorite are on display at several museums, including the Museum of Natural History of Vienna and the Natural History Museum in London.
http://www.nytimes.com
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