Martian meteorite older than most
Rock landed in Sahara, is 2.1 billion years old
LOS ANGELES • Scientists are abuzz about a rock from Mars that landed in the Sahara Desert: A year-long analysis revealed it’s quite different from other Martian meteorites.
Not only is it older than most, it also contains more water. The baseball-size meteorite, estimated to be two billion years old, is strikingly similar to the volcanic rocks examined by the NASA rovers Spirit and Opportunity on the Martian surface.
“Here we have a piece of Mars that I can hold in my hands. That’s really exciting,” said Carl Agee, director of the Institute of Meteoritics and curator at the University of New Mexico who led the study published online Thursday in the journal Science.
Most space rocks that fall to Earth come from the asteroid belt, but some can be traced to the moon and Mars.
Scientists believe an asteroid or some other large object struck Mars, dislodging rocks and sending them into space. Occasionally, some plummet through Earth’s atmosphere.
Short of sending a spacecraft or astronaut to the red planet to haul back rocks, Martian meteorites are the next best thing for scientists seeking to better understand how Earth’s neighbour transformed from a tropical environment to a frigid desert.
About 65 Martian rocks have been recovered on Earth, mostly in Antarctica or the Sahara. The oldest dates back 4.5 billion years to a time when Mars was warmer and wetter. About half a dozen Martian meteorites are 1.3 billion years old, and the rest are 600 million years or younger.
The latest meteorite, known as NWA 7034 and nicknamed “Black Beauty,” was donated to the University of New Mexico by an American who bought it from a Moroccan meteorite dealer last year.
Researchers performed a battery of tests on the meteorite and, based on its chemical signature, confirmed it was blasted to Earth from Mars. At 2.1 billion years old, it’s the secondoldest known Martian meteorite.
There’s also evidence it was altered by water, which adds to evidence there were pockets of water near the surface during a time when the planet was mostly dry and dusty.