LOS ANGELES -- Scientists are abuzz about a coal-coloured 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 as meteorites come from the asteroid belt, but a number 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.
Researchers performed a battery of tests on the meteorite -- nicknamed "Black Beauty" -- and based on its chemical signature confirmed it was blasted to Earth from Mars. More tests are underway to determine how long the rock floated in space and how long it had been sitting in the Sahara.
-- The Associated Press