LOS ANGELES (AP) — Scientists are abuzz about a rock from Mars that landed in the Sahara desert: A yearlong 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 2 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.