Meteorites found in Calif. along path of fireball

Wasson suspected hundreds of dealers and collectors already have joined the search. He said it was important to recover the meteorites soon because any rain will cause them to degrade, losing their sodium and potassium.

"From my viewpoint as a meteorite researcher," he said, "I'm hopeful some big pieces are found right away."

Yeomens confirmed this type of meteorite is one of the oldest, dating to the origin of the solar system 4 to 5 billion years ago. And it's "actually kind of unusual," he said.

Yeomens said it's got two of the most important chemicals that scientists look for: carbon and a form of water. In fact, this type of space rock is likely full of water and would have made a good candidate for the new space company announced Tuesday that plans to mine asteroids, he said.

"And this one landed in their backyard for a lot less than they planned to spend," he said.

The mini-van sized asteroid wasn't on NASA's lengthy list of near Earth objects that they track coming close to the planet, so it took scientists by surprise. "There are millions of objects of that size that we don't know about," he said. "They're too small to image unless they're right up on top of you."

AP Science Writer Seth Borenstein contributed to this story from Washington, D.C.