For art collectors, the latest must-have objects are, quite literally, falling from the sky.

Boldface names like Steven Spielberg and Yo-Yo Ma are buying meteorites from auction houses at prices that are out of this world.

On Oct. 28 in New York, Bonhams auctioneers will hold their first-ever sale devoted exclusively to meteorites, and prices are expected to climb well past the seven-figure mark.

"The natural world is making a foray into the art world," explains Barbara Tapp, editor of Art & Antiques.

The jewel of the Bonhams sale is a $1.3 million chunk of the American Museum of Natural History's Willamette meteorite, the largest one ever found in the United States. But despite the frisson, some scientists fret.

Denton Abel, curator of the museum's meteorite collection, sums up their worries: "When stuff from nature is less trendy, these things could be discarded without thought."