Stony Apophis

Near-Earth asteroid Apophis is a stony chondrite, researchers say. That means it's a solid body, not a pile of rocks loosely held together by gravity, as some asteroids are.

Knowing that is important for two reasons. First, Apophis may be a candidate for an early human mission to an asteroid, perhaps late next decade. Second, it might pose a threat to Earth. By current calculations, in 2028 Apophis will pass within 22,000 miles of Earth-- about a tenth of the Moon's distance-- and in 2036 there's a 1-in-45,000 chance that it will hit Earth.

Technologies and techniques to allow us to deflect bodies away from Earth are being developed. The first step is to understand the structure and composition of the body in question. That first step is currently in stride at Apophis.