The chairman of this week's Planetary Defense Conference, William Ailor of the Aerospace Corp., a nonprofit established by Congress to support the Air Force's space defense program, said scientists generally agree that the risk to Earth from large asteroids is small. Researchers have identified more than 700 of these potential "planet killers" -- out of an estimated 1,000 -- and found that not one is on a collision course with Earth.

"But with the smaller ones, the asteroids in the [150-yard] range, we're finding more and more," Ailor said yesterday. "They're hard to detect, and it's hard to predict where they are headed, but they can do a great deal of damage." NASA estimates that there are as many as 100,000 of the smaller asteroids in near-Earth orbit and that about 20 are "potentially hazardous."

I knew we'd get creative with the 1000 ch limit Well done.