Total destruction not imminent

It seems that Earth is not at risk for getting destroyed by any large objects from space any time soon.

'Planet Killer' Not in the Stars, Asteroid Research Indicates (Washington Post)

The key paragraph related to this:

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."

US politicians are calling for NASA to come up with a program for protecting the Earth against these smaller objects.