Killer Asteroid Count

NASA's WISE spacecraft, which uses the infrared part of the spectrum to gather data not available to visible light, has found 93 percent of the near-Earth asteroids that are one kilometer in diameter or larger. Those are the rocks that could potentially end all life on Earth in a collision. WISE has also found far fewer rocks 100 meters in diameter and up than expected.

All that is good news, but keeping track of all these objects will still be necessary-- and there's still that last 7 percent of the really big boys to find.