MOUNTAIN VIEW -- NASA scientists at Ames Research Center in Mountain View say scientists did something Monday night that they've never been able to do before. They were able to predict where and when an asteroid would enter the earth's atmosphere.

The asteroid was about the size of a car and entered the atmosphere over the African country of Sudan going about eight miles a second.

So far there are no reports of damage. It is believed that the space rock burned up before reaching the ground, although small pieces could have made it to the ground.

Scientists said space rocks of that size usually enter the earth's atmosphere about once or twice a year.

But this time, they were able to predict the impact 12 hours in advance. David Morrison, of the NASA Lunar Science Institute, said "Our Spaceguard telescopes, the telescopes looking up and doing a catalog of asteroids happened by good luck to see this just one night before it hit."

Morrison added that the Spaceguard Project began ten years ago, but until now had never been able to forecast an asteroid collision. "The earth orbits the sun in a kind of celestial shooting gallery and we are certainly hit by all size objects. If you think about the surface of the moon, all those craters, the earth would be just as heavily cratered."

An asteroid collision with earth has been a subject of science fiction for many years. In reality, it's happened in the past and will likely happen again in the future. "If it's big enough to get through the atmosphere, it hardly slows down. It hits the ground 3 or 4 seconds after it enters the atmosphere, and there's just an explosion. It's like a big bomb going off," said Morrison.

In Arizona, there is a meteor crater measuring about one mile across. Scientists say that was made by an asteroid the size of a ten story building some 50,000 years ago.

Some people believe the dinosaurs disappeared 65 million years ago because a space rock ten miles across smashed into the earth.

The impending arrival of an asteroid doesn't bother some people, but others are concerned. Blair Hardee of Mountain View said, "It worries me because if a small asteroid like that can come into the atmosphere then a bigger one definitely could too." Al Lewis also of Mountain View countered, "That's something I really can't worry about so I try to worry about the things I can do something about."

NASA's David Morrison sees a practical application. "If you predicted the impact with just a few days or weeks warning, you could at least evacuate. If you have decades of warning then we have the space technology to go out with a space craft and actually deflect it, so it misses the Earth a little bit."

Scientists say it is just a matter of time.