What is the term for a space rock that enters Earth's atmosphere and hits the ground? Meteor, meteoroid, meteorite, or meteoroid? Meteoroids become meteors when they enter our atmosphere and meteorites when they hit the ground.
Just like meteoroids are relatively small rocks that are zipping around in space, asteroids are bigger ones and two of those have been in the news recently. The first one passed very close by Earth on August 16th. It was about the size of a car and scientists say it probably wouldn't have hurt anyone if it had entered our atmosphere. But NASA missed it. The agency didn't pick up on the asteroid until after it had whizzed by less than 2,000 miles away. And researchers say that makes it the closest asteroid ever known to pass by Earth and not hit it.

NASA didn't miss another asteroid that's headed our way. This one's about six and a half feet in diameter and should zip by on November 2nd. Scientists say the chance of this rock hitting Earth is about 4/10 of 1%. They don't expect it to have a major impact or to disrupt the U.S. election the next day.
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