Comets are balls of ice and dust. They orbit the sun. When it gets close to the sun it melts and gas and dust form a Tail that stretches millions of miles. They also reflect light and form a bright Head. solid gas spreads out in a cloud and forms a Coma. It has an icy core called a Neucles. It is covered in dust and made of frozen water, gas, rocks, and metal. Comets can go 150,000 miles per hour. No comet goes faster than 1,476,000. In 1994, comet Shoemaker-Levy 9 broke into pieces and smashed into Jupiter.
There are millions of asteroids. Most of them are in the Asteroid Belt between Mars and Jupiter. But there are smaller groups in different orbits. Just over 5,000 of them are named. Asteroids come in many sizes. The bigest is named Ceres it is 580 miles across.
When they are in space there called Meteoroids, when they are in the atmosphere they are meteors, and when they are on earth they are meteorites. The Meteor Crater in Arizona is 560 feet deep and was created by a meteorite 150 feet wide. The heaviest surviving meterorite is 60 tons in Tloba West, Namia Africa. In 1993 in N.Y. a meteorite smashed a car.
