Asteroids

Return to Astronomy Index Page

Asteroids are minor planets that lie between Mars and Jupiter. Some asteroids do orbit outside of Jupiter and Mars.

Asteroids are called minor planets. Asteroids are believed to the remains of a planetoid that use to exist between Mars and Jupiter and was destroyed by the tidal pulls of gravity in the early solar system.

Asteroids range in size from 1 kilometer  to 100's of kilometers in size.

Asteroids are made up of various materials from metal ores to rock, carbon material and ice.

Asteroids do not have atmospheres.

There are a few asteroids that have moons and some asteroids are double asteroids in that they orbit each other.

NASA presently tracks about 1,000 asteroids that can pose a threat to life on Earth, through project LONEOS.

Asteroids have impacted the Earth at least twice in Geologic History with extinction of 98% of all life around 225 million years ago and 85% extinction of all life around 65 million years ago.

Asteroid Photo Courtesy of NASA JPL