Asteroid vs. Meteor

Asteroids and meteors are closely related because they are both names for the same object, but differ based on the location of the object.

An asteroid is a small, rocky body that orbits the Sun, generally in the 'asteroid belt' between Mars and Jupiter. They can be almost as large as a planet or as small as a few meters wide. Asteroids normally orbit the Sun, but can enter the Earth's atmosphere, at which point they are called meteors.

A meteor is a small, rocky body that has entered Earth's atmosphere from outer space. Most meteors burn and glow brightly as they fall swiftly through the Earth's atmosphere. Many meteors burn out completely before reaching the ground. They are generally composed of rock and metallic elements.

The only difference between asteroids and meteors (and meteorites) is their location. All meteors start off as asteroids (in outer space). Once they enter the Earth's atmosphere, they are called meteors, and once they hit the ground they are called meteorites. Scientists can learn a lot about outer space by studying meteorites.