Asteroid, meteor and meteorite differences

This is a close-up of the asteroid Eros — the first asteroid in our solar system to have a spacecraft land on it. NASA/JPL/JHUAPL

Asteroid (noun, “AS-tear-oyd”), Meteor (noun, “ME-tee-or”), Meteorite (noun, “ME-tee-or-ite”)

These are three words for the same object in different places. They all describe a rocky body from space. An asteroid is a small rocky object that orbits the sun. Asteroids are smaller than a planet. They don’t form spheres and aren’t big enough to keep other objects out of their way. But asteroids are large enough to hit each other. Some asteroids break off smaller chunks when they collide. Those small chunks are called meteoroids. Those also orbit the sun.

The orbits of some asteroids and meteoroids bring these objects close to Earth. If one gets close, it might get grabbed by Earth’s gravity and fall through the atmosphere. When it does, it becomes a meteor. Meteors are vaporizing asteroids or meteoroids. They are heating up so much that their rock turns to vapor as they fall. They are so hot they are incandescent — meaning they emit light. We see them as streaks of light in the sky.

Most of the time, meteors vaporize completely. But every once in a while, the remains hit the ground. Then, the object becomes a meteorite. Meteorites haven’t changed a lot since they were formed early in the history of the solar system. They are very similar to the rocks that may have formed our planet billions of years ago. Scientists study meteorites to understand how the Earth may have formed.