What is a meteorite?

A meteorite is a piece of rock or metal from space that has fallen all the way to the ground. In this first lesson you will meet the three words that every space-rock explorer needs.

Rocks that travel through space

Space is not completely empty. As well as the Sun, the planets and their moons, our Solar System is full of smaller rocky and metal objects. The big ones, from about the size of a house up to hundreds of kilometres across, are called asteroids. Many of the tiny ones are no bigger than a grain of sand or a pebble. A small piece of rock or metal travelling through space is called a meteoroid.

Meteoroids zoom around the Sun just as Earth does. Most of them never come anywhere near us. But every now and then one crosses Earth's path, and that is when something exciting happens. Scientists usually say a meteoroid is anything from a speck of dust up to about one metre across. Anything bigger is counted as an asteroid.

Meteoroid, meteor, meteorite

These three words sound alike, but each one means something different. Here is an easy way to remember them.

A meteoroid is the rock while it is still out in space.

A meteor is the streak of light you see in the sky when a meteoroid plunges into the air around Earth. The rock is going so fast that it makes the air glow brightly. People often call meteors shooting stars, even though they have nothing to do with real stars.

A meteorite is the piece that survives the fiery journey and lands on the ground. You can only hold a meteorite, never a meteor!

So the same rock can have three names: meteoroid in space, meteor in the sky, and meteorite on the ground.

Why meteorites are special

Almost every rock you have ever touched was made here on Earth. A meteorite is different: it is a real piece of another world. Most meteorites are broken bits of asteroids. A few have come from the Moon and a few from the planet Mars.

Many meteorites are about 4.5 billion years old, which makes them older than any rock you can find on Earth's surface. They formed at the very beginning of the Solar System, around the time the planets were being built. That is why scientists love them. Studying a meteorite is a little like reading a very old letter that tells us how the Sun and planets began.

In the lessons that follow you will find out where meteorites come from, what they look like, and how people find them.

Did you know?