What is a meteorite?
Meteorites are fragments of rock and/or metal that fall to earth from space after breaking away from a larger extraterrestrial body. They measure anything from a fraction of a millimeter to the size of a football pitch and some can get bigger.
Captured by Earth’s gravitational force, they are accelerated to speeds of over seven miles per second. As they enter Earth’s thick gassy atmosphere they slow rapidly due to the friction and glow, flashing across the sky like spectacular fireworks, before finally crashing to the ground.
Where do meteorites come from?
Most meteorites are fragments that have come away as two asteroids collide. Asteroids are irregular-shaped rocks that orbit the sun. There are thousands of asteroids in our solar system, most in an orbit between Mars and Jupiter known as the asteroid belt. The asteroid belt was formed when the solar system was born about 4,568 million years ago, from a cloud of gas, dust and ice.
A small proportion of meteorites come from the moon and the planet Mars. These meteorites are much younger than those from asteroids, some as young as 2,500 million years and 180 million years old respectively.
We know where they have come from because their composition is very similar to moon rock brought back from the Apollo lunar mission and martian soil from the Viking probe.
Where are meteorites found?
Although not many meteorites are seen hitting the ground and most of them fall into the sea, thousands are found each year. Meteorites can be found all over the world, but are easiest to spot in dry places, such as deserts, where they do not erode quickly and are less likely to be obscured by different forms of vegetation.