Meteorite: Properties, Facts and Photos
What is a Meteorite?
A meteorite is a piece of rock or metal from space that passes through Earth’s atmosphere and reaches the ground without being destroyed. Meteorites provide valuable information about the early solar system and the materials from which planets formed.
While still in space, the object is called a meteoroid, but once it enters Earth's atmosphere, resistance to air causes it to heat up and emit light, forming a fireball. It then becomes known as a meteor or shooting star.
Most meteorites are fragments that have come away as two asteroids collide. They can measure anything from a fraction of a millimetre to several metres across.
Asteroids are irregularly shaped rocks that orbit the sun. There are many thousands in our solar system.
Captured by Earth's gravitational force, meteorites accelerate to speeds of over 11.2 kilometres per second. As they enter Earth's thick, gassy atmosphere, they slow down rapidly because of friction. As that happens, they begin to glow. The flashes across the sky eventually crash to the ground.
Most meteorites disintegrate as they enter Earth's atmosphere; however, thousands are still found around the world each year. It's extremely rare to see one hit the ground because most seem to fall into the sea.
The best places to spot a meteorite are in dry locations, such as deserts, where they don't erode so quickly and are less likely to be obscured by vegetation.
A small number of asteroids come from the moon and Mars. Some can be as young as 180 million years old.
Particles from one of the most studied meteorites that fell in Australia in 1969 are estimated to be seven billion years old. The age of Earth is a mere 4.54 billion years old.
Meteorites are occasionally used as gemstones because of their rarity.
The iron-nickel meteorite in our photograph is housed in the Smithsonian National Museum of Natural History, Washington, D.C. Photo: Courtesy of Chuck Sutherland.
