What Are Meteorites?

Plenty of romantics have made a wish on a shooting star as it streaks across the night sky. Those brilliant beacons of hope are actually pieces of space debris burning up in Earth's atmosphere. And if a part of them makes it to the ground, it gets a new name.A meteorite is the term given to a piece of a comet or asteroid that falls into the Earth’s atmosphere and survives to hit the surface. These objects come in three easy-to-remember categories: stony, metallic and stony metallic.

Stony meteorites, as the name implies, are made from rocky material not all that different from what's found in the ground on our planet. These objects are the most common type of meteorites and are thought to represent leftover fragments from the creation of our solar system. Such meteorites often contain organic, or carbon-containing, compounds, the molecular basis of living organisms, and sometimes even traces of water, suggesting that the ingredients for life may have originated before our world was born.

Metallic meteorites contain mostly iron and nickel, while stony-metallic meteorites are made from both rocky and metallic material. Only around 8 percent of meteorites fall into either of these categories, according to "Meteorites and the Early Solar System II," a book from the Lunar and Planetary Institute in Houston. Some of these meteorites originated on the moon or Mars and have therefore given scientists insights into different bodies in the solar system.

Among the most famous fallen space rocks is the Murchison meteorite, which fell to Earth in 1969 and has since been well-studied because it is rich in organic compounds.

And the Hoba meteorite is the largest known meteorite. It weighs 60 tons (54 metric tons) and was found on a farm in Namibia. It's so big that it's never been moved and is now part of a tourist attraction.