Impact Craters on Earth

Compared with other planets, impact craters are rare surface features on Earth. There are two main reasons for the low number of craters. One is that our atmosphere burns up most meteoroids before they reach the surface. The other reason is that Earth's surface is continually active and erases the marks of craters over time. The picture is the Barringer Meteorite Crater found in Arizona. It was probably formed about 50, 000 years ago when an iron meteorite struck the Earth's surface. Many other large craters are found in Australia, Canada and Africa.