Meteorite slice, c 4500 BC.
© Science Museum / Science & Society Picture Library
This is a section from a portion of a sizeable meteorite found at Henbury, Northern Territory, Australia. The slice has been cut, ground, polished and etched to allow the internal structure to be examined. 4700 years ago, a meteor weighing several tons struck the region at some 40,000 mph, disentegrating before impact and forming twelve impact craters and scattering fragments over a wide area. The fragments are heavy, as they consist of 90 % iron and 8 % nickel. The largest piece of the meteor found weighed over 100 kg. Meteorites are fragments left over from the violent formation of the solar system, which orbit the sun and occasionally impact upon the surface of the Earth or other planets. They typically have a high metallic content.