An Iron Meteorite

11 Sep 2010

At ... in 1920 a farmer's plough struck a lump of metal in a field near Grootfontein in Namibia. It was an iron meteorite estimated to be 66 tons in weight - and is still where it was found. It was once much larger on the basis of the abundance of iron oxide in the surrounding soil which is thought to imply the object has suffered oxidation since it fell out of the sky some 80,000 years ago. It is composed of 84 per cent iron and 16 per cent nickel but the most surprising thing is that there was no crater. Objects such as this should theoretically punch through the atmosphere at great speed and hit the earth with great force - but this example did not do that. At it is suggested they are slowed down by electricity in order to gve them a soft landing as apparently meteorites are quite often not associated with the excavation of holes in the ground. They are often found on the surface - which begs the question, what causes cratering?