Meteorites

The Chelyabinsk meteor that exploded in 2013 in the atmosphere over a remote part of Siberia, made headline news internationally when its shock wave caused much damage to buildings, and injuries to more than 1500 due to flying glass and other debris from the affected buildings. Very little of the original object has been found and large intact meteorites are relatively rare.

Te largest known meteorite on Earth, the Hoba meteorite, has an estimated mass of more than 60 tons – and can be found here in Southern Africa. It lies near Grootfontein in Namibia, and has been declared a national monument to protect it against vandalism. Yet, it is dwarfed by much larger meteorites that have struck Earth in the past. One that may have been about 10 km across, created the largest known meteor impact site in the world more than two billion years ago. We know it as the Vredefort Dome – one of our World Heritage sites.

But what are meteorites? In short, they are meteors that were large enough to survive an impact with Earth’s atmosphere. Meteors are ‘debris from space’, and contain a wealth of information about the kind of the formation of the Solar System. They can be as small as a speck of dust, and most of them burn up in the atmosphere to be seen as ‘shooting stars’ at night. But depending on the conditions – their composition, size and angle at which they enter the atmosphere and the speed at which they travel – some larger ones end up as rocks on Earth. Read more in this user-friendly book by Ronnie McKenzie. It is intended to give the non-specialist an idea of why these objects are so interesting and where to see some of them.

ISBN 978-1-77584-098-5, Struik Nature

 

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