Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: royden on 10/09/2009 10:30:03
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Royden Edward Hodgskin asked the Naked Scientists:
How come there is no impact crater around the huge meteorite that's lying in the Namibian desert? Surely one this size would have caused untold devastation?
What do you think?
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From:
http://en.wikipedia.org/wiki/Hoba_meteorite (http://en.wikipedia.org/wiki/Hoba_meteorite)
It is inferred that the Earth's atmosphere slowed the object down to the point that it fell to the surface at terminal velocity, thereby remaining intact and causing little excavation. The meteorite is unusual in that it is flat on both major surfaces, possibly causing it to have skipped across the top of the atmosphere in the way a flat stone skips on water.
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I visited that site a few years ago. The thing is a big rectilinear chunk of iron, the same shape that might be most easily produced in a foundry. It is lying nice and flat just below the surface level. Very convenient. If you were pulling something that heavy, it would be easier to dump it in that orientation that any other. Meteorites, on the other hand, tend to be rather irregular. The little indentations on the surface are a nice touch. It would be interesting to see if the same pattern continues on the bottom surface. Maybe it dropped off an alien space barge.
Well, it may not have been a deliberate hoax, but I'd bet a buck it isn't a meteorite.
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Well, it may not have been a deliberate hoax, but I'd bet a buck it isn't a meteorite.
If it is a hoax it's an elaborate one : they saw fit to include a large percentage of Nickel, just like a real meteorite...
Ni[ckel] is always present, the concentration lies between 5 and about 25%. It can be used to distinguish meteoritic irons from technical products, which contain usually lower amounts of Ni.
http://en.wikipedia.org/wiki/Iron_meteorite#Composition