Antarctic craters reveal asteroid strike

[emad]

Paul Brown
Thursday August 19, 2004
The Guardian

Snip:
Scientists using satellites have mapped huge craters under the Antarctic ice sheet caused by an asteroid as big as the one believed to have wiped out the dinosaurs 65m years ago.

Professor Frans van der Hoeven, from Delft University in the Netherlands, told the conference that the evidence showed that an asteroid measuring between three and seven miles across had broken up in the atmosphere and five large pieces had hit the Earth, creating multiple craters over an area measuring 1,300 by 2,400 miles.

The effect would have been to melt all the ice in the path of the pieces, as well as the crust underneath. The biggest single strike caused a hole in the ice sheet roughly 200 by 200 miles, which would have melted about 1% of the ice sheet, raising water levels worldwide by 60cm (2ft).

But the climatic conditions were different at the time of the strike - about 780,000 years ago - from when the asteroid that is believed to have wiped out the dinosaurs struck Yucatan in Mexico. That impact created dust storms and fires that, by blocking out the sun, cooled the Earth's atmosphere so much that the dinosaurs could not survive. The Antarctica strike occurred during an ice age, so even tidal waves would have been weakened to mere ripples by the calming effect of icebergs on the ocean.
More:
http://www.guardian.co.uk/space/article/0,14493,1286033,00.html

[Frodo]

1. Cool!