The day it rained glass: Tektites: amazing pebbles with great impact

摘要

A THEORY about one of earth's most catastrophic impact events has ended decades of speculation over the origin of Australia's tektites — naturally occurring pebble-sized glass objects. It seems as if they all fell from the sky one day when it literally rained glass. About 770,000 years ago, as herds of lumbering, rhinoceros-sized diprotodon fed on plants and mobs of giant square-faced kangaroos made their way across the outback, a chunk of rock the size of a small town collided with the earth at a very low angle some 4000 km to Australia's north. "The exact location of the impact site is still to this day unknown, but the Cambodia and Laos area is the likely location," says Associate Professor Alex Bevan, the curator of minerals and meteorites at the WA Museum.