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Tripoli, 10 October 2013:
An unusual black stone found in the Libyan desert proves that a comet hit Earth millions of years ago and could help reveal how the solar system was formed, according to scientists at a South African university.
Sophisticated chemical analysis of the stone, described as a “mysterious black pebble,” led the team, from Johannesburg’s University of Wintersrand, to conclude that it represented the first known specimen of a comet nucleus. Professor Jan Kramers said that the “euphoric” realisation came only when the team had eliminated all other possibilities.
“Comets always visit our skies – they are these dirty snowballs of ice mixed with dust – but never before in history has material from a comet ever been found on Earth,” said Professor David Block.
The stone, which was found some years ago by an Egyptian geologist, apparently contains lots of tiny diamonds, believed to have been formed by the impact of the comet hitting Earth. It has been named Hypatia, after the female mathematician, astronomer and philosopher, Hypatia of Alexandria.
The comet entered Earth’s atmosphere over the Sahara Desert some 28 million years ago, the scientists said. It exploded when it entered the atmosphere, heating the sand to temperatures of 2,000 degrees Celsius, resulting in the formation of a large amount of yellow-coloured silica glass – Libyan desert glass – which can still be found scattered over a 6,000 square-kilometre area of the desert, spanning the Libyan-Egyptian border. It was in this area that the Hypatia stone was discovered.
Block, Kramers and Dr Marco Andreoli are presenting their research in a public lecture this evening at University of Witwatersrand.
Their findings have also been published in the science journal Earth and Planetary Science Letters. An online version of the article can be found here:
http://www.sciencedirect.com/science/article/pii/S0012821X13004998 [/restrict]
