Tue, Oct 08, 2013
Even more, scientists confirm first-ever finding of a fragment of the comet's core.
Most have heard of the treasures of the 18th Dynasty pharaoh Tutankhamun, first discovered by Howard Carter and Lord Carnarvon in 1922 when they uncovered his tomb in the Valley of the Kings in Egypt. Few are familiar with his impeccably preserved brooch, recovered along with the numerous other artifacts within the tomb. Fewer still know about the striking yellow-brown scarab that is set at its center, and that it is made of a yellow silica glass stone procured from the sand of the Sahara and then shaped and polished by ancient craftsmen. The silica glass was originally formed 28 million years ago, when an ancient comet entered the earth's atmosphere and exploded over Egypt, heating up the sand beneath it to a temperature of about 2,000 degrees Celsius and resulting in the formation of a huge amount of the yellow silica glass, which lies scattered over a 6,000 square kilometer area in the Sahara.
The silica glass was one of a number of clues that eventually led Professor Jan Kramers of the University of Johannesburg, South Africa, and colleagues to a remarkable new discovery. At the center of it all is a mysterious black pebble found years ago by an Egyptian geologist in the area of the silica glass. After conducting highly sophisticated chemical analyses on this pebble, Professor Jan Kramers of the University of Johannesburg and a team of colleagues came to the inescapable conclusion that it represented the very first known hand specimen of a comet nucleus, rather than simply an unusual type of meteorite.
