A beautiful scarab in one of King Tut's necklaces tests to be glass. The problem is it tests far older than any of Egyptian civilization itself. Scientists now think the glass may have extraterrestrial origins:
An Austrian astrochemist Christian Koeberl had established that the glass had been formed at a temperature so hot that there could be only one known cause: a meteorite impacting with Earth. And yet there were no signs of an impact crater, even in satellite images.
American geophysicist John Wasson is another scientist interested in the origins of the glass. He suggested a solution that came directly from the forests of Siberia.
"When the thought came to me that it required a hot sky, I thought immediately of the Tunguska event," he tells Horizon.
In 1908, a massive explosion flattened 80 million trees in Tunguska, Siberia.
Although there was no sign of a meteorite impact, scientists now think an extraterrestrial object of some kind must have exploded above Tunguska. Wasson wondered if a similar aerial burst could have produced enough heat to turn the ground to glass in the Egyptian desert.