Extinctions

Incredible heat was needed to turn sand in an Egypt desert into yellow-green glass. Searching for clues as to what could generate such heat, scientists first looked at the 1908 Tunguska event in Siberia; the wide-spread destruction is believed to have been caused by an exploding asteroid. Viewing the 1994 collision of a comet with Jupiter provided scientists with answers. The huge fireball that it generated was validation of their theory that an asteriod impact some 30,000 ago could easily have turned an Earth desert into glass. AKA: Ancient Asteroid Apocalypse (Sky)