First Evidence That Comet Hit Earth 29 Million Years Ago Revealed

It might not look like much, but scientists in South Africa are calling a little black pebble the first evidence that a comet hit the Earth millions of years ago.

Found several years ago in southwestern Egypt, the mysterious rock was initially believed to be just another meteorite. But new research by the team of scientists shows that the carbon-rich specimen is actually a piece of the nucleus, or core, of a comet that hit the Sahara Desert about 28.5 million years ago.

"It’s a typical scientific euphoria when you eliminate all other options and come to the realization of what it must be," the University of Johannesburg's Jan Kramers said in a written statement.

The scientists theorize that the comet in question exploded as it entered Earth's atmosphere way back when, decimating life in its path and melting grains of sand on the ground into yellowish glass (commonly called Libyan desert glass). It was among fragments of this glass that the pebble -- now dubbed "Hypatia" by researchers -- was found.

The team will present their findings Thursday at the University of the Witwatersrand in Johannesburg. The research is also scheduled to be published in the journal "Earth and Planetary Science Letters" in November.