JOHANNESBURG — South African scientists will this week present evidence of a comet that struck Earth, heating the sands of the Sahara desert to 2,000 degrees Celsius (3,632 degrees Fahrenheit) and forming the silica glass found in Egyptian King Tutankhamun’s scarab broach.

“Evidence of a comet entering Earth’s atmosphere and exploding, raining down a shock wave of fire, which obliterated every life form in its path,” Johannesburg’s University of the Witwatersrand said in an emailed statement Tuesday. “The comet entered Earth’s atmosphere above Egypt 28 million years ago.”

In addition to glass, the impact produced microscopic diamonds. Evidence of this is contained in a black, diamond- bearing pebble found “years earlier” by an Egyptian geologist, the university said.

“The authors came to the inescapable conclusion that it represented the very first known hand specimen of a comet nucleus,” the university said.

The pebble has been named Hypatia after a female mathematician and astronomer from Alexandria in Egypt.

A comet is a body made of dust, rocks and ice that orbit suns such as the one in Earth’s solar system.

The research will be presented at a public lecture at the university of the Witwatersrand, known as Wits, on Oct. 10 and will be published in Earth and Planetary Science Letters.

Charles Block of Wits, Jan Kramers of the University of Johannesburg, Marco Andreoli of the South African Nuclear Energy Corp. and Chris Harris of the University of Cape Town led the research.

“Never before in history has material from a comet been found on Earth,” Block said in the statement.

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