Scientists Uncover First Ever Evidence of Exploding Comet Striking Earth
Scientists have uncovered the first ever evidence of an ancient comet that entered Earth's atmosphere before exploding in a spectacular display. The resulting shock wave rained down a wave of fire which obliterated almost every life form in its path. The findings may help researchers unlock the secrets of the formation of our solar system.
Comet material is generally elusive. Fragments of comets actually haven't been found on Earth, except for microscopic sized dust particles in the upper atmosphere and some carbon-rich dust in the Antarctic ice. In fact, both NASA and ESA spend billions of dollars collecting a few micrograms of comet material to bring back to Earth. This new finding, though, changes all that.
About 28 million years ago, the comet in question entered Earth's atmosphere above what is now Egypt. As it approached our planet, it exploded and heated up the sand beneath it to temperatures of about 2,000 degree Celsius. This resulted in the formation of a large amount of yellow silica glass which lies scattered over a 6,000 square kilometer area in the Sahara.
Years earlier, an Egyptian geologist discovered a mysterious black pebble in the area where the silica glass can be found. The researchers decided to conduct chemical analyses on this pebble and found that it represented the very first known hand specimen of a comet nucleus. The researchers also found that the impact of the explosion produced microscopic diamonds in the pebble.
"It's a typical scientific euphoria when you eliminate all other options and come to the realization of what it must be," said Jan Kramers, one of the researchers, in a news release. "Diamonds are produced from carbon bearing material. Normally they form deep in the Earth, where the pressure is high, but you can also generate very high pressure with shock. Part of the comet impacted and the shock of the impact produced the diamonds."
The new finding actually allows scientists to better understand comets that might have impacted Earth. It provides researchers a good chunk of material to analyze and study, which could lead to future findings.
"Comets contain the very secrets to unlocking the formation of our solar system and this discovery gives us an unprecedented opportunity to study comet material first hand," said David Block, one of the researchers, in a news release.
The findings are published in the journal Earth and Planetary Science Letters.