The extinction of the dinosaurs brought to the forefront the idea of celestial bodies -- such as meteorites -- impacting the Earth's surface. Now a group of scientists has reported definitive evidence of a comet colliding with our planet.
The team concluded, after a battery of analyses, that a mysterious dark pebble found in the Egyptian desert several years ago is in fact a fragment from a cometary nucleus. That cometary pebble has been christened eponymously after the ancient female philosopher, mathematician, and astronomer named Hypatia of Alexandria.
Lead author Jan Kramers, from South Africa's University of Johannesburg enthusiastically shared the following: "It's...scientific euphoria when you eliminate all other options and come to the realization of what it must be."
Interestingly, the dark stone is studded with diamonds, which is no surprise, considering its cometary roots. "Diamonds are produced from carbon-bearing material," Kramers informed. "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 comet's collision with Earth is estimated to have occurred roughly 28 million years ago over what is now Egypt. While entering our planet's atmosphere, the comet likely heated up to about 2000 degrees Celsius (3630 degrees Fahrenheit) and thereby showered silica glass across the Sahara Desert. One piece of this silica glass eventually became part of a celebrated brooch owned by the famed Pharoah Tutankhamen.
Prior to Hypatia, it had long been circulated in scientific circles that comets likely collided with Earth during our planetary past. However, previous research had only arrived at mere specks in the upper atmosphere and tiny particles in the Antarctic ice as cometary substances. Now, groundbreaking work on comets is highly anticipated with the discovery of Hypatia, a sizable pebble by comparison -- thus, clearly making Hypatia leave all other specimens in the dust, so to speak.
"NASA and ESA (European Space Agency) spend billions of dollars collecting a few micrograms of comet material and bringing it back to Earth, and now we've got a radical new approach of studying this material, without spending billions of dollars collecting it," Kramers said.