How an Ancient Comet Collision Could Have Caused Global Warming 56 Million Years Ago

A team of scientists has identified the first-ever evidence of a comet colliding with planet Earth about 56 millions of years ago. The study suggests that during the comet collision, the Earth experienced an abrupt warming period or Paleocene-Eocene Thermal Maximum (PETM), showing that the catastrophic event could have lead to an ancient global warming.

According to the study published in the journal Science, the scientists found Glassy silica spherules in marine sediments or ocean rocks located in three areas off the Atlantic coast. The said glassy spherules are leftover rock debris during an extraterrestrial impact, such as a comet or asteroid hitting Earth.

The glassy spherules form when drops of molten rock from a comet collision fall to the Earth where they freeze, creating what look like glassy spheres. The researchers also found that these rock samples is a form of quartz. To note, a rock only becomes quartz when applied with a high amount of pressure such as an impact.

Assistant Professor Morgan Schaller from Rensselaer Polytechnic Institute told The Verge in an interview that the discovery of the glassy spherules is the first ever solid evidence that a comet impact happened 56 million years ago.

"There’s never really been any firm physical evidence of that happening. But this is the first evidence of an impact at this time for sure," he said.

The Paleocene-Eocene Thermal Maximum has greatly affected the Earth -- from its geographical make-up to the animals thriving before that time. In fact, PETM's impact on the planet was so drastic that it turned everything upside down, making Antarctica into a lush tropical region and causing mass extinctions on various species.

Scientists say that the cause of PETM has been shrouded in mystery, but the recent findings give clues that the comet impact and the warming period on Earth could be linked.

"There are a lot of impacts through history, but that it seems to coincide so precisely with this global warming event is a tantalizing coincidence," Schaller said.

He further said that further understanding of what happened during PETM is important in understanding the current global warming that the Earth experiences today.