The asteroid that set into motion a series of events that led to the extinction of the dinosaurs occurred at the "deadliest possible angle," a team of researchers has concluded.
As CNN reported, scientists have known for decades that the dinosaurs went extinct thanks to a dramatic and almost-instantaneous (in geological terms) climate-change event. That event occurred approximately 66 million years ago, when a "city-sized" asteroid struck the Earth, creating the 125-mile-wide Chicxulub crater in present-day Mexico.
The cataclysmic event caused a series of smaller incidents that eventually led to the extinction of the dinosaurs, in addition to wiping out three quarters of life on the planet. Putting aside the immediate results of the impact, such as the intense heat in the region where it landed and the subsequent shock waves, the strike also kicked up debris and gases into the atmosphere that led to a so-called nuclear winter, when global temperatures cooled and the amount of sunlight reaching the earth was reduced.
While the general outline of the event has been understood for several decades, the specifics have eluded researchers. In particular, the angle at which the asteroid hit the earth -- and the direction from which it came -- has been a matter of dispute.
A team of researchers affiliated with Imperial College London's department of earth science and engineering has used computer simulations to posit that the asteroid came in from the northeast and struck the ground at an angle somewhere between 40 and 60 degrees.
"The asteroid strike unleashed an incredible amount of climate-changing gases into the atmosphere, triggering a chain of events that led to the extinction of the dinosaurs. This was likely worsened by the fact that it struck at one of the deadliest possible angles," said Gareth Collins, a professor of planetary science and the lead author of the study.
Collins noted that the angle of impact put more hazardous material into the atmosphere than would have otherwise occurred with an impact at a different angle.
Beyond computer modeling, the team also looked at the crater itself -- specifically its shape and its secrets, buried in the rocks underneath it.
"Despite being buried beneath nearly a kilometer of sedimentary rocks, it is remarkable that geophysical data reveals so much about the crater structure — enough to describe the direction and angle of the impact," said Auriol Rae, a postdoctoral researcher at the University of Freiburg and a coauthor of the study.
Asteroids have bedeviled the earth throughout its 4 billion years of existence, shaping its geography, its climate, and its history. While history-changing asteroid impacts are not believed to have occurred since homo sapiens emerged approximately 200,000 years ago, potentially life-destroying asteroids zip past the planet on an almost daily basis, some coming perilously close to making impact.