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We just learned new details about the cataclysmic event that killed the dinosaurs

Published May 27th, 2020 10:06AM EDT
dinosaur asteroid
Image: Carlos Tischler/Shutterstock

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  • The asteroid that killed the dinosaur struck the Earth at the worst possible angle for the species living here at the time.
  • Advanced modeling reveals that the rock likely struck at an angle of between 60 and 75 degrees, maximizing the amount of hot gas released into the atmosphere.
  • The impact resulted in the death of approximately 75% of all species on Earth.

When the asteroid that created the Chicxulub crater struck Earth it was an absolutely devastating event. In fact, “devastating” might not even fully describe how destructive it was. Researchers believe it wiped out as much as 75% of all species on the planet. It’s one of the big reasons why we’re here today, but for the dinosaurs it was some pretty bad luck.

Now, a new study published in Nature Communications reveals just how unlucky the species on Earth truly were when that massive space rock arrived. It wasn’t just that the asteroid hit Earth or that it was particularly large — estimated to be as large as 50 miles in diameter — but based on new 3D computer modeling, it appears that the asteroid struck at the worst possible angle.

For the study, the researchers studied asymmetries in what remains of the impact crater the asteroid produced when it slammed into Earth. Like throwing a rock onto a sandy beach, you can tell a lot about the angle of impact based on the shape of the crater it produces.

After tens of millions of years, the crater is still visible but it’s obviously not as clear as it once was. The scientists studied the “subsurface structure” of the crater to get a better idea of how the asteroid struck the planet. This is important because it can reveal how devastating the impact was, as very steep or very shallow impacts are thought to be less destructive.

What the team found was that the rock probably struck the surface at an angle between 45 and 60 degrees. That’s basically a worst-case scenario for such an event, and it ensured the asteroid strike had the maximum effect.

“Comparison of 3D numerical simulations of Chicxulub-scale impacts with geophysical observations suggests that the Chicxulub crater was formed by a steeply-inclined (45–60° to horizontal) impact from the northeast; several lines of evidence rule out a low angle (<30°) impact,” the study reads. “A steeply-inclined impact produces a nearly symmetric distribution of ejected rock and releases more climate-changing gases per impactor mass than either a very shallow or near-vertical impact.”

It’s impossible for us to know how things might have played out differently if the asteroid had approached at a different, less destructive angle. Would the aftermath have been less lethal to the dinosaurs and other ancient species? Would dinosaur have continued to dominate the Earth, preventing the rise of mammals (and us)? We can’t know for sure, but it’s kind of crazy to imagine it.

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