Asteroid That Killed Dinosaurs 66 Million Years Ago Wasn’t Alone, Scientists Determine

The giant asteroid that hit Earth and wiped out the dinosaurs 66 million years ago was not alone, scientists have confirmed. A second, smaller space rock crashed into the sea off the coast of West Africa, creating a large crater around the same time, according to the BBC.

According to scientists, it would have been a “catastrophic event”, which would have caused a tsunami of at least 800 meters high, which would have crossed the Atlantic Ocean. Dr. Uisdean Nicholson of Heriot-Watt University first discovered Nadir Crater in 2022, but a cloud of uncertainty hung over how it actually formed.

Dr. Nicholson and his colleagues are now certain that the 9 kilometer depression was caused by an asteroid hitting the sea floor.

They cannot give the exact date of the event, nor can they say whether it occurred before or after the asteroid that left Mexico’s 180-kilometer-wide Chicxulub crater. That ended the reign of the dinosaurs.

But researchers say the smaller rock also appeared at the end of the Cretaceous period, when the dinosaurs disappeared. When it crashed into Earth’s atmosphere, it would have formed a fireball.

“Imagine the asteroid hits Glasgow and you’re in Edinburgh, about 50 kilometers away. The fireball would have been about 24 times the size of the Sun in the sky – enough to set trees and plants in Edinburgh on fire,” says Dr Nicholson.

An extremely powerful blast of air would have followed, before a seismic tremor the size of a magnitude 7 earthquake. Huge amounts of water likely left the sea floor and then cascaded down, creating unique footprints on the ground.

It is unusual for such large asteroids to crash out of our solar system in the direction of our planet within a short time of each other. But researchers don’t know why two hit Earth so close to each other.

The asteroid that created the Nadir crater was about 450-500 meters wide, and scientists believe it hit Earth at about 72,000 kilometers per hour.

The closest humans came to an event of this magnitude was the Tunguska event of 1908, when a 50-meter asteroid exploded in the Siberian sky.

Another asteroid could hit Earth in 2182

Asteroid Nadir was about the size of Bennu, which is currently the most dangerous near-Earth object.

Scientists say the most likely date Bennu could hit Earth is September 24, 2182, according to NASA. But that’s still only a 1 in 2,700 chance.

There has never been an asteroid impact of this size in human history, and scientists normally have to study eroded craters on Earth or images of craters on other planets.

To better understand Nadir Crater, Dr. Nicholson and his team analyzed high-resolution 3D data from a geophysical company called TGS.

Most craters are eroded, but this one was well preserved, meaning scientists could look further into the rock levels.

“It’s the first time we’ve been able to see the inside of an impact crater like this – it’s very exciting,” says Dr Nicholson, adding that there are only 20 marine craters in the world, but none have been studied in as much detail as this one.

The findings are reported in Nature Communications Earth & Environment.