Scientists have confirmed that the asteroid that wiped out the dinosaurs 66 million years ago was not the only one. A second, smaller asteroid crashed into the sea off the coast of West Africa, causing a massive tsunami and leaving a 9-kilometer crater, UNN reports with reference to the BBC.
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Dr. Wisdin Nicholson of Heriot-Watt University first discovered Nadir Crater in 2022, but it remained unknown for a long time how it was formed.
Now, after research, scientists are confident that this 9-kilometer crater was the result of an asteroid hitting the seafloor. Although they cannot determine for certain whether this was before or after the asteroid impact that created the Chicxulub crater in Mexico that ended the dinosaur era, scientists are confident that a smaller asteroid also arrived at the end of the Cretaceous Period, causing a fireball as it entered the Earth's atmosphere.
"Imagine an asteroid hitting Glasgow and you're in Edinburgh, about 50 kilometers away. The fireball would be about 24 times the size of the Sun in the sky - enough to burn the trees and plants in Edinburgh," says Dr. Nicholson.
After the asteroid impact, a powerful explosion in the air would have occurred, followed by seismic tremors similar to a magnitude 7 earthquake. Large amounts of water probably rose from the seafloor and cascaded back down, leaving unique marks on the bottom. It is unusual for two such large asteroids to hit the Earth one after the other within a short time, and scientists cannot explain exactly why this happened.
The asteroid that created the Nadir crater was approximately 450-500 meters in size and is estimated to have hit the Earth at a speed of about 72,000 km/h. An event of this magnitude was similar to the Tunguska explosion of 1908, when a 50-meter asteroid exploded over Siberia. The Nadir asteroid is comparable in size to the Bennu asteroid, which is currently the most dangerous object orbiting the Earth. According to NASA, there is a 1 in 2,700 chance that Bennu could collide with our planet on September 24, 2182.
There has never been an impact with an asteroid of this size in human history, so scientists usually study eroded craters on Earth or images of craters on other planets. To better understand Nadir Crater, Dr. Nicholson and his team examined high-resolution 3D data provided by the geophysical company TGS. The crater is well-preserved, giving scientists the opportunity to examine different rock layers in detail.
"This is the first time we've been able to look inside an impact crater like this - it's very exciting," says Dr. Nicholson, adding that there are only 20 sea craters in the world, but none of them have been studied in as much detail as this one.
Recall
A new study suggeststhat about 466 million years ago, the Earth may have been surrounded by a giant ring of space debris similar to that of Saturn.