Scientists find out how the asteroid belt attacked dinosaurs


How do you track an asteroid that hit Earth over 60 million years ago? Using a combination of geology and computer simulations, at least according to a team of scientists from the Southwest Research Institute (SwRI). These methods may have enabled them to solve a long-standing mystery in archeology and astronomy: Where did the asteroid that killed the dinosaurs come from?

The fact that an asteroid impact was the disaster that ultimately killed the dinosaurs is now widely accepted in scientific circles. Now known as the “Chicxulub Event”, it takes its name from the 145 km wide crater in the Yucatan Peninsula that the 10 km wide asteroid caused when it struck the planet ago. about 66 million years old.

When an asteroid hit the Yucatan region around 66 million years ago, it triggered the extinction of the dinosaurs. The depiction of this artist is a great exaggeration of the actual size of the 10 km wide object, but shows the force that such an impact could have.
Credit: NASA / Don Davis

Large creatures like dinosaurs that evolved and ruled the Earth for hundreds of millions of years, shows that such large impacts were not very common in their time – so where did the impactor come from? Turns out it was probably from the outer asteroid belt.

Two main findings led to this conclusion – the first was geological samples taken from rocks formed at the time of impact. The second was a detailed model of different types of asteroids and comets and how they might interact with the different forces at play in the asteroid belt.

UT Asteroid Defense Video Part 1

It is not easy to obtain geological samples that are sixty-six million years old, but the SwRI team succeeded and noticed similarities in the composition of the rock they contained. He indicated that the Chicxulub impactor was a “carbonaceous chondrite” asteroid, which is a common type of asteroid, many of which pass close to Earth. The only difference is that none of them come close to the scale of the 10 km wide asteroid Chicxulub.

So the question always arose, where did such a large asteroid come from? To find out, SwRI researchers turned to mathematical models and a supercomputer. Using NASA’s Pleaides supercomputer, the team developed a model of 130,000 different asteroid types and observed their interaction with a much more comprehensive set of modeled forces in the asteroid belt.

UT Asteroid Defense Video Part 2

They discovered that thermal forces from the sun, along with the gravitational forces of other asteroids, can propel asteroids in the Outer Belt into a position known as a “dynamic escape hatch,” where a fast gravitational tug can. cause the object to fall. towards Earth orbit. This type of gravitational breakout has occurred relatively often in the model about once every 250 million years for an asteroid the size of the Chicxulub impactor. This is about 10 times more frequently than previously thought.

The team also realized that the class of carbonaceous chondrite asteroids that Chicxulub belonged to were much more common in the Outer Belt, and therefore more likely to venture into one of these dynamic escape hatches. So, it appears that the asteroid that killed the dinosaurs was a relatively rare large object thrown into the inner solar system by a confluence of gravitational and thermal forces. There are other explanations as well, such as a Harvard study which indicated that the source of the impactor was at the far reaches of the solar system, and another SwRI study which suggests that the disintegration of a larger asteroid might have caused it.

Harvard research offers a competing theory – that the impactor came from the edge of the solar system.
Credit – Harvard University YouTube Channel

All of this doesn’t sound particularly reassuring, given the possibility that a similar impact today will likely wipe out most of humanity. But, we still have nearly 200 million years before this happens again. And this time around, Earth has a defense mechanism it didn’t have last time around – a species that knows what to watch out for and potentially how to prevent such an impact from happening again.

Learn more:
arXiv – Dark primitive asteroids account for a large portion of K / Pg scale impacts on Earth
Sci-News – Dinosaur-killer asteroid Chicxulub came from outer part of main belt, study finds
Indian Express – Where did the dinosaur killer asteroid Chicxulub come from?

Main picture:
Artist design of the impact of the Chicxulub dinosaur that killed the dinosaurs.
Credit – SwRI / Don Davis

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