Chicxulub asteroid: Where did the asteroid that killed dinosaurs million years ago come from?

The findings states that 10-km-wide asteroids from the outer half of the asteroid belt can hit Earth once every 250 million years on an average (Photo: SwRI/Don Davis)

Some 66 million years ago, a large asteroid, about 10-km-wide, hit the Earth. The large asteroid hit the ground near Mexico which further created a 180-kilometre-diameter impact structure on the earth. The event resulted in a mass extinction event wiping out 75 per cent of all animal and plant species including non-avian dinosaurs from the planet.

With the help of various findings on asteroid evolution and data extracted from known asteroids, US team dug a little deeper into this very asteroid named Chicxulub (the one which destroyed dinosaurs)– like where this asteroid came from, how often such events have occured in the past and other related details. The results of the study were published in Icarus last month.

Dr David Nesvorný, the lead author of the study, in a press release said, “We decided to look for where the siblings of the Chicxulub impactor might be hiding.” The team had studied the main asteroid belt which is located between the orbits of Mars and Jupiter. NASA reveals, this belt is estimated to have between 1.1 and 1.9 million asteroids larger than 1 kilometre in diameter followed by millions of smaller ones.

With the help of computer models, the authors studied how objects escape from this belt. They noted how thermal forces can allow these objects to drift and how gravitational kicks from both the planets (Mars and Jupiter) can push the object into orbits near the blue planet (Earth).

Over 100,000 such asteroids were studied by the team with the help of NASA’s Pleiades Supercomputer. The findings stated that 10-km-wide asteroids from the outer half of the asteroid belt can hit Earth once every 250 million years on an average– which is at least 10 times more often than previously calculated.

Dr. Simone Marchi, co-author of the study, said “This result is intriguing not only because the outer half of the asteroid belt is home to large numbers of carbonaceous chondrite impactors, but also because the team’s simulations can, for the first time, reproduce the orbits of large asteroids on the verge of approaching Earth.”“Our explanation for the source of the Chicxulub impactor fits in beautifully with what we already know about how asteroids evolve,” he added.

“This work will help us better understand the nature of the Chicxulub impact, while also telling us where other large impactors from Earth’s deep past might have originated,” Dr Nesvorný added.