Last Updated on August 9, 2021 by MyGh.Online
Scientists say it was a “dark asteroid” that killed the dinosaurs after smashing into Earth 66 million years ago.
They reckon the six-mile space rock came from the outer edges of the asteroid belt between Mars and Jupiter, LiveScience reports.
The region is full of asteroids that reflect very little light, research from the Southwest Research Institute in Colorado said.
Study leader David Nesvorný said: “I had a suspicion that the outer half of the asteroid belt — that’s where the dark primitive asteroids are — may be an important source of terrestrial impactors.
“But I did not expect that the results [would] be so definitive.”
The space rock that ended the reign of non-flying dinosaurs has been found buried in the Chicxulub crate in Mexico.
There is a 90-mile wide circular scar in the country’s Yucatan Peninsula left from the massive impact.
Tests at the site have suggested that the space object was part of a class of carbonaceous chondrites — a primitive group of meteorites that have a relatively high ratio of carbon and were likely made very early on in the solar system’s history.
Scientists have used this to try to pinpoint the impactor’s origin, but many theories have crumbled over time.
One suggested it came from a family of asteroids from the inner part of the main asteroid belt, but follow-up observations of those asteroids found they didn’t have the right composition.
Another study, this one published in February in the journal Scientific Reports, suggested the impact was caused by a long-period comet, Live Science reported.
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But that research has since come under criticism, according to a June paper published in the journal Astronomy & Geophysics.
Now the new study, published in the November 2021 issue of the journal Icarus, sees researchers develop a computer model to see how often main belt asteroids escape toward Earth and if such escapees could be responsible for the dinosaur-ending crash.
Simulating over hundreds of millions of years, the model showed thermal forces and gravitational tugs from planets periodically slingshotting large asteroids out of the belt.
On average, an asteroid more than 6 miles wide – the size of the dino-killing asteroid – from the outer edge of the belt was flung into a collision course with Earth once every 250 million years, the researchers found.
This calculation makes such an event five times more common than previously thought.
The model also showed half of the expelled asteroids were the dark carbonaceous chondrites, which matches the type thought to have caused Chicxulub crater.
“This is just an excellent paper,” said Jessica Noviello, NASA fellow in the postdoctoral management program at the Universities Space Research Association at Goddard Space Flight Center, who was not involved with the new research.
“I think they make a good argument for why [the Chicxulub impactor] could have come from that part of the solar system.”