You might be surprised as to the origin of Earth’s asteroids

3 Jul 2018

Image: Johan Swanepoel/Shutterstock

A surprising study looking into the origin of asteroids and meteorites that collide with Earth has found that the vast majority come from a small selection of ancient planets.

As astronomers try to piece together the mysterious origins of the comet ‘Oumuamua, a team of researchers from the University of Florida believes it has found the origin of other cosmic objects in our solar system, specifically asteroids and meteorites that have struck Earth.

While we know that the main source of Earth’s meteorites is the inner asteroid belt, the research team has found that the vast majority of them are the result of a splintering of only five or six ancient, minor planets aeons ago.

In a paper published to Nature Astronomy, the team estimated that at least 85pc of the 200,000 or so asteroids in the inner belt were created as a result of this process, but the remaining 15pc may trace their origins to the same group of primordial bodies.

This somewhat surprising finding will be important for our understanding of how our own rocky planet came to be. Perhaps even more crucially, it could prove essential in how we might be able to protect ourselves against a planet-killing asteroid on a collision course with Earth.

‘We need to know what its nature is’

“These large bodies whiz by the Earth, so of course we’re very concerned about how many of these there are and what types of material are in them,” said Stanley Dermott, lead author of the study.

“If ever one of these comes towards the Earth and we want to deflect it, we need to know what its nature is.”

Dermott and his team were also able to demonstrate that the type of orbit an asteroid has depends on the size of the latter.

This suggests that differences in meteorites found on Earth appear because of the evolutionary changes that occurred inside a few large, precursor bodies that existed more than 4bn years ago.

“I wouldn’t be surprised if we eventually trace the origins of all asteroids in the main asteroid belt, not just those in the inner belt, to a small number of known parent bodies,” Dermott added.

Colm Gorey was a senior journalist with Silicon Republic