Study challenges long-held beliefs about how Solar System was formed

A Western-led international team of researchers has confirmed that a fireball that originated at the edge of the Solar System was likely made of rock, not ice, challenging long-held beliefs about how our Solar System was formed.

Theoretically, the very basis of understanding the origins of our Solar System is built upon the foundation that only icy objects exist in these outer reaches and certainly, nothing made of rock.

However, this changed last year, when the international research team led by Western meteor physicists captured images and videos of a rocky meteoroid that flew through the skies over central Alberta as a dazzling fireball. They have since concluded all signs point to the object's origin being smack dab in the middle of the Oort Cloud - a predicted collection of icy objects farther away than everything else in the solar system.

The Western researchers used Global Meteor Network tools which were developed for the Winchombe fireball - a rare carbonaceous meteorite which crashed onto a driveway in Gloucestershire in 2021 - to calculate how the rocky fireball was travelling on an orbit usually reserved only for icy long-period comets from the Oort Cloud.

According to the researchers, the Alberta fireball descended much deeper into the atmosphere than icy objects on similar orbits and broke apart exactly like a fireball dropping stony meteorites – the necessary evidence that it was, in fact, made of rock.

"This discovery supports an entirely different model of the formation of the Solar System, one which backs the idea that significant amounts of rocky material co-exist with icy objects within the Oort cloud. This result is not explained by the currently favoured Solar System formation models. It's a complete game changer," said Denis Vida, a Western meteor physics postdoctoral researcher.

The findings were published today in Nature Astronomy. More details can be found here.