Space & Astronomy

Arrokoth rewrites theory of planet formation

By T.K. Randall
February 17, 2020 ·  2 comments

This distant body has taught scientists a great deal. Image Credit: NASA / Johns Hopkins University With a mass approximately 10,000 times that of the comet visited by ESA's Rosetta spacecraft, 486958 Arrokoth (previously known as Ultima Thule) is around 30 miles in diameter and orbits the Sun once every 295 years.

Until relatively recently, no spacecraft had ever visited this - or any other - object situated so far out in the solar system, but now thanks to the New Horizons probe, scientists have been able to take a close-up look at this enigmatic object and their findings have been groundbreaking to say the least.

High-resolution images of Arrokoth show that it actually consists of two objects that once collided and combined to form a single larger object. The big question however is exactly how the two constituent parts came together - did they collide violently or was it a more gentle process ?Now at last it can be revealed that scientists have found no evidence of a violent impact, meaning that the traditional view that the planets formed through a series of violent collisions is likely to be incorrect.

"There was the prevailing theory from the late 1960s of violent collisions and a more recent emerging theory of gentle accumulation," said study lead researcher Dr Alan Stern.

"One is dust and the other is the only one standing. This rarely happens in planetary science, but today we have settled the matter. This is completely decisive."

"In one fell swoop, the flyby of Arrokoth was able to decide between the two theories."

Source: BBC News | Comments (2)

Tags: Planet, New Horizons