In 2020, a recently discovered comet was seen splitting in two – and now astronomers think they know why.
The comet, C/2018 F4, is thought to have originated in the Oort cloud. Often described as a ‘cometary reservoir’, Oort’s presence is still theoretical – it is a predicted collection of icy objects starting around 186trillion miles from Earth, well beyond Pluto.
Traversing the solar system during a 300,000year round trip, C/2018 F4 broke up as it reached its closest point to the centre, around three times the distance between the Earth and the Sun.
A team led by Man-To Hui at the Macu University of Science and Technology in China have used telescopes around the world to determine the two factors that led to its dramatic split.
Imaging suggests the comet wasn’t a typical round object, but had two lobes connected by a thinner neck, also known as a bilobate shape.
As the comet approached the Sun it began heating up, possibly ejecting material that caused it to begin spinning. The rapid rotation, combined with its unusual shape, led to the two halves to break up and go their separate ways.
‘There’s a point at which it is rotating so quickly, the two main components can’t stick together any more, so they separate,’ said team member Michael Kelly, speaking to Metro.co.uk’s sister publication New Scientist.
The mystery cloud
The Oort cloud is thought to lie between 2,000 and 100,000 astronomical units (AU) from the Sun – where 1AU is the distance between Earth and the Sun, about 93million miles.
Although it has never been seen, its presence explains observations of comets within the planetary region of the solar system.
Voyager 1, the most distant human made object in space, is still about 300 years from reaching the Oort cloud – despite travelling about a million miles per day.
Source: Nasa
The point shortly after the split has been captured as two bright balls of light, close together in cosmic terms but moving apart at a rate of about 3metres per second. The two halves are now about 400,000kilometres away from each other.
‘Future astronomers may not even know they were related,’ added Kelley, a research scientist at the University of Maryland.
Some astronomers predict one of the solar system’s most famous residents, Halley’s Comet, will also one day split in too – or evaporate entirely. However, this is expected to happen within the next few ‘tens of thousands of years’, so those hoping to spot it in 2061 are unlikely to be disappointed.
MORE : A comet’s death dive into the sun was captured on camera
MORE : Astronomers have spotted the biggest cosmic explosion ever seen
