The biggest comet ever discovered by scientists has been spotted in our solar system–and it’s coming this way, according to NASA.
The behemoth, which NASA calls the C/2014 UN271 (Bernardinelli-Bernstein) comet (rolls off the tongue doesn’t it?), is a staggering 128 km across–80 miles–with a nucleus about 50 times larger than a normal comet. That makes it four times the size of Bahrain.
It’s also coming towards us at 22,000 miles an hour–35,405 km/h–with a mass of 454 trillion metric tonnes. It should be closest to us by 2031.
Breathe a sigh of relief though–there is some good news. It’s currently on coarse to never reach more than one billion miles from Earth, basically reaching as far away as Saturn.
Still, a comet this big is cause for pause. The previous biggest comet was discovered 20 full years ago in 2002 by Lincoln Near-Earth Asteroid Research, or the LINEAR project. That comet was comet C/2002 VQ94.
Ok here’s the potentially worrying news–there’s many more yet to be discovered lurking just outside the solar system.
“This comet is literally the tip of the iceberg for many thousands of comets that are too faint to see in the more distant parts of the solar system,” said David Jewitt, a professor of planetary science and astronomy at the University of California, Los Angeles (UCLA), and co-author of the new study in The Astrophysical Journal Letters.
“We’ve always suspected this comet had to be big because it is so bright at such a large distance. Now we confirm it is.”
How the comet was discovered
Comet C/2014 UN271 was discovered by astronomers Pedro Bernardinelli and Gary Bernstein in archival images from the Dark Energy Survey at the Cerro Tololo Inter-American Observatory in Chile.
By sheer coincidence, it was spotted in November 2010, when it was a whopping 3 billion miles from the Sun, which is nearly the average distance to Neptune. Since then, it has been intensively studied by ground and space-based telescopes–and the results have finally been released.
“This is an amazing object, given how active it is when it’s still so far from the Sun,” said the results’ lead author Man-To Hui of the Macau University of Science and Technology, Taipa, Macau.
“We guessed the comet might be pretty big, but we needed the best data to confirm this.”
So, his team used Hubble to take five photos on January 8, 2022.
This comet has been travelling for quite a while. According to NASA, it’s been falling towards the sun for over 1 million years from the Oort Cloud, the hypothesized (but yet to be actually spotted) nesting ground for literally trillions–yes trillions–of others. The Oort cloud is thought to be around 20 times the size of Earth.
Why there’s more comets to come
They were actually formed not so far from the son, but were tossed out of the solar system billions of years ago when Jupiter and Saturn were still developing their orbits due to what is described as a gravitational ‘pinball game’.
Some of those then travel back to the Sun–and towards us–if their orbit is distrubed the the gravitational tug of another passing star.
The Oort Cloud–and the trillions that could still be headed towards us–seems like it definitely exists.
According to NASA, the reality of the Oort Cloud is bolstered by theoretical modeling of the formation and evolution of the solar system. The more observational evidence that can be gathered through deep sky surveys coupled with multiwavelength observations, the better astronomers will understand the Oort Cloud’s role in the solar system’s evolution–meaning we’ll get proof at some point.
In the mean time, keep an eye on the skies, as comets and asteroids have been known to sneak up on us before.