There's a massive space rock out there, one roughly the size of a dwarf planet, and it's likely headed towards our solar system.
While this sounds like the setup to a disaster movie, there's no reason to worry. Still, scientists are eagerly anticipating what could be a great opportunity to study something that's rarely seen.
It isn't the catchiest name, but those in the know don't really care.
It's set to whiz through our solar system just outside Saturn's orbit. That's close to a billion miles away, so Earth is safe.
"We have the privilege of having discovered perhaps the largest comet ever seen — or at least larger than any well-studied one — and caught it early enough for people to watch it evolve as it approaches and warms up," explained the comet's co-discovered, astronomer Gary Bernstein from the University of Pennsylvania.
As for why it's such a big deal, there are two factors: it's big, and it hasn't been seen before.
"Indeed, this may be the most pristine comet ever observed, in that we have detected it before it comes within Uranus's orbit, and it may never have done so on any previous orbit," said the authors of a paper on the comet.
It's about 96 miles in diameter, which isn't big in terms of the vastness of space, but is plenty big for a comet. Unfortunately, despite its size, it won't pass close enough to our planet to be visible to the naked eye.
This survey, which ran from August 2013 to January 2019, used infrared to observe the southern sky over the course of a few hundred nights.
The purpose of the DES was to measure the expansion of the universe, but it also helped discover objects like this comet.
These icy rocks hurtling through space are untouched, needless to say. That means they've remained in more or less the same state ever since the universe was formed 4.5 billion years ago. Scientists should be able to find out more about the chemistry of the universe during its formation.
It's a shame it won't be visible unless you have a telescope, but it should lead to some interesting finds for astronomers.
Let us know what questions about the universe you'd like answered in the comments below!
