A 93-mile comet - considered "perhaps the largest comet ever seen" - is set to enter our solar system in the next 10 years, according to astronomers. The C/2014 UN271 comet, also known as Bernardinelli-Bernstein, will come around as close to Earth as Saturn is on 21 January 2031, National Geographic reports. Gary Bernstein, who co-discovered the comet, said: "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."