An enormous comet — possibly the largest one ever detected — is barreling toward the inner solar system with an estimated arrival time of 10 years from now, according to new research published on the preprint server arXiv.org.
The comet, known as the Bernardinelli-Bernstein comet (or C/2014 UN271, in astro-speak), is at least 62 miles (100 kilometers) across — about 1,000 times more massive than a typical comet. It’s so large that astronomers previously mistook it for a dwarf planet, according to a statement announcing the comet’s discovery in June 2021.
But a closer analysis of the object revealed that it was moving rapidly through the Oort cloud — a vast scrapyard of icy rocks, billions of miles from Earth. The object appeared to be headed our way, and it even had a glowing tail, or "coma", behind it — a clear indication of an icy comet approaching the relatively warm inner solar system.
