http://www.newsweek.com/2023/02/10/mysterious-green-comet-nears-earth-revealing-secrets-time-space-1776272.html

The new comet that's appeared in the night sky between the Big and Little Dippers is no visual extravaganza. To the unaided eye, it's just a small, green-tinged blob—nothing like Halley's Comet of 1910, whose tail stretched two-thirds of the way across the sky. And it will pass quickly, fading from view a week or two after reaching peak brightness in early February—a far cry from, say, Hale-Bopp's recording-breaking 15 months in the sky in 1997.

This comet, though, differs from the others in one important respect: it has traveled a much greater distance to get here. Although scientists are still trying to pin down details of where it came from and where it's headed, they reckon it takes 50,000 years to complete a round trip. (Hale-Bopp takes about 2500 years, Halley a mere 76.) That places its origin at the edge of the solar system, on the brink of interstellar space.