By comparing our local Comet Hale-Bopp to the interstellar visitor 2I/Borisov, a team of astronomers have concluded that the interloper is perhaps one of the most pristine comets we’ve ever seen. “2I/Borisov could represent the first truly pristine comet ever observed,” says Stefano Bagnulo of the Armagh Observatory and Planetarium, Northern Ireland, UK, who led the … Continue reading Interstellar Comet Borisov is so Pristine, it’s Probably Never Been Close to a Star Before