Water detected on interstellar comet

Astronomers have spotted signs of water spraying off comet 2I/Borisov as it flies towards the Sun on a journey from interstellar space. It’s the first time scientists have seen water in our Solar System that originated elsewhere. Most comets contain a lot of water, but confirming its presence in an interstellar comet is an important step towards understanding how water might travel between the stars. Astronomers have been tracking Borisov since its discovery in August. It is only the second interstellar object ever discovered, after 2017’s Oumuamua.