The Interstellar Comet That’s Spilling Its Secrets

Astronomers have measured water streaming from interstellar comet 3I/ATLAS for the first time since it passed closest to the Sun. Using a spacecraft that’s been watching the Sun for nearly three decades, scientists detected hydrogen glowing around the comet and calculated that it was producing water at extraordinary rates. These measurements not only confirm that interstellar comets behave remarkably like our own Solar System’s icy wanderers, but also provide crucial clues about what comets looked like in the early universe.