When you hear that a giant, icy mass hurtling through space has entered our solar system, your mind might leap straight to aliens — and for some scientists, that possibility isn't entirely out of the question.
Harvard astrophysicist Avi Loeb has spent months analysing 3I/ATLAS, a comet-like object from beyond the solar system that passed Earth shortly before Christmas. While most astronomers see a frozen mass of dust and gas, Loeb suggests it could be something more provocative: a messenger, or even a machine, from another civilisation.
