In July 2025, sky-survey telescopes flagged a mysterious object streaking into our Solar System. Within days, scientists confirmed it was no ordinary comet but an interstellar visitor designated 3I/ATLAS (also known as C/2025 N1 ATLAS), only the third such object ever identified after 1I/'Oumuamua in 2017 and 2I/Borisov in 2019.
What makes 3I/ATLAS stand out is not merely its provenance beyond the Sun's domain, but its puzzling behaviour as it whips past our star, behaviour that has prompted some commentators to entertain the unlikely hypothesis that the object might be an alien spacecraft, or at least a highly anomalous natural body.
