How 2025 became the year of comet: The rise of interstellar 3I/ATLAS, an icy Lemmon and a cosmic SWAN

A bright green comet is pictured to the bottom left of a starfield against a black sky, with a long tail extending to the upper right of the screen.

2025 has seen stargazers look on in awe as a trio of magnificent comets barreled headlong into the inner solar system to survive a close brush with the sun, only to emerge to race back out into the blackness of space, never to be seen again.

Of these comets — the interstellar invader 3I/ATLAS, C/2025 A6 (Lemmon) and C/2025 R2 (SWAN) — not all survived their trial by solar radiation intact, while others drew the attention of a global audience thanks in part to their scientific significance and in some cases, the disinformation that swirled around them.