interstellar comet 3i atlas
Definition
3I/ATLAS, also known as C/2025 N1 (ATLAS), is the third confirmed interstellar comet observed passing through the Solar System, discovered on July 1, 2025, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Chile.
It follows an unbound hyperbolic trajectory with an eccentricity of 6.139 and a hyperbolic excess velocity of 58 km/s, confirming its origin from outside our Solar System.
The active comet features a reddish coma rich in CO₂ and dust, with a nucleus diameter estimated between 0.32 and 5.6 km, and will reach its closest approach to Earth on December 19, 2025, at about 1.8 AU.
Examples
Astronomers are glued to their telescopes as interstellar comet 3I/ATLAS makes its solar system debut, outpacing even the most caffeinated coffee runs at 58 km/s.
Interstellar comet 3I/ATLAS, with its CO₂ belch of a coma, is reminding us that some guests from afar come bearing cosmic flatulence.
While 'Oumuamua played hard to get, interstellar comet 3I/ATLAS is putting on a show with its dusty tail, proving not all interstellar visitors are shy.
Interstellar comet 3I/ATLAS swung by Mars like a cosmic tourist snapping selfies, before heading Earthward for a distant wave on December 19.