3I/ATLAS, also known as C/2025 N1 (ATLAS) and previously as A11pl3Z, is an interstellar comet discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) station at Río Hurtado, Chile, on 1 July 2025. When it was discovered, it was entering the inner Solar System at a distance of 4.5 AU (670 million km; 420 million mi) from the Sun. The comet follows an unbound, hyperbolic trajectory past the Sun with a very fast hyperbolic excess velocity of 58 km/s (36 mi/s) relative to the Sun. 3I/ATLAS will not come closer than 1.8 AU (270 million km; 170 million mi) to Earth, so it poses no threat.^[18] It is the third interstellar object confirmed passing through the Solar System, after 1I/ʻOumuamua (discovered in October 2017) and 2I/Borisov (discovered in August 2019), hence the prefix “3I”.