Astronomers from ESA’s Near-Earth Object Coordination Centre (NEOCC), part of the Agency’s Planetary Defence Office, made these observations of the newly discovered interstellar comet 3I/ATLAS on 2 July 2025.
The comet is only the third of its kind ever observed, following the famous 1I/ʻOumuamua in 2017 and 2I/Borisov in 2019.
It was first spotted on 1 July 2025 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Río Hurtado, Chile. Its unusual trajectory immediately raised suspicions that it originated from interstellar space. This was later confirmed by astronomers around the world, and the object was given its formal designation: 3I/ATLAS, indicating its status as the third known interstellar object.
As of 3 July, 3I/ATLAS is approximately 670 million kilometres from the Sun and will make its closest approach in late October 2025, passing just inside the orbit of Mars. It is thought to be up to 20 kilometres wide and is travelling roughly 60 km/s relative to the Sun. It poses no danger to Earth, coming no closer than 240 million kilometres – over 1.5 times the distance between Earth and the Sun.
The observations were made using the Las Cumbres Observatory telescope in Hawaii, one of the telescopes on which ESA astronomers are allocated dedicated observing time.