3I/ATLAS is only the third confirmed interstellar object ever detected passing through our solar system. It may be older than the Sun itself, and Webb observations show it is carrying an unusually carbon dioxide-rich coma as it swings past once before leaving for interstellar space forever.

On 1 July 2025, the ATLAS survey in Chile picked up a faint object moving on a path that did not belong to the solar system. Within days it was confirmed as 3I/ATLAS, only the third known interstellar object identified passing through our system, after 1I/’Oumuamua in 2017 and 2I/Borisov in 2019. It is a [...] The post 3I/ATLAS is only the third confirmed interstellar object ever detected passing through our solar system. It may be older than the Sun itself, and Webb observations show it is carr