It came from outer space. Interstellar space, to be precise. From somewhere beyond the influence of our sun, possibly from one of our Milky Way galaxy's most ancient stars, one that formed long before our own sun and solar system. We may never know for sure.
Interstellar comet 3I/ATLAS was discovered on July 1, 2025, by the NASA-funded ATLAS survey (Asteroid Terrestrial-impact Last Alert System) in Chile, a network of telescopes that scans the entire sky multiple times each night looking for moving objects that might pose a threat to Earth. Within hours, astronomers around the world were thrilled by the discovery: the object appeared to be the third-known interstellar object to pass through our solar system, behind 1I/'Oumuamua in 2017 and 2I/Borisov in 2019.
