Astronomers have detected the third-ever confirmed interstellar object, comet 3I/Atlas, within our solar system. Discovered on July 1, 2025, by the ATLAS survey telescope in Chile, this comet offers a rare opportunity to study material from another star system and potentially understand the early Milky Way.

The interstellar comet 3I/Atlas was identified by its steep orbit and high speed, confirming its origin outside our solar system. Sarah Greenstreet, an astronomer at the University of Washington, notes, “Astronomers around the world will be pointing their telescopes, large and small, at this object… providing us with clues about its home planetary system.” Preliminary analysis suggests the comet may originate from the thick disk of the Milky Way, a region populated by some of the galaxy's oldest stars, potentially making it up to 7 billion years old – significantly older than our solar system. Scientists will study 3I/Atlas over the coming months to learn more about its composition and origin. The study of interstellar objects like ‘Oumuamua and 2I/Borisov provides valuable insights into the diversity of planetary systems beyond our own and helps refine our understanding of the galaxy's history and composition.