Astronomers discover oldest known comet, 3I/ATLAS
A comet called 3I/ATLAS, discovered by the ATLAS survey telescope on July 1, 2025, is cruising through our solar system—and it's a true cosmic elder at about seven billion years old (yep, older than the Sun).
This is only the third time scientists have confirmed an object from another star system visiting us.
A glimpse of the comet's journey
3I/ATLAS likely formed among ancient stars in a part of the Milky Way we've never sampled before. It was first spotted far from the Sun.
The comet will swing closest to the Sun just inside Mars's orbit—expect a bright coma and tail as its icy insides heat up.
Bigger than previous interstellar visitors
Early observations suggest this comet is bigger than previous interstellar visitors.
Telescopes like the Vera C. Rubin Observatory are tracking it before sunlight makes it hard to see.
Its discovery hints that many more cosmic guests could show up soon—so space science just got a lot more interesting!