I/ATLAS isn't just fascinating because it is the third interstellar visitor found in the solar system; new research suggests it's also the oldest comet ever seen, at over 7 billion years old.

When the news started to spread on July 1, 2025, about a new object that was spotted from outside our solar system, only the third of its kind ever known, astronomers at Michigan State University—along with a team of international researchers—turned their telescopes to capture data on the new celestial sighting.

The solar system has an uninvited guest that is currently shooting toward us on a one-way trip through our cosmic neighborhood.The newly discovered interstellar visitor, named 3I/ATLAS, is only the third of its kind ever seen.