For only the third time in recorded history, astronomers have identified an interstellar object passing through our solar system—and this one’s putting on quite a show. On July 1, 2025, the Asteroid Terrestrial-impact Last Alert System (ATLAS) picked up a faint but distinct cosmic visitor now officially named comet 3I/ATLAS. Using the Gemini North telescope atop Maunakea in Hawaii, scientists have snapped some of the most detailed images yet of this rare wanderer, revealing its compact coma—a fuzzy cloud of ice and dust surrounding its nucleus.
Currently, 3I/ATLAS is about 290 million miles from Earth and will come no closer than roughly 170 million miles on December 19, so there’s zero risk to our planet. Still, astronomers around the world are racing to study it before it fades back into the blackness of interstellar space. What makes this find especially exciting is its orbit: with an eccentricity of 6.2 (where zero is perfectly circular), 3I/ATLAS has all the hallmarks of an object that originated outside our solar system and will never return.
Size estimates put this ancient traveler somewhere between one and two kilometers across, according to John Noonan at Auburn University—making it comparable to previous interstellar guests like 2I/Borisov (about one kilometer wide) and larger than the famous ʻOumuamua (roughly 400 meters long). But what’s truly captivating scientists is how different 3I/ATLAS appears compared to any comet seen before. Early analyses suggest it’s older than our solar system itself, and its surface may hold clues to galactic processes far beyond our neighborhood.
With only two other interstellar objects ever confirmed—ʻOumuamua in 2017 and Borisov in 2019—the discovery of another so soon hints we might be on the brink of spotting many more. New survey telescopes like the Vera C. Rubin Observatory are coming online soon, promising to catch even more cosmic hitchhikers as they cruise through our neck of the galaxy.
As for now, astronomers are urging skywatchers to keep an eye out for new images in the coming months, as comet 3I/ATLAS makes its brief but spectacular pit stop before being lost to interstellar space once again.
