CAPE CANAVERAL, FLORIDA – A comet from beyond our solar system is making a fleeting visit to Earth this week before continuing its journey back into interstellar space.
Discovered over the summer, the object—designated 3I/Atlas—will pass within 167 million miles (269 million kilometers) of Earth on Friday, marking its closest approach during its sweep through the solar system. NASA is keeping its space telescopes trained on the icy visitor, which measures between roughly 1,444 feet (440 meters) and 3.5 miles (5.6 kilometers) across. As it moves away and fades, amateur astronomers with backyard telescopes have a prime opportunity to observe it.
Later in its trajectory, 3I/Atlas will pass about 33 million miles (53 million kilometers) from Jupiter in March. Scientists say it will take until the mid-2030s for the comet to fully leave the solar system, never to return.
This is only the third interstellar object detected passing through our solar system. Unlike familiar comets from the outer reaches of our own system, interstellar comets like 3I/Atlas come from star systems elsewhere in the Milky Way. The first confirmed interstellar visitor was spotted in 2017, followed by a second discovery two years later by an amateur astronomer in Crimea. NASA’s ATLAS telescope in Chile discovered 3I/Atlas in July while scanning for potentially hazardous asteroids.
Researchers note that this comet may have originated in a star system much older than our own, making it a particularly intriguing target for study despite posing no threat to Earth.