Astronomers Discover Third Interstellar Object Speeding Through Solar System
HONOLULU, Hawaii — For the third time in history, astronomers have confirmed the discovery of an interstellar object traveling through our solar system. The newly named 3I/ATLAS, likely a comet, is estimated to be as large as 12 miles (20 kilometers) in diameter and is speeding toward the sun at approximately 68 kilometers per second, or about 152,000 miles per hour.
The Minor Planet Center (MPC) officially designated the object on July 2, 2025. Its name includes an ‘I’ to signify its interstellar origin. According to the MPC, there are tentative reports of cometary activity, with evidence suggesting a marginal coma and a short tail.
John Tonry, an astronomer at the University of Hawaii, remarked, “These interstellar visitors provide an extremely interesting glimpse of things from solar systems other than our own.” This object is notable for being the largest interstellar object detected so far, following ‘Oumuamua in 2017 and comet 2I/Borisov in 2019.
On July 1, the object was added to the Near-Earth Object confirmation list. It is currently moving through the Milky Way, making it challenging to observe among countless stars. However, researchers report it poses no risk to Earth.
The object will reach its closest point to the sun in October, about twice the distance of Earth from the sun, and will pass within 0.4 AU of Mars. While it currently shines at a dim magnitude of around 17.5, experts believe it will brighten, potentially reaching magnitude 16 by August, allowing more observers to capture images.
“Although Comet 3I/ATLAS is currently dim, advanced amateur astronomers may be able to photograph it using long exposure through a telescope,” said Eddie Irizarry, who has been mapping its trajectory. “Next April, it will have a velocity relative to Earth of about 90 kilometers per second.”
This discovery has excited the scientific community, with ongoing observations planned using various telescopes around the world. The International Astronomical Union’s Minor Planet Center adds that this object provides a rare opportunity to study materials from beyond our solar system.
