Interstellar Comet 3I/ATLAS Displays Stunning Jet Eruptions During December Earth Flyby
Interstellar comet 3I/ATLAS provided astronomers with a rare glimpse of material from another star system during its closest Earth approach in December 2025. Discovered on July 1 by Chile's Asteroid Terrestrial-impact Last Alert System (ATLAS), the object zipped past at 270 million kilometers on December 19, clocking 58 kilometers per second—the fastest interstellar visitor on record.
Hubble Space Telescope images from December 12 and 27 captured twin jets blasting from the nucleus, maintaining remarkable alignment and persistence unlike typical cometary outbursts. Per International Business Times UK, this structured activity defies standard models, where outgassing usually disperses quickly into chaotic plumes.
Pivotal Search for Extraterrestrial Tech
One day prior, the Breakthrough Listen initiative ran history's most sensitive radio sweep using the 100-meter Green Bank Telescope across 1-12 GHz bands on December 18. No artificial signals emerged down to 0.1-watt sensitivity—equivalent to a tenth of a cellphone's output. Over 471,000 candidates were vetted and dismissed as Earth-based interference.
Water Traces Confirm Natural Makeup
The Solar and Heliosphere Observatory spotted prolific water vapor in early November, peaking at 3.17 × 10²⁹ molecules per second on November 6—enough to fill an Olympic pool every few seconds post-perihelion on October 30. Rates dropped to 10-20 quintillion trillion by December, mirroring Solar System norms.
Rich in carbon dioxide with a sunward "anti-tail" jet, 3I/ATLAS—potentially 7-13 billion years old—likely hails from the Milky Way's crowded core. It will graze Jupiter in March 2026 before departing forever, visible in Cancer through late January while yielding invaluable insights into distant worlds.
