Discovered July 1, 2025, Passed The Sun At 1.5 AU In October, Now Past Jupiter And Leaving Forever; JWST’s MIRI Instrument Has Produced The First Mid-Infrared Chemical Fingerprint Ever Obtained From A Visitor Between The Stars
According to NASA Science, the New York Post, and the Astrophysical Journal Letters, NASA’s James Webb Space Telescope has produced the first mid-infrared chemical fingerprint ever obtained from an interstellar object, detecting methane, carbon dioxide, and water vapour in comet 3I/Atlas’s coma during two observations in December 2025. The findings were led by Caltech graduate student Matthew Belyakov and published on April 8, 2026.
3I/Atlas is only the third confirmed object to originate from outside our solar system. Discovered July 1, 2025, by the NASA-funded ATLAS survey telescope in Chile, it looped around the sun within 1.5 astronomical units in October 2025 and is now past Jupiter, leaving the solar system forever.
For the first time on any interstellar visitor, JWST directly detected methane gas. Methane is highly volatile; its delayed appearance in 3I/Atlas’s coma suggests it was buried below the surface, only sublimating as solar heating penetrated deeper into the nucleus.
Harvard’s Professor Avi Loeb; who has previously catalogued 22 anomalies in 3I/Atlas’s behaviour says the methane detection adds further questions that natural comet science has not yet fully answered. Most researchers believe the object is an unusually composition-rich natural comet from a colder, more distant stellar system. Loeb maintains that all possibilities should remain on the table.
To check out our previous coverage on 3I/Atlas and space science, read our articles here.
