James Webb Space Telescope Reveals Interstellar Comet 3I/ATLAS Predates the Sun with Unusual Methane Composition

Observations from the James Webb Space Telescope (JWST) indicate that the interstellar comet 3I/ATLAS may have formed more than 7 billion years before our Sun. Scientists were particularly surprised by its methane's deuterium-to-hydrogen ratio, which is 13 times higher than that of comet 67P/Churyumov-Gerasimenko, suggesting a primordial formation, low metallicity, and high cosmic ray exposure. The findings also shed light on the unique water-ice grains of this object, providing a rare glimpse into the icy building blocks of other star systems.