Anonymous22 days ago
Interstellar comet 3I/ATLAS, discovered in July 2025 and now the most thoroughly characterized interstellar object in history, has revealed a chemical composition unlike anything in our solar system — including extreme deuterium enrichment, anomalous carbon isotope ratios dating its formation to 10–12 billion years ago, record-breaking methanol abundance, and a near-total absence of ammonia. The findings, drawn from JWST, ALMA, and over a dozen other telescopes, suggest the comet formed in a cold, metal-poor protoplanetary disk during the Milky Way's early history, offering scientists an unprecedented frozen archive of extrasolar planetary chemistry.