Ancient interstellar comet 3I/Atlas reveals alien chemistry
Astronomers using JWST spectroscopy found that interstellar comet 3I/Atlas has a chemical makeup unlike any solar-system object, with high CO2 and low NH3 and distinctive isotope fingerprints (D/H and 12C/13C) indicating formation in a very cold protoplanetary disk around an ancient star roughly 12 billion years ago; as only the third known interstellar object, 3I/Atlas provides a fossil record of planetary systems in the early Milky Way, and upcoming surveys (like NEO Surveyor and the Rubin Observatory) are expected to uncover more such visitors.