NASA’s James Webb Space Telescope (JWST) has captured detailed measurements of the chemical composition of interstellar comet 3I/ATLAS. The observations were made in December 2025, as the comet was moving away from the Sun after its closest approach, an optimal time to study the volatile material released by solar heating. This comet, the second interstellar object detected in our solar system, offers a unique opportunity to analyze pristine material from another star system.

JWST’s spectroscopic analysis allowed for the identification of 3I/ATLAS’s chemical components, providing clues about its formation conditions and the environment of its home star system. Webb’s ability to detect molecules in the comet’s coma, even at great distances and low luminosity, is crucial for these types of studies. These data are fundamental for comparing the chemistry of interstellar objects with that of comets in our own solar system, which can shed light on the diversity of planetary formation processes across the Milky Way.