• Interstellar comet 3I/ATLAS preserves a chemical record from the Milky Way’s earliest planetary systems

    ByReet Kaur

    The interstellar comet 3I/ATLAS formed in an exceptionally cold, relatively metal-poor stellar nursery as long as 10 to 12 billion years ago, according to observations by NASA’s James Webb Space Telescope and a study published in Nature on June 22, 2026. Measurements of unusually high deuterium in water and exceptionally low abundances of carbon-13 compared to carbon-12 distinguish the object from every comet measured in the Solar System, providing a rare glimpse into the chemistry of one of the Galaxy’s earliest planetary systems.

  • Interstellar comet 3I/ATLAS may be a fragment of a 12-billion-year-old planetary system

    ByReet Kaur

    The third confirmed interstellar object detected in the Solar System possesses an isotopic composition unlike any known Solar System comet, according to a study published in Nature on June 22, 2026. Observations with the James Webb Space Telescope revealed extreme enrichments in heavy hydrogen and unusual carbon isotope ratios, leading researchers to conclude that 3I/ATLAS likely formed in a cold, metal-poor environment during an early phase of Milky Way evolution, potentially 10 to 12 billion years ago.

  • Extreme isotopic signatures in 3I/ATLAS point to origin in the early Milky Way

    ByTeo Blašković

    Extreme deuterium enrichment measured in both water and methane in the interstellar object 3I/ATLAS suggests formation in a very cold environment (≲30 K) and possibly early in the history of the Milky Way, according to two preprint studies based on James Webb Space Telescope observations conducted on December 22 and 23, 2025. The isotopic compositions differ sharply from those measured in known Solar System comets and point to formation in an environment chemically distinct from that of the Solar System.

  • Interstellar object 3I/ATLAS becomes a fully active comet after perihelion

    ByReet Kaur

    NASA’s SPHEREx space telescope re-observed the interstellar object 3I/ATLAS in December 2025 and detected a dramatic increase in activity after perihelion, including strong water outgassing, multiple new gas species, and a transition from icy grains to refractory dust in its coma.

  • NASA missions capture multi-platform views of interstellar comet 3I/ATLAS

    ByReet Kaur

    NASA spacecraft positioned from Mars orbit to near-Sun vantage points have collected coordinated observations of interstellar comet 3I/ATLAS, forming a solar system–wide dataset as the object travels inward ahead of its December 19, 2025 closest approach to Earth.

  • Discovery of water in 3I/ATLAS reveals chemistry shared across the galaxy

    ByReet Kaur

    A team of Auburn University physicists using NASA’s Neil Gehrels Swift Observatory has detected water’s ultraviolet fingerprint in interstellar comet 3I/ATLAS. The discovery, published on September 30, 2025, in The Astrophysical Journal Letters, marks the first confirmed ultraviolet detection of water from a comet that originated beyond our solar system.

  • ESA’s Mars orbiters record interstellar comet 3I/ATLAS in once-in-a-lifetime encounter

    ByReet Kaur

    The European Space Agency’s (ESA) ExoMars Trace Gas Orbiter (TGO) and Mars Express spacecraft recorded images of interstellar comet 3I/ATLAS on October 3, 2025, from about 30 million km (18.6 million miles) away, marking the closest observation of the object from any spacecraft so far.