Interstellar comet 3I/ATLAS origin and chemistry

Developing StoryLast updated
SUMMARY

Astronomers using the James Webb Space Telescope determined on July 17, 2026, that interstellar comet 3I/ATLAS is chemically distinct from Solar System comets, suggesting it is billions of years older and originated from a primitive, cold environment. As of July 17, 2026, its unusual isotopic ratios of carbon and high deuterium enrichment in water indicate formation in an early epoch of galactic history, predating our Solar System. The object's name is linked to the Asteroid Terrestrial-impact Last Alert System (ATLAS), which became fully operational in 2017.

Timeline

Want updates on this thread?

Track this story

July 2026 — 2 developments

  1. JWST Reveals Interstellar Comet 3I/ATLAS is Billions of Years Older Than Solar System

    Astronomers using the James Webb Space Telescope have determined that interstellar comet 3I/ATLAS is chemically distinct from Solar System comets, suggesting it is billions of years older and originated from a primitive, cold environment. Its unusual isotopic ratios of carbon and high deuterium enrichment in water indicate formation in an early epoch of galactic history, predating our Solar System.

  2. Hypothetical Interstellar Object 3I/ATLAS Proposed as Future Candidate

    The concept of 3I/ATLAS was proposed as a hypothetical interstellar object, envisioned as a candidate for the third interstellar object to be detected in our solar system. Its existence is based on theoretical models and simulations, rather than direct observation. The object's name is directly linked to the operational ATLAS survey system, which has the capability to potentially detect such celestial bodies.

January 2017 — 1 developments

  1. ATLAS Robotic Astronomical Survey System Becomes Fully Operational

    The Asteroid Terrestrial-impact Last Alert System (ATLAS), a robotic astronomical survey system, became fully operational in 2017. Developed by the University of Hawaii and funded by NASA, ATLAS is designed to detect objects that could potentially impact Earth. This system is also capable of detecting interstellar objects, and its name serves as the namesake for the hypothetical 3I/ATLAS.