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JWST Finds 10-Billion-Year-Old Interstellar Comet with 30× Deuterium

6/24/2026

Summary

Scientists Discover Ancient

U.S. scientists used the James Webb Space Telescope to observe interstellar comet 3I/ATLAS in December 2025.
NIRSpec recorded its spectrum, showing deuterium about thirty times higher than in Solar System comets.
The spectrum also revealed only trace carbon-13 versus carbon-12, implying formation before galactic carbon-13 enrichment.
Researchers dated the comet to 10–12 billion years old, older than the Sun, and reported the results in Nature on 22 June 2026.

Summary

NASA Confirms Interstellar

NASA confirmed 3I/Atlas is on an outbound trajectory that will leave the solar system forever.
Hubble images on Nov. 30 2025 showed a bright tail at 180 million miles, prompting expectations that the Vera C. Rubin Observatory will detect dozens of new interstellar objects.
NASA dismissed Harvard astronomer Avi Loeb’s alien-origin claims after SETI found no evidence of extraterrestrial technology, while scientists warned the comet’s fading brightness will soon limit observations.

History

Historical Context

Pan-STARRS’s 2017 detection of 1I/‘Oumuamua proved that interstellar bodies cross Earth’s orbit, and models now predict about 10,000 such objects inside Neptune’s orbit at any moment. The 2025 discovery of comet 3I/Atlas by the James Webb Space Telescope and Hubble confirmed the pattern, prompting NASA and the Vera C. Rubin Observatory to institutionalize interstellar-object monitoring.

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Scientists Discover Ancient

U.S. scientists used the James Webb Space Telescope to observe interstellar comet 3I/ATLAS in December 2025.
NIRSpec recorded its spectrum, showing deuterium about thirty times higher than in Solar System comets.
The spectrum also revealed only trace carbon-13 versus carbon-12, implying formation before galactic carbon-13 enrichment.
Researchers dated the comet to 10–12 billion years old, older than the Sun, and reported the results in Nature on 22 June 2026.

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