We Were Wrong About Where 3I/ATLAS Comes From
For a year, the story was simple: interstellar comet 3I/ATLAS is older than the Sun. Then astronomers read its ice, and both the number and what that number actually measures changed.
This video covers active, unsettled science. The ages here are best estimates from current measurements, not settled fact.
Here's what you get: why the original "seven billion years" came from the comet's orbit and was never proof; how deuterium (heavy water) and carbon-13 work as two independent clocks that agree; why James Webb and ALMA landed on the same reading; the honest catch almost no coverage mentions, that we may be dating the radiation-beaten crust and not the core; and what an object older than the Sun says about whether the ingredients for life are common. If you have ever searched how old 3I/ATLAS really is, this is the full answer, sourced to the papers below.
Sourcing note: every figure here is pulled from the named primary papers listed below, not from secondary coverage. If a claim wasn't in a primary source, it didn't make the script.
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SOURCES & FURTHER READING
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"The orbital age placing 3I/ATLAS in the galaxy's thick disk", Hopkins et al., 2025 — https://arxiv.org/abs/2507.05318
"An independent kinematic age for the interstellar comet", Taylor & Seligman, 2025 — https://arxiv.org/abs/2507.08111
"First measurement of heavy water (deuterium) in an interstellar object", Salazar Manzano & Paneque-Carreño (ALMA), 2026 — https://www.almaobservatory.org/en/press-releases/alma-reveals-interstellar-comet-3i-atlas-formed-in-a-far-colder-world-than-our-own/
"Isotopic evidence for a cold, distant origin and a 10 to 12 billion year age", Cordiner et al. (JWST), 2026 — https://esawebb.org/news/weic2613/
"The record carbon-dioxide reading in the coma, JWST NIRSpec", Cordiner et al., 2025 — https://arxiv.org/abs/2508.18209
"Post-perihelion composition shift, hinting at a crust unlike the core", Shinnaka et al. (Subaru), 2026 — https://subarutelescope.org/en/results/2026/04/14/3701.html
"What interstellar samples tell us about the conditions for life", Milam, NASA Goddard, 2026 — https://science.nasa.gov/missions/webb/nasas-webb-finds-clues-to-ancient-distant-origin-of-comet-3i-atlas/
Image: NASA/ESA/CSA (James Webb) · ESO/NAOJ/NRAO (ALMA) · NAOJ (Subaru Telescope)
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CONTINUE THE DISCUSSION
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What should we cover next?
#spacialize #3IAtlas #JamesWebb