- The interstellar comet 3I/ATLAS is extremely old—about 10–12 billion years—making it likely the oldest object ever seen pass through our solar system.
- Its chemistry is unlike anything here: it formed in a much colder place, its water has roughly 30× more deuterium than solar system comets, and it carries abundant organic molecules.
- Studied with the James Webb Space Telescope, 3I/ATLAS is the third known interstellar visitor (after ’Oumuamua and Borisov), is a natural comet, and will exit the solar system around the mid-2030s.
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