Interstellar comet 3I/ATLAS contains strange water never seen in our solar system

A mysterious comet from beyond our solar system is giving astronomers a rare glimpse into alien worlds — and it may have formed in a place far colder and stranger than anything around our Sun. The interstellar visitor, called 3I/ATLAS, contains an astonishingly high amount of “heavy water,” far exceeding anything seen in our own solar system.