New analysis of ALMA observations of interstellar comet 3I/ATLAS show its water carries a chemical signature pointing to a colder, more distant origin than any comet ever measured. Water sampled from 3I/ATLAS (left) has 30 times the concentration of deuterated water molecules that Earth’s oceans do (right), as shown in this illustrated comparison. Credit: NSF/AUI/NSF NRAO/M. Weiss We already knew interstellar comet 3I/ATLAS came from somewhere far beyond our solar system. Now scientists have more information on how alien that somewhere really is — a corner of the universe colder than, less irradiated than, and chemically distinct from the conditions that shaped our home. A study published April 23 in Nature Astronomy reveals that 3I/ATLAS carries water with an extraordinary concentration of what’s known as deuterated water. The finding marks the first time scientists have ever measured deuterated water in an interstellar object — and the numbers are unlike anything we’ve seen before.…