The discovery of ancient water in a planet-forming disk reveals that some of the water found in comets—and maybe even Earth—is older than the disk’s star itself, offering breakthrough insights into the history of water in our solar system.
Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have made a first-ever detection of doubly deuterated water (D₂O, or “heavy water”) in a planet-forming disk around V883 Ori, a young star. This means that the water in this disk, and by extension the water in comets that form here, predates the birth of the star itself, having journeyed through space from ancient molecular clouds long before this solar system formed.
The research is published in the journal Nature Astronomy.









