Astronomers have made a stunning discovery that reveals just how ancient some of the water in our universe really is. Using the powerful Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, scientists detected a rare type of water—called “heavy water”—in a planet-forming disk around a young star named V883 Orionis.
This marks the first-ever detection of heavy water (D₂O) in a disk where planets are taking shape. Heavy water is like regular water (H₂O), but with a twist: it contains a heavier version of hydrogen called deuterium. The ratio of deuterium to hydrogen acts as a kind of chemical fingerprint, allowing scientists to trace the age and origin of water molecules.
In this case, the fingerprint showed that the water in V883 Orionis’s disk existed long before the star itself was born.
“Our detection proves that the water we see in this planet-forming disk must be older than the star,” said lead author Margot Leemker, a physicist at the University of Milan. “It formed during the earliest stages of star and planet formation, which means we’re seeing truly ancient water.”
This discovery offers a major clue about how water travels through space. It suggests that some of the water found in comets—and possibly even the water on Earth—did not form in young solar systems, but instead dates back to ancient clouds of gas and dust that existed before the Sun was born. In other words, the water in your morning coffee might be older than the Sun itself.
John Tobin, a co-author from the U.S. National Science Foundation’s National Radio Astronomy Observatory, explained that until now, astronomers weren’t sure whether most water in planets and comets formed fresh in young disks or was inherited from earlier cosmic stages.
“This finding shows that much of the water we see in planetary systems is pristine—it’s a hand-me-down from interstellar space,” Tobin said.
By measuring the ratio of heavy water (D₂O) to normal water (H₂O), the researchers confirmed that this water came directly from ancient molecular clouds. This is the first solid evidence showing that water can survive the violent process of star and planet formation without being destroyed or remade.
The discovery helps piece together a cosmic puzzle linking interstellar clouds, planet-forming disks, comets, and planets. Since water is essential for life, understanding its origins can reveal more about how habitable worlds like Earth come to be.
If water can survive across billions of years and countless light-years, it’s likely that many young planets throughout the universe are also born with ancient water—connecting life on Earth to the universe’s distant past.
https://knowridge.com/2025/10/water-in-your-coffee-might-be-older-than-the-sun-study-finds/