First water in the universe emerged from ancient exploding stars, new study shows

Water appears to have emerged far earlier than once thought—less than 200 million years after the Big Bang—according to research in Nature Astronomy. Using advanced 3D simulations, scientists discovered that the first supernovae produced oxygen, which rapidly bonded with hydrogen to form water, permeating early galaxies. “Besides revealing that a primary ingredient for life was already in place in the Universe 100–200 million years after the Big Bang, our simulations show that water was probably a key constituent of the first galaxies,” the authors wrote.

This finding challenges assumptions about when and how water took shape, suggesting conditions suitable for life arose surprisingly early. By tracking how these primordial explosions enriched their surroundings with oxygen, the team found that H₂O likely became a core part of the dense gas clouds that would later give rise to stars and planets.

The key finding is that primordial supernovae formed water in the Universe that predated the first galaxies.

Led by astrophysicist Daniel Whalen, Ph.D., of the University of Portsmouth’s Institute of Cosmology and Gravitation, and in collaboration with the United Arab Emirates University, the study shows how these stellar explosions served as cosmic gardeners, sowing water in primordial star-forming regions. “Before the first stars exploded, there was no water in the Universe because there was no oxygen,” Whalen explained in a press release. This means life’s essential ingredient has been around almost since the universe’s dawn, reshaping our timeline for cosmic habitability.