NASA’s SPHEREx Mission Maps Water Ice Across the Galaxy, Revealing Abundant Life-Essential Molecule in Space

NASA’s SPHEREx mission has mapped water ice across vast regions of the Milky Way galaxy, confirming that an essential molecule for life on Earth is abundant in space and originates in stellar nurseries where new solar systems form.

The observations, made by the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx), reveal frozen complexes of water ice spanning more than 600 light-years across in the Cygnus X star-forming region. These interstellar ices are found inside giant molecular clouds, where dense clumps of gas and dust collapse under gravity to form new stars.

Water ice, carbon dioxide, and carbon monoxide ices are attached to the surfaces of tiny dust particles no larger than those found in candle smoke. The study, published April 15, 2026, in The Astrophysical Journal, shows that the densest regions of ice coincide with the densest regions of dust, which shields the ice from intense ultraviolet radiation emitted by newborn stars.

These frozen reservoirs are where most of the universe’s water is formed and stored. The water in Earth’s oceans, as well as the ices in comets and on other planets and moons in our galaxy, originates from these interstellar ice formations.

Phil Korngut, instrument scientist for SPHEREx at Caltech in Pasadena, California, described these vast frozen complexes as “interstellar glaciers” that could deliver a massive water supply to new solar systems forming in the region. He noted that it is profound to observe material that could rain on nascent planets and potentially support future life.

The findings support the hypothesis that interstellar ice forms on the surface of tiny dust particles. By mapping the chemical signatures of water ice and other molecules, SPHEREx is helping scientists understand the origins of water and the prebiotic chemistry that may lead to life elsewhere in the galaxy.

This research provides critical context for understanding how water—a fundamental requirement for life as we know it—is distributed throughout the universe and incorporated into forming planetary systems. While the presence of water ice in space does not guarantee life, it confirms that one of the key ingredients for life is widespread in the Milky Way.