NASA’s SPHEREx mission has made a groundbreaking discovery in one of the Milky Way’s most active star-forming regions, Cygnus X. Using its advanced infrared capabilities, SPHEREx has mapped water ice in unprecedented detail. The Cygnus X region, located about 4,500 light-years away, is known for its dense clouds of dust and gas, which are the birthplaces of new stars.
According to NASA, this area is a prime location to study how various molecules, including water ice, are distributed and protected from intense radiation. The findings, published in The Astrophysical Journal on April 15, 2026, reveal that water ice molecules are shielded by dust particles no larger than those found in candle smoke
SPHEREx Maps Water Ice Across the Sky
SPHEREx, short for Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer, launched in March 2025. This mission is the first of its kind to conduct an infrared survey of the entire sky, capturing data in 102 different wavelengths of light.
As reported by the NASA, The Cygnus X region, located about 4,500 light-years away, is known for its dense clouds of dust and gas, which are the birthplaces of new stars. This area is a prime location to study how various molecules, including water ice, are distributed and protected from intense radiation.
“We expected to detect these ices in front of individual bright stars: The light from a star acts like a spotlight, revealing any ice in the space between us and that star. But this is something different,” as noted by lead researcher Joseph Hora, an astronomer at the Center for Astrophysics at Harvard & Smithsonian in Cambridge. “When looking along the galactic plane — where most of the stars, gas, and dust of our galaxy are concentrated — there’s a lot of diffuse background light shining through entire dust clouds, and SPHEREx can see the spatial distribution of the ices they contain in incredible detail.”
NASA’s SPHEREx mission reveals vast frozen regions in Cygnus X, with bright blue water ice perfectly aligned with dark interstellar dust lanes. Credit: NASA
The findings reveal that water ice molecules are shielded by dust particles no larger than those found in candle smoke. The water ice observed in Cygnus X appears in bright blue on SPHEREx images, clearly distinguishable from other compounds like polycyclic aromatic hydrocarbons, which appear in orange.
Dust Shields the Ice from Radiation
One of the most significant discoveries made by SPHEREx is the relationship between water ice and dust particles in space. As explained by the researchers involved in the study:
“The findings show the densest regions of ice coincide with the densest regions of dust, and the dust shields the ice from the intense ultraviolet radiation emitted by newborn stars.”
NASA’s SPHEREx mission highlights the interstellar dust in the Cygnus X star-forming region. Credit: NASA
The dust acts as a shield, allowing the ice to survive in regions that would otherwise be too hostile for such molecules. The study supports a long-standing hypothesis that ice forms on the surface of dust particles, with these tiny grains acting as a protective layer against the harsh conditions of space.
“We can investigate the environmental factors that contribute to different ice formation rates across large areas of interstellar space,” said Gary Melnick, a study coauthor and astronomer at the CfA. “The SPHEREx mission’s ‘big picture’ view provides valuable new information you can’t get when zooming in on a small region.”