‘Interstellar Glaciers’: NASA’s SPHEREx Maps Vast Galactic Ice Regions

These observations made by NASA’s SPHEREx mission reveal vast frozen complexes in the Cygnus X star-forming region of the Milky Way galaxy. Water ice, shown as bright blue structures at left, exactly overlays the dark lanes of interstellar dust, shown in different wavelengths at right. Credit: NASA/JPL-Caltech/IPAC/Hora et al. Full Image Details

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The water, carbon dioxide, and carbon monoxide ices are attached to the surface of tiny dust particles in clouds spanning hundreds of light-years across.

NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) mission has mapped interstellar ice at an unprecedented scale. Covering regions in our Milky Way galaxy more than 600 light-years across, the ice was found inside giant molecular clouds — vast regions of gas and dust where dense clumps of matter collapse under gravity, giving birth to stars. A study describing these findings published Wednesday in The Astrophysical Journal.

One of SPHEREx’s main goals is to map the chemical signatures of various types of interstellar ice. This ice includes molecules like water, carbon dioxide, and carbon monoxide, which are vital to the chemistry that allows life to develop. Researchers believe these ice reservoirs, attached to the surfaces of tiny dust grains, are where most of the universe’s water is formed and stored. The water in Earth’s oceans — and the ices in comets and on other planets and moons in our galaxy — originates from these regions.

“These vast frozen complexes are like ‘interstellar glaciers’ that could deliver a massive water supply to new solar systems that will be born in the region,” said study coauthor Phil Korngut, the instrument scientist for SPHEREx at Caltech in Pasadena, California. “It’s a profound idea that we are looking at a map of material that could rain on nascent planets and potentially support future life.”

Thanks to its spectral capabilities, SPHEREx can measure the amounts of various ices and molecules, such as polycyclic aromatic hydrocarbons, in and around molecular clouds, helping scientists better understand their composition and environment.

Although space telescopes such as NASA’s James Webb Space Telescope and the agency’s retired Spitzer have detected water, carbon dioxide, carbon monoxide, and other icy molecules throughout our galaxy, the SPHEREx observatory is the first infrared mission specifically designed to find such molecules over the entire sky via the mission’s large-scale spectral survey.

“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,” said lead author Joseph Hora, an astronomer at the Center for Astrophysics (CfA) at Harvard & Smithsonian in Cambridge, Massachusetts. “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.”

Managed by NASA’s Jet Propulsion Laboratory in Southern California, the SPHEREx observatory launched March 11, 2025, and has the unique ability to see the sky in 102 colors, each representing a different wavelength of infrared light that offers distinctive information about galaxies, stars, planet-forming regions, and other cosmic features. By late 2025, SPHEREx had completed the first of four all-sky infrared maps of the universe, charting the positions of hundreds of millions of galaxies in 3D to help answer major questions about the cosmos, including those about the origins of water and life.

Icy origins

Using the SPHEREx maps of various icy molecules, the study’s authors were able to look deep into many molecular clouds in the Cygnus X and North American Nebula regions of the Milky Way. In the densest areas, where the amount of dust is greatest, dark filamentary lanes block the visible light from the stars behind. With its infrared eye, the space telescope also revealed where the different ices — which absorb specific wavelengths of infrared light that would pass through the clouds if they consisted only of dust — are at their densest.

This finding supports the hypothesis that interstellar ice forms on the surface of tiny dust particles, which are no larger than particles found in candle smoke, and that the dense regions of dust shield the ices from the intense ultraviolet radiation emitted by newborn stars. However, not all ices are treated the same way in the interstellar medium.

“We can investigate the environmental factors that contribute to different ice formation rates across large areas of interstellar space,” said study coauthor Gary Melnick, also an 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.”

Within this broad perspective, adds Melnick, SPHEREx can do something ground-based observatories cannot: detect varying amounts of water and carbon dioxide, two ices that respond differently to environmental factors. For example, the presence of intense ultraviolet light from nearby massive young stars or the heating of these dust grains by that light affects the abundances of different ices in distinct ways.

This is just the beginning for the mission. Observations from SPHEREx will provide scientists with a powerful tool to explore the various components of our galaxy, the physics of the interstellar medium that lead to star and planet formation, and the chemical processes that deliver molecules essential for life to newly formed planets. More about SPHEREx

More about SPHEREx

The mission is managed by JPL for the agency’s Astrophysics Division within the Science Mission Directorate in Washington. The telescope and the spacecraft bus were built by BAE Systems in Boulder, Colorado. The science analysis of the SPHEREx data is being conducted by a team of scientists at 13 institutions across the U.S. and in South Korea and Taiwan, led by Principal Investigator Jamie Bock, who is based at Caltech with a joint JPL appointment, and by JPL Project Scientist Olivier Doré. Data is processed and archived at IPAC at Caltech in Pasadena, which manages JPL for NASA. The SPHEREx dataset is freely available to scientists and the public.

For more information about the SPHEREx mission visit: https://science.nasa.gov/mission/spherex/

Source: JPL-Caltech/Stars and Galaxies

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Astronomers Map Mysterious “Dark” Gas in the Milky Way

This collection of images shows the location of the CO-dark molecular gas in the constellation Cygnus X, and NSF Green Bank Telescope data of the gas in the galactic latitude and longitude.Credit: NSF/AUI/NSF NRAO/P.Vosteen

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New research exposes CO-dark molecular gas, previously invisible to telescopes, uncovering the hidden building blocks of our Galaxy

An international team of astronomers has created the first-ever large-scale maps of a mysterious form of matter, known as CO-dark molecular gas, in one of our Milky Way Galaxy’s most active star-forming neighborhoods, Cygnus X. Their findings, using the U.S. National Science Foundation’s Green Bank Telescope (NSF GBT), are providing crucial new clues about how stars formed in the Milky Way.

For decades, scientists have known that most new stars are born inside clouds of cold molecular hydrogen gas. Much of this molecular hydrogen is invisible to most telescopes—it doesn’t give off light that can easily be detected. Traditionally, astronomers have hunted for these clouds by looking for carbon monoxide (CO), a molecule that acts like a flashing sign for star-building regions. However, it turns out there’s a lot of star-forming gas that doesn’t “light up” in CO. This dark, hidden material (called CO-dark molecular gas) has been one of astronomy’s biggest blind spots.

Now, for the first time, astronomers have mapped this hidden gas over a huge swath of sky—more than 100 times the area covered by the full Moon—by observing the radio spectral lines from atoms recombining, known as Carbon Radio Recombination Lines (CRRLs). The team’s map covers the bustling Cygnus X region, a cosmic metropolis about 5,000 light-years away, that’s overflowing with newborn stars.

“It’s like suddenly turning on the lights in a room and seeing all sorts of structures we never knew were there,” says Kimberly Emig, an associate scientist with the NSF National Radio Astronomy Observatory (NSF NRAO), and lead author of the new study.

The new map reveals a vast network of arcs, ridges, and webs of dark gas weaving through Cygnus X. These shapes show where star-making material is gathered and grown, before it becomes visible as before it becomes visible in CO as molecular clouds. The research demonstrates that these faint carbon signals, detected at very low radio frequencies, are an incredibly powerful tool for uncovering the hidden gas that directly connects ordinary matter with the formation of new stars. The study discovered that this dark gas is not just sitting still; it’s flowing and shifting, and moving with velocities much higher than previously realized. These turbulent flows can shape how quickly stars can form. The team also found that the brightness of these carbon lines is directly linked to the intense starlight bathing the region, highlighting the powerful role that radiation plays in galactic recycling.

“By making the invisible visible, we can finally track how raw material in our galaxy is transformed from simple atoms into the complex molecular structures that will one day become stars, planets, and possibly life,” Emig explains, “And this is just the beginning of understanding these previously unseen forces.” The NSF GBT has become the world’s premier tool for this kind of research, and even larger surveys of CRRLs (like the GBT Diffuse Ionized Gas Survey at Low Frequencies) are underway to explore other star-forming regions of the Milky Way. The insights gleaned here will help astronomers around the world model how our Galaxy—and potentially others—builds massive clouds for stars to form in.

Source: National Radio Astronomy Observatory (NRAO)/News

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About GBO

The Green Bank Observatory, part of the National Radio Astronomy Observatory, is a facility of the U.S. National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

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One sixth of the sky with the telescope SRG/eROSITA

Current status of the all-sky survey in X-rays by SRG: about 1/6 of the entire sky has already been covered. Due to the survey geometry, the individual scans of the observatory intersect near the ecliptic poles, resulting in increased sensitivity. The inset shows a small region enlarged and a PLANCK map of the same region in comparison. © IKI, MPA

A little more than a month has passed since the beginning of the regular all-sky survey of the SRG observatory, moving on a halo orbit around the Sun-Earth Lagrange point L2. The spacecraft is at a distance of one and a half million kilometers from Earth, rotating around an axis directed towards the Sun. Since the start of the scan, the ART-XC and eROSITA telescopes have already covered more than 1/6 of the entire celestial sphere and demonstrated the excellent capabilities of SRG in mapping the X-ray sky. By mid-June 2020, the scientists will have the first map of the entire sky, and after four years, each part of the sky will be covered 8 times, increasing the sensitivity of the survey by a record 20-30 times compared to the existing one by the ROSAT satellite.

The image shows a map of half the sky in the 0.4–2 keV energy range, obtained by the SRG/eROSITA telescope. The axes of the observatory telescopes draw large circles in the sky passing through the north and south ecliptic poles. The dark band associated with the absorption of soft X-ray radiation by gas and dust in the Galaxy Plane is clearly visible on the map. The bright diffuse region on the right side of the map is the famous North Polar Spur, an area of ​​increased brightness of radio emission in the form of an arc. Another bright area near the Plane of the Galaxy is the most powerful star-forming region in our Galaxy, known as Cygnus X. Outside of these areas, the X-ray radiation is dominated by numerous active galactic nuclei and clusters of galaxies.

The resolution of the map of the whole sky shown in the figure does not allow one to see individual sources, although more than ten thousand of them have already been registered. To illustrate the capabilities of the telescope, the inset shows a small portion of the sky (2x2 degrees) with better resolution. For comparison the PLANCK (ESA) SZ-map of the same region is shown. The place where the inset was taken from is shown in the large image as a small square near the North ecliptic pole. Near the ecliptic poles the individual scans of the observatory intersect.

The Spectrum RG Observatory continues to scan, and every day it adds a 1-degree-wide strip to this map. The images shown here are based on the data from the Russian share of observing time of the SRG/eROSITA telescope.

Contacts

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Source: Max Planck Institute for Astrophysics/News

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Cygnus-X: the cool swan glowing in flight

This new view of the Cygnus-X star-formation region by Herschel highlights chaotic networks of dust and gas that point to sites of massive star formation.

The image combines data acquired with the PACS instrument at 70 micron (corresponding to the blue channel) and 160 micron (corresponding to the green channel) and with the SPIRE instrument at 250 micron (corresponding to the red channel). The observations were made on 24 May 2010 and 18 December 2010. North is to the lower-right and east to the upper-right.

Credits: ESA/PACS/SPIRE/Martin Hennemann & Frédérique Motte, Laboratoire AIM Paris-Saclay, CEA/Irfu – CNRS/INSU – Univ. Paris Diderot, France. HI-RES JPEG (Size: 2381 kb)

An annotated version of Herschel’s view of Cygnus-X highlighting numerous dense sites of new star formation in the right-hand complex, and the swan-like structure in the left-hand portion of the scene. Powerful radiation and winds from thousands of stars in the OB2 complex undetected at Herschel’s long wavelengths have partly cleared and heated surrounding material, visible as the diffuse blue glow in the centre of the image. A supergiant star identified as G79.29+0.46 has likely ejected the ring of material seen at the bottom of the image.

Credits: ESA/PACS/SPIRE/Martin Hennemann & Frédérique Motte, Laboratoire AIM Paris-Saclay, CEA/Irfu – CNRS/INSU – Univ. Paris Diderot, France. HI-RES JPEG (Size: 7952 kb)

Chaotic networks of dust and gas signpost the next generations of massive stars in this stunning new image of the Cygnus-X star-nursery captured by ESA’s Herschel space observatory.

Cygnus-X is an extremely active region of massive-star birth some 4500 light-years from Earth in the constellation of Cygnus, the Swan.

Using Herschel’s far-infrared eyes, astronomers can seek out regions where dust has been gently heated by stars, pointing them to dense clumps of gas where new generations of stars are forming.

Bright white areas highlight zones where large stars have recently formed out of turbulent clouds, especially evident in the chaotic network of filaments seen in the right-hand portion of the image.

Here, dense knots of gas and dust mark intersections where filaments meet and collapse to form new stars, and where bubble-like structures are carved by their immense radiation.

In the centre of the image, fierce radiation and powerful stellar winds from stars undetected at Herschel’s wavelengths have partly cleared and heated interstellar material, which then glows blue in this representation.

The left-hand part of the scene is dominated by a pillar of gas whose shape resembles that of the neck of a swan.

Below and to the right, a shell of gas and dust has likely been ejected from a supergiant star at its centre, but which is not seen directly in this image.

Strings of compact red objects scattered throughout the scene map the cold seeds of future generations of stars.

The image highlights the unique capabilities of Herschel to probe the birth of large stars and their influence on the surrounding interstellar material with a level of detail at far-infrared wavelengths that has never before been available.

For further information, please contact:

Markus Bauer
ESA Science and Robotic Exploration Communication Officer
Tel: +31 71 565 6799
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Email: markus.bauer@esa.int

Göran Pilbratt
ESA Herschel Project Scientist
Research and Scientific Support Department
Science and Robotic Exploration Directorate
ESA, The Netherlands
Tel: +31 71 565 3621
Email: gpilbratt@rssd.esa.int

Before They Were Stars: New Image Shows Space Nursery

The Cygnus-X star-forming region is located 4,600 light-years from Earth and spans more than 600 light-years. It contains 10 times as much gas as the Orion Nebula - enough to make over three million Suns. This infrared photograph from the Spitzer Space Telescope reveals more than a thousand protostars in the earliest stages of forming. Light of 3.6 microns is color-coded blue: 4.5-micron light is blue-green; 8.0-micron light is green; and 24-micron light is red. Credit: NASA/JPL-Caltech/J. Hora (CfA). High Resolution Image (jpg) - Low Resolution Image (jpg)

Austin, TX - The stars we see today weren't always as serene as they appear, floating alone in the dark of night. Most stars, likely including our sun, grew up in cosmic turmoil - as illustrated in a new image from NASA's Spitzer Space Telescope.

The image shows one of the most active and turbulent regions of star birth in our galaxy, a region called Cygnus X. The choppy cloud of gas and dust lies 4,500 light-years away in the constellation Cygnus the Swan. Cygnus X was named by radio astronomers, since it is one of the brightest radio regions in the Milky Way. (It should not be confused with the black hole Cygnus X-1.)

Cygnus X, which spans an area of the sky larger than 100 full moons, is home to thousands of massive stars, and many more stars around the size of our sun or smaller. Spitzer has captured an infrared view of the entire region, which is bubbling with star formation.

"Spitzer captured the range of activities happening in this violent cloud of stellar birth," said Joe Hora of the Harvard-Smithsonian Center for Astrophysics, who is the principal investigator of the research. "We see bubbles carved out from massive stars, pillars of new stars, dark filaments lined with stellar embryos and more."

The majority of stars are thought to form in huge star-forming regions like Cygnus X. Over time, the stars dissipate and migrate away from each other. It's possible that our sun was once packed tightly together with other, more massive stars in a similarly chaotic, though less extreme, region.

The turbulent star-forming clouds are marked with bubbles, or cavities, which are carved out by radiation and winds from the most massive of stars. Those massive stars tear the cloud material to shreds, terminating the formation of some stars, while triggering the birth of others.

"One of the questions we want to answer is how such a violent process can lead to both the death and birth of new stars," said Sean Carey, a team member from NASA's Spitzer Science Center at the California Institute of Technology. "We still don't know exactly how stars form in such disruptive environments."

Infrared data from Spitzer is helping to answer questions like these by giving astronomers a window into the dustier parts of the complex. Infrared light travels through dust, whereas visible light is blocked. For example, embryonic stars blanketed by dust pop out in the Spitzer observations. In some cases the young stars are embedded in finger-shaped pillars of dust, which line the hollowed-out cavities and point toward the central, massive stars. In other cases, these stars can be seen lining very dark, snake-like filaments of thick dust.

Another question scientists hope to answer is how these pillars and filaments are related.

"We have evidence that the massive stars are triggering the birth of new ones in the dark filaments, in addition to the pillars, but we still have more work to do," said Hora. "The biggest results from this survey are yet to come."

Infrared light in this image has been color-coded according to wavelength. Light of 3.6 microns is blue: 4.5-micron light is blue-green; 8.0-micron light is green; and 24-micron light is red. These data were taken before the Spitzer mission ran out of its coolant in 2009, and began its "warm" mission.

This release is being issued jointly with the Jet Propulsion Laboratory.

NASA’s Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

For more information, contact:

David A. Aguilar
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Source: HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS