I only started creating a smart home last year, so nearly all of my devices communicate via Matter. For the most part, things have just worked. As I try out different smart home hubs and troubleshoot the occasional issue, there’s only one simple thing I wish I did from the beginning that would have saved me a lot of frustration—write down my Matter pairing codes.

With the Webb telescope’s unprecedented sensitivity, scientists are learning more about dark matter’s influence on stars, galaxies, and even planets like Earth.

Scientists using data from NASA’s James Webb Space Telescope have made one of the most detailed, high-resolution maps of dark matter ever produced. It shows how the invisible, ghostly material overlaps and intertwines with “regular” matter, the stuff that makes up stars, galaxies, and everything we can see.

Published Monday, Jan. 26, in Nature Astronomy, the map builds on previous research to provide additional confirmation and new details about how dark matter has shaped the universe on the largest scales — galaxy clusters millions of light-years across — that ultimately give rise to galaxies, stars, and planets like Earth.

“This is the largest dark matter map we’ve made with Webb, and it’s twice as sharp as any dark matter map made by other observatories,” said Diana Scognamiglio, lead author of the paper and an astrophysicist at NASA’s Jet Propulsion Laboratory in Southern California. “Previously, we were looking at a blurry picture of dark matter. Now we’re seeing the invisible scaffolding of the universe in stunning detail, thanks to Webb’s incredible resolution.”

Dark matter doesn’t emit, reflect, absorb, or even block light, and it passes through regular matter like a ghost. But it does interact with the universe through gravity, something the map shows with a new level of clarity. Evidence for this interaction lies in the degree of overlap between dark matter and regular matter. According to the paper’s authors, Webb’s observations confirm that this close alignment can’t be a coincidence but, rather, is due to dark matter’s gravity pulling regular matter toward it throughout cosmic history.

“Wherever we see a big cluster of thousands of galaxies, we also see an equally massive amount of dark matter in the same place. And when we see a thin string of regular matter connecting two of those clusters, we see a string of dark matter as well,” said Richard Massey, an astrophysicist at Durham University in the United Kingdom and a coauthor of the new study. “It’s not just that they have the same shapes. This map shows us that dark matter and regular matter have always been in the same place. They grew up together.”

Closer look

Found in the constellation Sextans, the area covered by the new map is a section of sky about 2.5 times larger than the full Moon. A global community of scientists have observed this region with at least 15 ground- and space-based telescopes for the Cosmic Evolution Survey (COSMOS). Their goal: to precisely measure the location of regular matter here and then compare it to the location of dark matter. The first dark matter map of the area was made in 2007 using data from NASA’s Hubble Space Telescope, a project led by Massey and JPL astrophysicist Jason Rhodes, a coauthor of the paper.

Webb peered at this region for a total of about 255 hours and identified nearly 800,000 galaxies, some of which were detected for the first time. Scognamiglio and her colleagues then looked for dark matter by observing how its mass curves space itself, which in turn bends the light traveling to Earth from distant galaxies. When observed by researchers, it’s as if the light of those galaxies has passed through a warped windowpane.

The Webb map contains about 10 times more galaxies than maps of the area made by ground-based observatories and twice as many as Hubble’s. It reveals new clumps of dark matter and captures a higher-resolution view of the areas previously seen by Hubble.

To refine measurements of the distance to many galaxies for the map, the team used Webb’s Mid-Infrared Instrument (MIRI), designed and managed through launch by JPL, along with other space- and ground-based telescopes. The wavelengths that MIRI detects also make it adept at detecting galaxies obscured by cosmic dust clouds.

Why it matters

When the universe began, regular matter and dark matter were probably sparsely distributed. Scientists think dark matter began to clump together first and that those dark matter clumps then pulled together regular matter, creating regions with enough material for stars and galaxies to begin to form.

In this way, dark matter determined the large-scale distribution of galaxies in the universe. And by prompting galaxy and star formation to begin earlier than they would have otherwise, dark matter’s influence also played a role in creating the conditions for planets to eventually form. That’s because the first generations of stars were responsible for turning hydrogen and helium — which made up the vast majority of atoms in the early universe — into the rich array of elements that now compose planets like Earth. In other words, dark matter provided more time for complex planets to form.

“This map provides stronger evidence that without dark matter, we might not have the elements in our galaxy that allowed life to appear,” said Rhodes. “Dark matter is not something we encounter in our everyday life on Earth, or even in our solar system, but it has definitely influenced us.”

Scognamiglio and some of her coauthors will also map dark matter with NASA’s upcoming Nancy Grace Roman Space Telescope over an area 4,400 times bigger than the COSMOS region. Roman’s primary science goals include learning more about dark matter’s fundamental properties and how they may or may not have changed over cosmic history. But Roman’s maps won’t beat Webb’s spatial resolution. More detailed looks at dark matter will be possible only with a next-generation telescope like the Habitable Worlds Observatory, NASA’s next astrophysics flagship concept.

More about Webb

The James Webb Space Telescope is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

To learn more about Webb, visit:

https://science.nasa.gov/webb

Media Contacts

Calla Cofield / Ian O’Neill
Jet Propulsion Laboratory, Pasadena, Calif.
626-808-2469 / 818-354-2649
calla.e.cofield@jpl.nasa.gov / ian.j.oneill@jpl.nasa.gov

2026-002

A team using NASA’s Hubble Space Telescope has uncovered a new type of astronomical object — a starless, gas-rich, dark-matter cloud considered a “relic” or remnant of early galaxy formation. Nicknamed “Cloud-9,” this is the first confirmed detection of such an object in the universe — a finding that furthers the understanding of galaxy formation, the early universe, and the nature of dark matter itself.

“This is a tale of a failed galaxy,” said the program’s principal investigator, Alejandro Benitez-Llambay of the Milano-Bicocca University in Milan, Italy. “In science, we usually learn more from the failures than from the successes. In this case, seeing no stars is what proves the theory right. It tells us that we have found in the local universe a primordial building block of a galaxy that hasn’t formed.”

The results, published in The Astrophysical Journal Letters, were presented at a press conference Monday at the 247th meeting of the American Astronomical Society in Phoenix.

“This cloud is a window into the dark universe,” said team member Andrew Fox of the Association of Universities for Research in Astronomy/Space Telescope Science Institute (AURA/STScI) for the European Space Agency. “We know from theory that most of the mass in the universe is expected to be dark matter, but it’s difficult to detect this dark material because it doesn’t emit light. Cloud-9 gives us a rare look at a dark-matter-dominated cloud.”

The object is called a Reionization-Limited H I Cloud, or “RELHIC.” The term “H I” refers to neutral hydrogen, and “RELHIC” describes a natal hydrogen cloud from the universe’s early days, a fossil leftover that has not formed stars. For years, scientists have looked for evidence of such a theoretical phantom object. It wasn’t until they turned Hubble toward the cloud, confirming that it is indeed starless, that they found support for the theory.

“Before we used Hubble, you could argue that this is a faint dwarf galaxy that we could not see with ground-based telescopes. They just didn’t go deep enough in sensitivity to uncover stars,” said lead author Gagandeep Anand of STScI. “But with Hubble’s Advanced Camera for Surveys, we’re able to nail down that there’s nothing there.”

The discovery of this relic cloud was a surprise. “Among our galactic neighbors, there might be a few abandoned houses out there,” said STScI’s Rachael Beaton, who is also on the research team.

Astronomers think RELHICs are dark matter clouds that couldn’t accumulate enough gas to form stars. They represent a window into the early stages of galaxy formation. Cloud-9 suggests the existence of many other small, dark matter-dominated structures in the universe — other failed galaxies. This discovery provides new insights into the dark components of the universe that are difficult to study through traditional observations, which focus on bright objects like stars and galaxies.

Scientists have studied hydrogen clouds near the Milky Way for many years, but these clouds tend to be much bigger and more irregular than Cloud-9. Compared with other observed hydrogen clouds, Cloud-9 is smaller, more compact, and highly spherical, making it look very different from the others.

The core of this object is composed of neutral hydrogen and is about 4,900 light-years in diameter. Researchers measured the hydrogen gas in Cloud-9 by the radio waves it emits, measuring it to be approximately one million times the mass of the Sun. Assuming that the gas pressure is balancing the dark matter cloud’s gravity, which appears to be the case, researchers calculated Cloud-9’s dark matter must be about five billion solar masses.

Cloud-9 is an example of structures and mysteries that don’t involve stars. Just looking at stars doesn’t give the full picture. Studying the gas and dark matter helps provide a more complete understanding of what’s going on in these systems that would otherwise be unknown.

Observationally, identifying these failed galaxies is challenging because nearby objects outshine them. Such systems are also vulnerable to environmental effects like ram-pressure stripping, which can remove gas as the cloud moves through intergalactic space. These factors further reduce their expected numbers.

The starless relic was discovered three years ago as part of a radio survey by the Five-hundred-meter Aperture Spherical Telescope (FAST) in Guizhou, China, a finding later confirmed by the Green Bank Telescope and the Very Large Array facilities in the United States. But only with Hubble could researchers definitively determine that the failed galaxy contains no stars.

Cloud-9 was simply named sequentially, having been the ninth gas cloud identified on the outskirts of a nearby spiral galaxy, Messier 94 (M94). The cloud is close to M94 and appears to have a physical association with the galaxy. High-resolution radio data shows slight gas distortions, possibly indicating interaction between the cloud and galaxy.

The cloud may eventually form a galaxy in the future, provided it grows more massive — although how that would occur is under speculation. If it were much bigger, say, more than 5 billion times the mass of our Sun, it would have collapsed, formed stars, and become a galaxy that would be no different than any other galaxy we see. If it were much smaller than that, the gas could have been dispersed and ionized and there wouldn’t be much left. But it’s in a sweet spot where it could remain as a RELHIC.

The lack of stars in this object provides a unique window into the intrinsic properties of dark matter clouds. The rarity of such objects and the potential for future surveys is expected to enhance the discovery of more of these “failed galaxies” or “relics,” resulting in insights into the early universe and the physics of dark matter.  

The Hubble Space Telescope has been operating for more than three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.