NASA Reveals New Details About Dark Matter’s Influence on Universe
Thanks to the unprecedented sensitivity of the Webb telescope, scientists are learning more about the influence of dark matter on stars, galaxies and even planets like Earth.
Scientists using data from NASA’s James Webb Space Telescope have produced one of the most detailed, high-resolution maps of dark matter ever produced. It shows how invisible, ghostly matter overlaps and intertwines with “ordinary” matter, the matter that makes up stars, galaxies, and everything else 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 shaped the universe on the largest scales—clusters of galaxies spanning millions of light years—that ultimately gave rise to galaxies, stars, and planets like Earth.
“This is the largest dark matter map we have made with Webb, and it is 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 looked at a blurry image of dark matter. Now we see the invisible scaffolding of the universe in stunning detail, thanks to Webb’s incredible resolution.”
Dark matter does not emit, reflect, absorb, or even block light, and it passes through ordinary matter like a ghost. But it interacts with the universe through gravity, which the map shows with a new level of clarity. The evidence for this interaction lies in the degree of overlap between dark matter and ordinary matter. According to the paper’s authors, Webb’s observations confirm that this close alignment cannot be a coincidence but is instead due to dark matter’s gravity pulling ordinary matter toward it throughout cosmic history.
“Wherever we see a large 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 such clusters, we also see a string of dark matter,” said Richard Massey, an astrophysicist at the University of Durham in the United Kingdom and co-author of the new study. “It’s not just that they have the same shapes. This map shows us that dark matter and ordinary matter have always been in the same place. They grew together.”
Located in the Sextans constellation, the area covered by the new map is a section of the sky approximately 2.5 times larger than the full Moon. A global community of scientists has observed this region with at least 15 ground-based and space-based telescopes for the Cosmic Evolution Survey (COSMOS). Their goal: to precisely measure the location of ordinary matter here, then compare it to the location of dark matter. The first dark matter map of the region was made in 2007 using data from NASA’s Hubble Space Telescope, a project led by Massey and JPL astrophysicist Jason Rhodes, co-author of the paper.
Webb scanned this region for about 255 hours in total and identified nearly 800,000 galaxies, some of which were detected for the first time. Scognamiglio and his colleagues then searched for dark matter by observing how its mass bends space itself, which in turn bends light coming from distant galaxies and heading toward Earth. When observed by researchers, it is as if the light from these galaxies passes through a distorted window.
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 clusters of dark matter and captures a higher-resolution view of areas previously seen by Hubble.
When the universe began, ordinary matter and dark matter were probably sparsely distributed. Scientists believe that dark matter began to clump together first and that these clumps of dark matter then pulled ordinary matter together, creating regions with enough matter for stars and galaxies to begin to form.
In this way, dark matter has determined the large-scale distribution of galaxies in the universe. And by causing the formation of galaxies and stars to begin earlier than they otherwise would have, the influence of dark matter also played a role in creating the conditions necessary for the eventual formation of planets. Indeed, the first generations of stars transformed hydrogen and helium – which made up the vast majority of atoms in the early universe – into the rich array of elements that make up planets like Earth today. In other words, dark matter gave complex planets more time to form.
“This map provides stronger evidence that without dark matter, we might not have the elements in our galaxy that allowed life to arise,” Rhodes said. “Dark matter is not something we encounter in our daily lives on Earth, or even in our solar system, but it has definitely influenced us.”
Scognamiglio and some of his co-authors will also map dark matter with NASA’s upcoming Nancy Grace Roman Space Telescope over an area 4,400 times larger than the COSMOS region. Roman’s main scientific goals are to learn more about the fundamental properties of dark matter and how they may or may not have changed over the course of cosmic history. But Roman’s maps won’t surpass Webb’s spatial resolution. A more detailed examination of dark matter will only be possible with a next-generation telescope like the Habitable Worlds Observatory, NASA’s next flagship astrophysics concept.
The James Webb Space Telescope solves the mysteries of our solar system, looks beyond distant worlds to other stars, and probes 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
Calla Cofield / Ian O’Neill
Jet Propulsion Laboratory, Pasadena, California.
626-808-2469 / 818-354-2649
calla.e.cofield@jpl.nasa.gov / ian.j.oneill@jpl.nasa.gov
2026-002
