WASHINGTON, Jan 26, 2026, 12:14 (EST)
- Scientists used NASA’s James Webb Space Telescope to produce a new high-resolution dark matter map of the COSMOS field
- The map relies on weak gravitational lensing, using tiny shape distortions in distant galaxies to infer invisible mass
- Researchers say it sharpens tests of how galaxies formed and sets a benchmark for wider future surveys
Astronomers using NASA’s James Webb Space Telescope have produced the most detailed map yet of dark matter across the COSMOS field, charting an invisible substance that makes up about 85% of the universe’s matter. The team said the data fits the leading Lambda-CDM model — shorthand for dark energy (Lambda) and cold dark matter — and Diana Scognamiglio called Webb “a new pair of glasses for the universe” while co-author Jacqueline McCleary dubbed dark matter halos the “nurseries of galaxies.” (Reuters)
The sharper map matters because researchers use it to test how galaxies grow and how matter clumps over cosmic time, a question that sits behind everything from galaxy clusters to the Milky Way. Scognamiglio said the Webb-based map is “twice as sharp” as earlier dark matter maps and lets scientists see the universe’s “invisible scaffolding” with more detail. (NASA)
Dark matter does not emit or absorb light, so scientists hunt it through gravity — by measuring how it bends the light from far-off galaxies, a phenomenon called gravitational lensing. Scognamiglio said the new view helps scientists “see everything more clearly,” and Harvard-Smithsonian astrophysicist Rutuparna Das, who was not involved, told AP: “Our home is the universe.” (AP News)
The map covers a patch of sky about 2.5 times larger than the full Moon in the constellation Sextans, a region watched for years in the Cosmic Evolution Survey, or COSMOS. Webb spent about 255 hours on the field and logged nearly 800,000 galaxies, then researchers used the weak-lensing signal — tiny, systematic distortions in galaxy shapes — to reconstruct where dark matter sits. (NASA Jet Propulsion Laboratory (JPL))
McCleary said Webb’s camera lets the team work with distant galaxies that look small and noisy and “map those shapes very carefully.” She described the result as “a snapshot” of the universe when it was about half its current age. (Northeastern Global News)
Earlier attempts relied on Hubble Space Telescope imaging of the same COSMOS field, and scientists are now stacking Webb’s deeper view on top to verify older analyses and dig out new structures. “This is stunning,” Scognamiglio said, and National Geographic noted that the Webb result lands as NASA’s upcoming Roman Space Telescope and Europe’s Euclid telescope aim to push dark-matter mapping to much wider areas. (National Geographic)
NASA’s own breakdown puts the universe at roughly 5% ordinary matter, about 27% dark matter and about 68% dark energy, an unknown ingredient tied to the universe’s accelerating expansion. That accounting is why mapping dark matter’s distribution — not just detecting it — has become a central job for cosmologists. (NASA Science)
A Durham University-led write-up described the Webb map as showing how dark matter’s gravity pulled ordinary matter into the earliest structures, with dense clumps linked by filaments that form what astronomers call the cosmic web. Richard Massey said, “They grew up together,” referring to dark matter and normal matter evolving side by side in the same places. (Phys)
NASA uses “dark energy” as a catch-all name for whatever is driving the accelerating expansion of the universe. If future maps show dark matter’s clumping pattern doesn’t match expectations, it could sharpen — or unsettle — ideas about how dark energy behaves over cosmic history. (NASA Science)
But the new image is still an indirect portrait: researchers infer dark matter from gravity and must measure extremely subtle weak-lensing distortions, leaving results sensitive to how well galaxy shapes and distances are measured. NASA notes that “no one knows exactly” what dark matter is, so the map tightens the chase without naming the quarry. (NASA Science)
NASA says the Roman Space Telescope is built for speed and scale — capturing 300-megapixel images and surveying the sky far faster than Hubble while keeping similar resolution. Webb does the opposite job, taking narrow but deep views that can anchor lensing maps and let astronomers follow up on the rarest, faintest targets those surveys turn up. (NASA Science)
NASA’s mission timeline shows Webb launched on Dec. 25, 2021, after decades of planning and testing — the kind of long lead time that tends to pay off in sudden leaps like this week’s dark matter map. (NASA Science)
