Scientists have been looking at stars for hundreds of years without realizing that the majority of the universe lies hidden. Only one-sixth is made up of the material that we can see like planets and galaxies. Dark matter is the rest, an eerie presence which neither emits or absorbs light but shapes the architecture of our universe.
With the James Webb Space Telescope, which has an extraordinary level of sensitivity, the scientists have created one of the most precise and detailed maps ever made of dark matter.
This map confirms the astronomers’ ideas and also shows that dark matter is mixed with visible matter to form a framework which shapes stars, galaxies and planets such as Earth.
The most direct way to investigate dark matter is through weak gravitational lenses, which bend light from distant galaxies due to intervening masses. Hubble, and other ground-based telescopes were used by astronomers to track these distortions for decades. Webb has changed the picture.
This is by far the most detailed dark matter image we have ever made. It’s also twice as sharp as other dark matter images made using other observatories.” Diana Scognamiglio is the lead author and astrophysicist of this paper at NASA Jet Propulsion Laboratory, located in Southern California.
“Previously, dark matter was a fuzzy picture. Webb’s amazing resolution allows us to see the unseen scaffolding in the universe with stunning clarity.
The cosmic web is formed by filaments of lower density connecting dense regions of dark material. The pattern is more pronounced in Webb’s data than the Hubble images. Dark matter tends to influence the structure of ordinary matter including galaxies. Credit: NASA/STSci/A. Pagan
This new map is centered on an area of the sky that spans an approximate 2,5 times greater surface than the Moon. The region is a long-time cosmic laboratory. COSMOS, the Cosmic evolution survey (cosmos), has gathered data from 15 telescopes in order to compare visible and invisible matter.
In 2007, Hubble was used to map the dark matter in this region. The project, led by Jason Rhodes from JPL and Richard Massey from Durham University, took place in 2007.
Webb studied this area for 255-hours and identified nearly 800,000. Many of these galaxies were visible for the very first time. Scognamiglio and his team were able to trace the contours of hidden dark matter by studying their warped light. It’s almost as if light from galaxies passed through an distorted windowpane to reveal gravity’s invisible hand.
Webb’s map contains ten more galaxies than previous ground surveys, and two more than Hubble. The map also shows new dark matter clusters and provides a better picture than what has been seen previously. Webb’s Mid-Infrared Instrument, or MIRI for short, helped by finding galaxies that were hidden under dust. It also measured their distances with greater accuracy.
Richard Massey (coauthor) stressed the close relationship between visible and invisible. This map shows that regular and dark matter were always in the same location. “They grew up together.”
The upcoming Nancy Grace Roman Space Telescope, which will cover an area 4400 times bigger than COSMOS, offers superior resolution to Webb.
Roman’s missions will test the fundamental properties of dark matter and determine if they have evolved over time. Roman’s maps will not surpass Webb in sharpness. Astronomers are looking to NASA’s future Habitable Worlds Observatory concept for this, as it promises more precise glimpses of the invisible structure of the universe.
The dark matter is still a mystery, the silent architect behind galaxies. With Webb’s new lens, researchers are finally able to sketch its outline with greater clarity. This new map represents more than just an important scientific achievement. The map shows that we only see a small part of the entire universe. Hidden parts will still determine how planets and stars and possibly even life, grow into the future.
Journal Reference
- Scognamiglio, D., Leroy, G., Harvey, D. The et all An ultra-high-resolution map of (dark) matter. Nat Astron (2026). DOI: 10.1038/s41550-025-02763-9
