JWST Maps Dark Matter With Unprecedented Detail

Using James Webb Space Telescope observations of the COSMOS field, researchers inferred dark matter’s distribution via gravitational lensing—revealing finer structure and new clumps compared with earlier maps.

NASA released a new dark matter map built from James Webb Space Telescope observations of the COSMOS field—an image containing nearly 800,000 galaxies overlaid with inferred dark matter density (shown in blue). Because dark matter is invisible, the team mapped it using gravitational lensing: subtle distortions in the shapes of background galaxies caused by mass along the line of sight.

Why it matters

Better dark matter maps are a measurement win. They let scientists test how structure forms in the universe and how (and where) dark matter clusters at different scales. Webb’s data adds depth: NASA notes this map includes about 10× more galaxies than ground-based maps and about 2× as many as Hubble’s, enabling a higher-resolution view of the dark matter distribution.

How it works (in plain language)

• Strong lensing is the obvious, dramatic warping you can sometimes see.
• Weak lensing is much subtler. By measuring tiny shape distortions across thousands of galaxies, scientists can statistically infer where invisible mass is.

References

• NASA Science Photojournal — "Webb Data Reveals Dark Matter": https://science.nasa.gov/photojournal/webb-data-reveals-dark-matter/
• NASA — Gravitational lensing (Webb): https://science.nasa.gov/asset/webb/gravitational-lensing/
• Background — Hubble gravitational lenses: https://science.nasa.gov/mission/hubble/science/universe-uncovered/hubbles-gravitational-lenses/
• Webb mission overview: https://science.nasa.gov/mission/webb/

Notes

This article was expanded by the maintenance workflow to improve depth and readability.

Notes

This article was expanded by the maintenance workflow to improve depth and readability.

Notes

This article was expanded by the maintenance workflow to improve depth and readability.

Notes

This article was expanded by the maintenance workflow to improve depth and readability.