Astronomers have produced the most detailed map of dark matter to date using NASA's James Webb Space Telescope, revealing how this invisible substance shaped the formation of galaxies and planets. The research, involving teams from Durham University, NASA's Jet Propulsion Laboratory, and Switzerland's École Polytechnique Fédéral de Lausanne, was published in Nature Astronomy. The map highlights dark matter's gravitational role in pulling ordinary matter together since the universe's early days.
The new map offers unprecedented insight into dark matter, which cannot be seen directly but influences the cosmos through gravity. At the universe's beginning, dark matter likely clumped first, its gravity drawing in ordinary matter to form dense regions where stars and galaxies emerged. This process established the distribution of galaxies observed today and enabled conditions for planets and life to develop.
Dr. Gavin Leroy, co-lead author from Durham University's Institute for Computational Cosmology, explained: "By revealing dark matter with unprecedented precision, our map shows how an invisible component of the Universe has structured visible matter to the point of enabling the emergence of galaxies, stars, and ultimately life itself. This map reveals the invisible but essential role of dark matter, the true architect of the Universe, which gradually organizes the structures we observe through our telescopes."
The observations targeted a sky region in the constellation Sextans, about 2.5 times the full Moon's size. Over 255 hours, Webb identified nearly 800,000 galaxies, using gravitational lensing—where dark matter's mass bends light from distant objects—to map its distribution. This aligns closely with normal matter maps, confirming dark matter's pull throughout cosmic history.
Professor Richard Massey, another co-author from Durham, noted: "Wherever you find normal matter in the Universe today, you also find dark matter. Billions of dark matter particles pass through your body every second. There's no harm, they don't notice us and just keep going. But the whole swirling cloud of dark matter around the Milky Way has enough gravity to hold our entire galaxy together. Without dark matter, the Milky Way would spin itself apart."
Dr. Diana Scognamiglio from NASA's Jet Propulsion Laboratory added: "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. 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."
The team employed Webb's Mid-Infrared Instrument (MIRI), with Durham contributing to its development, to measure galaxy distances accurately, even through cosmic dust. Future efforts will use the Euclid telescope and NASA's Nancy Grace Roman Space Telescope to map dark matter universe-wide, building on this reference region.