Scientists using NASA's James Webb Space Telescope have assembled the most detailed and highest-resolution map of dark matter ever created, revealing the hidden gravitational scaffolding that shaped the structure of the universe over billions of years. The research, published Monday in the journal Nature Astronomy, analyzed nearly 800,000 galaxies observed across 255 hours as part of the COSMOS-Web survey, the largest observing program from the telescope's first year of scientific operations. The resulting map offers double the resolution of any previous dark matter map.
The international team, jointly led by researchers from Durham University, NASA's Jet Propulsion Laboratory, and the Ecole Polytechnique Federale de Lausanne in Switzerland, mapped a region of sky in the constellation Sextans covering an area approximately 2.5 times larger than the full Moon. Using a technique called weak gravitational lensing, the scientists measured how gravity from invisible mass bends the light of roughly 250,000 distant background galaxies, producing subtle shape distortions that reveal the distribution of unseen matter. The map resolved dark matter structures dating back 8 to 10 billion years, a critical period for galaxy formation.
Lead author Diana Scognamiglio, an observational cosmologist at NASA's Jet Propulsion Laboratory, stated that the James Webb Space Telescope is like putting on a new pair of glasses for the universe, seeing fainter and more distant galaxies with much sharper detail than ever before. She noted that the map represents the largest dark matter map produced with Webb and is twice as sharp as any dark matter map made by other observatories. The map measured the shapes of 129 galaxies per square arcminute, containing approximately 10 times more galaxies than maps of the same region produced by ground-based observatories and twice as many as those made by the Hubble Space Telescope.
The findings revealed a strong correlation between galaxy clusters and dark matter concentrations throughout the mapped region. Professor Richard Massey of Durham University explained that wherever normal matter is found in the universe today, dark matter is also present. The research demonstrated that dark matter's gravity pulled ordinary matter toward it throughout cosmic history, effectively acting as the backbone and foundational blueprint upon which visible galaxies assembled. This confirms theoretical predictions about the role dark matter plays in structuring the large-scale architecture of the cosmos.
The COSMOS-Web survey examined the same patch of sky for 255 hours, building upon a pioneering 2007 study that produced the first detailed dark matter map of the same field using the Hubble Space Telescope. The Webb data revealed previously invisible filaments, clusters, and underdensities with unprecedented clarity. The researchers achieved this breakthrough by exploiting Webb's infrared sensitivity, which allowed them to detect and measure far more distant and faint galaxies than any previous instrument.
The team plans to extend this work using NASA's upcoming Nancy Grace Roman Space Telescope, which is expected to map dark matter over an area 4,400 times larger than the COSMOS region. However, Roman will not match Webb's spatial resolution, meaning that more detailed views of dark matter structure will require a next-generation telescope such as the proposed Habitable Worlds Observatory. The study represents a significant step toward constructing a three-dimensional map of dark matter distribution across the observable universe.
Dark matter accounts for approximately 27 percent of the total mass and energy content of the universe yet cannot be directly observed because it does not emit, absorb, or reflect light. Its existence is inferred from gravitational effects on visible matter, radiation, and the large-scale structure of the cosmos. Understanding its distribution is considered essential to explaining how galaxies formed and evolved over the 13.8 billion year history of the universe.
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