Astronomers have unveiled a finely detailed cosmic map constructed from observations made by NASA's James Webb Space Telescope (JWST), shedding light on the elusive substance known as dark matter that constitutes over a quarter of the universe's total mass-energy content. Unlike ordinary matter—including everything visible such as stars, planets, and living beings, which accounts for roughly 5% of the cosmos—dark matter does not emit, absorb, or reflect light, rendering it invisible to direct detection.
This invisibility requires scientists to infer dark matter's presence through its gravitational effects on visible matter and the bending of light from distant galaxies, a phenomenon known as gravitational lensing. By examining these subtle distortions, researchers are piecing together the large-scale structure of the universe and understanding how dark matter interconnects galaxy formations.
The newly published map, documented in the journal Nature Astronomy, harnesses JWST's advanced imaging quality, delivering resolution twice as fine as earlier large-scale maps created with the Hubble Space Telescope. Covering an extensive portion of the sky, it captures data on hundreds of thousands of galaxies spanning up to ten billion years in the past. This clarity reveals new galaxy clusters and the filaments of dark matter that connect them, forming the cosmic web—a framework underpinning the arrangement of matter throughout the universe.
Diana Scognamiglio, a contributor from NASA’s Jet Propulsion Laboratory involved with the research, remarked on the improved observational capability: "Now, we can see everything more clearly," highlighting the leap forward in detail and the extensive coverage provided by this survey.
Dark matter, though imperceptible in everyday life, permeates and flows through us continually while shaping cosmic evolution. Astrophysicist Rutuparna Das of the Harvard-Smithsonian Center for Astrophysics, who was not part of this study, reflected on humanity's intrinsic curiosity about our origins, emphasizing that understanding the universe’s composition—including dark matter—is vital to comprehending the story of existence. She noted, "Our home is the universe and we want to understand what the nature of it is." The research advances this aim by unraveling how dark matter has aggregated over billions of years, forming the backbone of cosmic structures.