The James Webb Telescope has created the most detailed dark matter map yet, covering nearly 800,000 galaxies.

Relying on the latest observation data of the James Webb Space Telescope, astronomers have drawn the most accurate distribution map of dark matter in the universe so far, clearly showing the "skeleton of the universe" spanning billions of light-years and an invisible fiber network composed of dark matter on a large scale for the first time.Relevant research results have been published in "Nature Astronomy". The team used Webb's infrared detection capabilities to conduct long-term observations and statistical analysis of nearly 800,000 galaxies in the famous COSMOS deep space observation area, thereby reconstructing a detailed picture of how dark matter has dominated the formation of large-scale structures since the early days of the universe.

Dark matter is believed to account for about four-fifths of the total matter in the universe, but it neither emits nor absorbs light itself. It cannot be directly observed by humans. Its existence and distribution can only be "inferred" through its gravitational effect on visible matter and light. This study adopted the "weak gravitational lensing effect" method: when large-scale dark matter forms filaments in the universe, its gravity will slightly bend the light from more distant background galaxies, causing these galaxies to be slightly stretched and distorted in telescope imaging, just like the reflections seen through a hazy mirror or undulating water. The scientific research team stared at the same patch of sky for a total of 255 hours in the first year of Webb's operation. By accurately counting the shape distortion of hundreds of thousands of background galaxies, they inverted the distribution of foreground dark matter and then generated a high-resolution dark matter map.

This observation area was famous for studying galaxy formation and cluster structure as early as the Hubble Telescope era. Now Webb's infrared instrument has pushed the field of view further into the depths of the earlier universe, capturing older and fainter early galaxies, allowing scientists to trace the process of dark matter "building cosmic scaffolding" forward in the time dimension. Diana Scognamiglio of NASA's Jet Propulsion Laboratory, one of the leaders of the study, said that while the new map remains generally consistent with previous observations, its resolution and details have been significantly improved, allowing the "invisible framework" of the large-scale structure of the universe to be presented in such a clear way for the first time.

By superimposing the density distribution of dark matter and the distribution of galaxies, the researchers observed that galaxies are arranged along dark matter fibers like "beads on a string", verifying the structural evolution picture of "heavy dark matter, light light": first, dark matter formed uneven clumps and filamentous structures in the early universe, and then its gravity continuously gathered ordinary matter, and its density accumulated in local areas enough to ignite stars and form galaxies and planetary systems. Richard Massey, a physicist at Durham University in the UK who participated in the study, vividly pointed out that dark matter constitutes the "gravitational scaffolding" of all structures in the universe. The reason why large galaxies such as the Milky Way can maintain stability for billions of years is largely due to "hanging" on this web woven by dark matter.

The new results not only provide a shocking "base map" of the universe, but also lay an important observation benchmark for future exploration of the nature of dark matter. Rachel Mandelbaum, a physicist at Carnegie Mellon University who was not involved in the research, pointed out that this batch of data will be used by colleagues for a long time and will help answer basic questions such as how matter in the universe is distributed and how galaxies evolve within the framework of dark matter. Next, projects such as the European Space Agency's Euclid Space Telescope, the planned Nancy Grace Roman Telescope in the United States, and the Vera C. Rubin Observatory in Chile will carry out sky surveys in a larger sky area, different wavebands and longer time scales, mutually confirming and complementing the high-precision dark matter map provided by Webb, promoting the construction of a more complete three-dimensional universe model, and gradually approaching the truth about key physical properties such as the mass and motion characteristics of dark matter particles.