Mapping the Universe’s Hidden Framework
As astronomers peer deeper into our universe, a hidden architecture is coming into clearer focus, revealing an unseen framework that has quietly guided our universe’s evolution for billions of years.
In late January, NASA released an ultra-high resolution map of dark matter—an invisible form of matter that doesn’t emit, absorb, or reflect light—that was created using data from the James Webb Space Telescope (JWST) that offers the clearest map yet of how dark matter shapes the universe on its largest scales.
Published in Nature Astronomy, the research traces dark matter’s gravitational influence by measuring subtle distortions in the shapes of distant galaxies that are caused by massive structures bending light as it travels across the cosmos.
Illinois Tech Assistant Professor of Physics Emily Leiner says the map represents a major step forward compared to maps built using data from the Hubble Space Telescope.
“It’s bigger, and it’s higher resolution,” she says. “The JWST observations are using way more galaxies to put together this map across a larger region of the sky.”
The technique that makes this map possible is called weak gravitational lensing. As light from distant galaxies travels toward Earth, it passes massive structures—comprised of both luminous (or bright) and dark matter—that gently warp its path. By measuring these tiny distortions across hundreds of thousands of background galaxies, astronomers can reconstruct where mass is concentrated, even if that mass is invisible.
The resulting map reveals a universe not shaped by randomness but by structure.
“If you didn’t know anything about the structure of the universe, you might think that galaxies are randomly distributed,” Leiner says. “It’s very clear that they are not. They are distributed on what we call the cosmic web.”
Dark matter forms this vast cosmic web with dense clusters of galaxies connected via thin filaments, surrounded by enormous voids where almost no matter—luminous or dark—exists. Importantly, this hidden framework closely aligns with the distribution of visible galaxies, reinforcing long-standing models of how the universe evolved.
Better understanding the relationship between dark matter and luminous matter is crucial, particularly because most of the universe’s mass remains unseen.
“It’s a little haunting to think that 85 percent of the universe’s mass, we just don’t know what it is,” says Leiner. “JWST has revealed deeper into the universe than we’ve ever seen before. This is one of many exciting results that are coming out of that mission.”
