JWST has unveiled the sharpest-ever map of the universe’s hidden cosmic web, reaching back nearly to cosmic dawn.
Astronomers using NASA’s James Webb Space Telescope (JWST) have created the most detailed map ever produced of the cosmic web, the enormous structure that connects galaxies across the universe. Led by researchers at the University of California, Riverside, the team traced this giant network back to a period when the universe was only about one billion years old.
The cosmic web is the vast, skeleton-like framework of the universe. It is made up of massive filaments and sheets of dark matter and gas that surround huge, nearly empty regions of space called voids. Together, these structures form the large-scale architecture of the cosmos, linking galaxies and galaxy clusters across immense distances.
The research, published in The Astrophysical Journal, relied on the largest JWST survey ever conducted, known as COSMOS-Web. Scientists used the survey to study how galaxies have formed and evolved within this interconnected network over 13.7 billion years of cosmic history.
James Webb Space Telescope Expands Our View of the Cosmos
Since launching in 2021, JWST has transformed astronomy with its exceptional sensitivity and image clarity. Its infrared instruments can detect faint, distant galaxies that earlier telescopes could not observe, allowing scientists to look farther back in time and see through clouds of cosmic dust.
To take advantage of those capabilities, an international team developed COSMOS-Web, the largest General Observer (GO) program selected for JWST. The GO program is the main system astronomers use to obtain observing time on the telescope. The survey covers a continuous section of sky roughly equal to the size of three full Moons and was specifically designed to map the cosmic web.
“JWST has completely changed our view of the universe, and COSMOS-Web was designed from the start to give us the wide, deep view we need to see the cosmic web,” said Hossein Hatamnia, a graduate student at UCR and Carnegie Observatories, and lead author of the study. “For the first time, we can study the evolution of galaxies in cluster and filamentary structures across cosmic time, all the way from when the universe was a billion years old up to the nearby universe.”
The nearby universe refers to the region within approximately 1 billion light-years of Earth. A light-year, equal to about 5.88 trillion miles, measures how far light travels in one year.
Cosmic Web Map Reveals Hidden Structures
Bahram Mobasher, a distinguished professor of physics and astronomy at UCR and Hatamnia’s advisor, said the new JWST data provides a far more detailed view of large-scale cosmic structures than previous observations from the Hubble Space Telescope. Comparing the two datasets side by side reveals that many structures once blurred together can now be clearly separated and examined in much finer detail.
“The jump in depth and resolution is truly significant, and we can now see the cosmic web at a time when the universe was only a few hundred million years old, an era that was essentially out of reach before JWST,” Mobasher said. “What used to look like a single structure now resolves into many, and details that were smoothed away before, are now clearly visible.”
Hatamnia explained that the improvement comes from two key strengths of JWST working together.
“The telescope detects many more faint galaxies in the same patch of sky, and the distances to those galaxies are measured far more precisely,” he said. “Each galaxy can therefore be placed into the correct slice of cosmic time, sharpening the map’s resolution.”
Public Release of COSMOS-Web Data
Continuing COSMOS’s tradition of open science, the research team is making the large-scale structure maps publicly available.
“The pipeline used to build the map, the catalog of 164,000 galaxies and their cosmic density, and a video showing the cosmic web evolving across billions of years, has been released to the public,” Mobasher said.
Reference: “Large-scale Structure in COSMOS-Web: Tracing Galaxy Evolution in the Cosmic Web up to z ∼ 7 with the Largest JWST Survey” by Hossein Hatamnia, Bahram Mobasher, Sina Taamoli, Jeyhan S. Kartaltepe, Caitlin M. Casey, Hollis B. Akins, Malte Brinch, Nima Chartab, Nicole E. Drakos, Andreas L. Faisst, Steven L. Finkelstein, Maximilien Franco, Finn Giddings, Ghassem Gozaliasl, Ali Hadi, Aryana Haghjoo, Santosh Harish, Olivier Ilbert, Pascale L. Jablonka, Shuowen Jin, Ali Ahmad Khostovan, Anton M. Koekemoer, Ronaldo Laishram, Daizhong Liu, Matteo Maturi, Henry Joy McCracken, Crystal L. Martin, Lauro Moscardini, Diana Scognamiglio, Marko Shuntov, Greta Toni, Alexander de la Vega, John R. Weaver and Lilan Yang, 6 May 2026, The Astrophysical Journal.
DOI: 10.3847/1538-4357/ae5bac
Scientists from the U.S., Denmark, Chile, France, Finland, Switzerland, Japan, China, Germany, and Italy also contributed to the study. The research received support from grants provided through the European Union’s Horizon 2020 research and innovation program.
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.