Cosmic map reveals ordinary matter between galaxies

New observations using fast radio bursts reveal that most ordinary matter lies between galaxies, reshaping cosmology.

Cosmic Map Reveals Ordinary Matter in Intergalactic Space

Astronomers report that about 76 percent of the universe’s ordinary matter lies not in stars or gas inside galaxies, but in the intergalactic medium that fills the space between them. This finding supports long-standing simulations of the cosmic web and reframes where the visible matter of the universe lives.

The study, published in Nature Astronomy, analyzed 69 fast radio bursts from distances spanning from about 11.74 million to more than 9.1 billion light-years. By measuring how the signals are dispersed as they travel through space, researchers estimated the density of matter along each sightline. The Deep Synoptic Array-110, Keck Observatory, and Palomar Observatory helped locate the bursts and tie the measurements to specific regions of the sky.

This discovery shifts the narrative about the universe’s architecture. If most baryons sit in the voids between galaxies, the flow of gas through the cosmic web becomes a central driver of galaxy growth and star formation. It also shows how new tools like FRBs open windows that traditional galaxy surveys miss.

The approach is powerful but still evolving. The results depend on models of gas physics and ionization, and more FRBs will help tighten the map. As data accumulate, scientists will test how this missing matter interacts with dark matter and with feedback processes from stars and black holes.

Highlights

The universe keeps its secrets, but the map grows sharper.