Astronomers have just revealed the largest collection of galaxy groups ever observed—thanks to the powerful eyes of the James Webb Space Telescope (JWST).
This record-breaking discovery includes nearly 1,700 galaxy groups and stretches across more than 12 billion years of cosmic history, offering a detailed look at how galaxies have grown, changed, and come together over time.
The findings come from a global team of scientists working in a region of the sky known as COSMOS-Web.
The team was led by Ghassem Gozaliasl from Aalto University, who described the discovery as a major leap forward in understanding the universe.
Their work will soon appear in the journal Astronomy and Astrophysics, and one of their stunning images—a galaxy cluster over 6 billion light years away—has been chosen as the European Space Agency’s “picture of the month.”
By capturing extremely distant galaxies, astronomers are essentially looking back in time.
Because light travels at a fixed speed, viewing faraway galaxies means seeing them as they were billions of years ago. The JWST, which started operating in 2022, can detect light from incredibly faint galaxies—some a billion times dimmer than what the human eye can see.
This allows researchers to study galaxies that existed when the universe was still young.
These galaxy groups, also called proto-clusters, are dense regions of space filled with dark matter, hot gas, and large central galaxies.
These environments are crucial to understanding the life cycles of galaxies. The galaxies within them often collide, merge, and evolve in shape and size. In the process, they influence one another and grow into the massive structures we see in the universe today.
Galaxies are not randomly scattered through space. They tend to gather in groups and clusters, connected by a network of filaments that form the so-called cosmic web. Our own Milky Way belongs to a small group called the Local Group, which also includes the Andromeda galaxy and other smaller neighbors.
Gozaliasl explains that galaxies, like people, often form “families.” These groupings help astronomers understand how galaxies interact, how their shapes transform, and how processes like star formation change over time.
Interestingly, galaxies in the early universe appeared more chaotic and were actively forming stars. In contrast, galaxies closer to our time are more structured and have less star-forming activity.
By comparing galaxies across this huge time span, scientists are beginning to piece together a kind of family history of the cosmos. It’s a remarkable window into how the universe—and everything in it—has evolved over billions of years.
