Small Galaxies Might Breathe Like Living Things

By Space.Fan Editorial DeskOctober 1, 2026 at 8:02 AM UTC

New research suggests that small galaxies grow and shrink as they blast out gas and pull it back in during cycles of star formation.

Image · Space.Fan

The Drop

Astronomers have long wondered how small galaxies change over time. Many think these galaxies go through a process called a breathing mode. In this cycle, the galaxy acts like a lung. When s are born and die, they create powerful energy that pushes gas out of the galaxy. Later, that gas cools down and falls back inside, which helps trigger the birth of even more s. This movement changes the galaxy's size and how fast it makes new s. To test this idea, researchers looked at 103 small, -forming galaxies. They used ground-based telescopes to measure the speed of the gas inside these systems by studying light waves emitted by the galaxies. They then compared this real-world data to high-tech computer models known as FIRE-2 simulations. These simulations are designed to mimic how s, gas, and dark matter interact in a growing galaxy. The team found a strong connection between how fast gas moves inside a galaxy and how quickly it creates new s. This link matches what the computer models predicted. The results suggest that these galaxies are indeed dynamic, constantly shifting their shape and contents as they go through cycles of activity.

Why It Matters

This discovery helps scientists understand the life cycle of small galaxies. If these galaxies are truly breathing, it explains why they have different amounts of dark matter than older, larger galaxies. It shows that s themselves are not just passive objects, but active engines that can reshape the entire structure of their home galaxy from the inside out.

The Catch

While the results are promising, the real-world galaxies did not show as perfect a pattern as the computer simulations did. The computer models predicted some slow-moving, quiet galaxies that were not as easy to find in the real data. This could mean that the simulation still needs to be adjusted to perfectly match the complex nature of the actual universe, or that we simply need to observe more galaxies to find the missing pieces.

Put That in Perspective

Scientists are eager to look at even larger groups of galaxies to see if this breathing pattern holds up everywhere. By comparing these findings with better telescope images, they hope to confirm that these tiny, active galaxies are the building blocks for how larger galaxies form over billions of years.

Source October 1, 2026

Yifei Luo, Joseph Wick, Alexie Leauthaud, Andrew Wetzel, Tucker Jones, Erin Kado-Fong, Song Huang, Xinjun Chen, Conghao Zhou, Jiaxuan Li

Lawrence Berkeley National Laboratory, University of California Santa Cruz, University of California Davis, Yale Center for Astronomy and Astrophysics, Tsinghua University, University of Missouri, Princeton University·The Astrophysical Journal·10.3847/1538-4357/aea28f