Watch and hear how galaxies evolve in these new simulations. Video via Royal Astronomical Society.
- A new simulation allows scientists to see and hear the evolution of galaxies. COLIBRE simulations track the growth of the universe from its earliest days to today in unprecedented detail.
- By including cold gas and cosmic dust – Star raw materials – The model more accurately reproduces real galaxies. The simulations agree with observations made by Webb and other telescopes.
- This result shows that the standard cosmological model remains valid. They also explain how galaxies have formed and evolved over billions of years up to the present day.
The Royal Astronomical Society published this original story on April 13, 2026. Edited by EarthSky.
Model how galaxies grow and evolve
Scientists have created the most realistic simulation yet of how galaxies form and change over time. These simulations allow us to see and hear how galaxies evolved in the early universe.
of Royal Astronomical Society Monthly Notices The data show that when key physics are included, standard cosmological models can successfully explain the observed growth of galaxies from the first billion years after the Big Bang to the present day.
Unlike previous simulations, the COLIBRE virtual universe models the cold gas and cosmic dust inside galaxies. That is the raw material from which stars are formed. And this has a big impact on how galaxies appear in telescopes.
By including these previously missing components and using far more computing power than previously possible, the simulation succeeded in reproducing real galaxies. And this is possible both in the present universe and in the early universe witnessed by the James Webb Space Telescope.
Project leader Joop Schaye from Leiden University said:
Much of the gas in real galaxies is cold and dusty, but most previous large-scale simulations have had to ignore this. With COLIBRE, we have finally delivered on these important components.
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digital cold gas and dust particles
According to an international team of researchers, their COLIBRE simulation broke new ground in several ways. Previous simulations artificially prevented the gas inside the galaxy from cooling below about 10,000 degrees Fahrenheit (5,500 degrees Celsius). It is hotter than the surface of the sun. Previously, modeling colder gases was too complex. But observations show that stars form in cold gas. COLIBRE includes the additional physical and chemical processes needed to directly model this cold interstellar gas.
COLIBRE also simulates small dust particles. These particles can have a major impact on galactic gas. Solid particles can help form the hydrogen molecules that dominate a galaxy’s cold gas content. The dust also protects the gas from strong ultraviolet light. And this has a big impact on how galaxies appear in telescopes. Dust absorbs ultraviolet and optical light from stars and re-emits it in the infrared, shaping much of our astronomical observations. By directly modeling dust, COLIBRE opens new ways to compare simulations and real data.
Thanks to advances in algorithms and supercomputing, COLIBRE uses up to 20 times more resolution elements than previous simulations. This allows scientists to simulate larger volumes with more detail and better statistics.
new laboratory
COLIBRE demonstrates that realistic processing of cold gas, dust and outflows caused by stars and black holes is important for understanding the evolution of galaxies, researchers say. This provides a powerful new laboratory for testing theories, interpreting observations, and creating “virtual observations” to see how astronomers analyze real data.
The discovery also shows that standard cosmological models remain consistent with observations of galaxy evolution. These include things that scientists considered challenging, such as clumps of galaxies from the early universe.
Evgenii Chaikin from Leiden University is lead author of several COLIBRE papers and co-author of the main study. Chaikin said:
Some of the early JWST results were thought to cast doubt on standard cosmological models. COLIBRE shows that when key physical processes are more realistically represented, their models match what we see.
some questions remain
Still, not everything is yet solved, such as the mysterious Little Red Dot discovered by Webb. These could possibly be the seeds of supermassive black holes, but COLIBRE did not predict that. Therefore, it is assumed that such a seed already exists. Modeling their formation will require even higher resolution simulations and new physics.
The astronomers ran the simulations using the SWIFT simulation code on the COSMA8 supercomputer at Durham University’s Institute for Computational Cosmology. It is hosted on behalf of the UK’s DiRAC National Facility. The largest simulation required 72 million CPU hours, and the complete model took nearly a decade to develop by an international team across Europe, Australia, and the United States.
Carlos Frenk is Ogden Professor of Fundamental Physics at Durham University’s Institute for Computation and a core member of the COLIBRE team. Frank said:
It’s refreshing to see “galaxies” come out of the computer that look indistinguishable from the real thing and share many of the properties that astronomers measure in real data, including their number, brightness, color, and size.
I like to tease my fellow observers and ask them, “Which galaxy catalog do you think these images came from?”
Most notably, this synthetic universe can be created purely by solving the relevant physical equations within the expanding universe.
Scientists note that it will take years to analyze the data already generated. Most simulations were completed in 2025, but some of the highest resolution simulations are still running. Researchers plan to complete the project by the summer.
See and hear the evolution of galaxies
Beyond traditional data products, the team developed new ways to explore simulation. This includes: sonified video. The video has audio encoded to provide additional physical information. There are also interactive maps that allow users to explore the virtual world.
James Trayford from the University of Portsmouth led the development of COLIBRE’s dust model and the sonification of its visualization. Mr Trayford said:
We’re excited not only about science, but also about creating new ways to explore it. These tools can provide new insights, make our field more accessible, and help build intuition about how galaxies grow and evolve.
Bottom line: See and hear galaxies evolve in new simulations in this video from the Royal Astronomical Society. This simulation helps astronomers track the growth of the universe from the early days of the universe to today.
Source: COLIBRE project: Cosmological hydrodynamic simulation of galaxy formation and evolution
via Royal Astronomical Society
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