An international team of astronomers has created a computer simulation that can simulate almost the entire universe. This virtual universe is used to better understand cosmic processes. Dutch scientists are also involved in the research.

The simulation runs on a supercomputer in Durham, England, with 30,000 processors. “We cannot simply form a galaxy in the laboratory,” says astronomer Job Schaie of Leiden University, one of the co-researchers. “That’s why we’re building a simulation in which we can operate buttons.”

The computer does not actually recreate all the particles in the universe. The flamingo simulation (the previous, smaller simulation also contains bird names) contains an unprecedented amount of data: 300 billion test particles in a virtual cube with sides ten billion light-years long. In this way, astronomers can recreate most of the universe visible to us from shortly after the Big Bang until long into the future.

Since the Big Bang, the universe has been expanding and most of the matter has accumulated into galaxies filled with stars, planets, and other objects. Astronomers have used computers for decades to understand how these processes work. Previous simulations at this scale have not mimicked all of the matter, Shay explains. Only dark matter and energy are simulated. This makes sense, because those components make up most of the universe, and although they are invisible, they have a significant impact on the processes in the universe.

But visible matter also plays a role in the evolution of galaxies and other cosmic processes. They have also been included in the new simulation. “We can also compare that ordinary matter more easily with what we see in the universe with telescopes,” Shay says.

Example of a simulation from Flamingo’s study of the evolution of a cluster of galaxies:

The program simulated a large number of processes to gain more knowledge about cosmic phenomena. The results were published today in the journal Monthly Notices of the Royal Astronomical Society.

For example, astronomers have investigated a phenomenon for which there is no good explanation yet: the degree of clumping of matter in the universe. This clumping is less than expected according to current theories, according to computer simulations.

Some astronomers believe that massive galactic winds (shock waves emanating from the galaxy) may play a role in reducing the clumping. However, flamingo simulations showed that this effect exists, but is not sufficient to explain the lack of clumping.

Currently, no new simulations are being performed on the scale of almost the entire universe, as Shay knows. He expects to spend several years analyzing the simulations performed so far.

In the future, simulations like Flamingo’s will play an essential role in interpreting the vast amounts of data returned to Earth by new space telescopes, such as the recently launched European EUCLID telescope, the Leiden astronomer predicts. “These types of computer simulations can link theories about our world to observed data. The amount of data is so vast that this would not be possible otherwise.”