Wednesday , May 18 2022

Scientists simulate millions of universes on a supercomputer to study the formation of galaxies


Through the mirror: To better understand how galaxies actually form, we need to be able to observe their formation and growth over billions of years. Instead of a time machine, scientists at the University of Arizona use a supercomputer to simulate millions of universes and galaxies.

Scientists have studied the formation of galaxies using state-of-the-art technology for decades, yet we have barely scratched the surface of understanding exactly how these massive bodies grow, evolve and behave.

It's a matter of scale and time, really: they are so huge and exist for so long that our observations give a snapshot.

Peter Behrozi, an assistant at the UA Steward's Observatory, said simulating a galaxy requires a 10th to 48th computation operation. "All the computers on Earth combined could not do this for a hundred years. In order to simulate a single galaxy, let alone 12 million, we had to do it differently, "he said.

As such, each simulated universe is coded to obey different physical theories about how galaxies should form. For a period of three weeks, the Ocelot supercomputer of high-quality United States clusters of clusters was breaking numbers, processing data for more than eight million simulated universes and 12 million galaxies extending from about 400 million years after the Big Bang.

The results have helped scientists understand why galaxies stop forming new stars, even when they have enough hydrogen gas to do so.

"Going back to the universe earlier and earlier, we would expect dark matter to be denser and therefore gas to become hotter and hotter. It's bad for star formation, so we thought a lot of galaxies in the early universe had to stop forming stars for a long time, "Behrosi said. "But we found the opposite: galaxies of a size are more likely to form stars at a higher speed, contrary to expectations."

The team documentation on the subject, UNIVERSEMACHINE: The correlation between the growth of the galaxy and the halo of dark matter of z = 0-10, is available online if you want to dig deeper.

Mast Credit: Spiral Galaxy by Alex Mitt. Star Trek by Christina Siou.

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