Virtual “universe machines” illuminate the evolution of the Galaxy

By creating millions of virtual universes and comparing them to observations of actual galaxies a UA led research team has made discoveries that present a powerful new approach for studying galaxy formation.

How do galaxies such as our Milky Way come into existence? How do they grow and change over time? The science behind galaxy formation has remained a puzzle for decades, but a University of Arizona-led team of scientists is one step closer to finding answers thanks to supercomputer simulations.

Observing real galaxies in space can only provide snapshots in time so researchers who want to study how galaxies evolve over billions of years have to revert to computer simulations. Traditionally, astronomers have used this approach to invent and test new theories of galaxy formation one by one. A team overcame this hurdle by generating millions of different universes on a supercomputer each of which obeyed different physical theories for how galaxies should form.

challenge fundamental ideas about the role dark matter plays in galaxy formation, how galaxies evolve over time and how they give birth to stars.

On the computer we can create many different universes and compare them to the actual one, and that lets us infer which rules lead to the one we see researcher said.

The study is the first to create self-consistent universes that are such exact replicas of the real one: computer simulations that each represent a sizeable chunk of the actual cosmos, containing 12 million galaxies and spanning the time from 400 million years after the Big Bang to the present day.

Each “Ex-Machina” universe was put through a series of tests to evaluate how similar galaxies appeared in the generated universe compared to the true universe. The universes most similar to our own all had similar underlying physical rules demonstrating a powerful new approach for studying galaxy formation.

The results from the UniverseMachine as the authors call their approach, have helped resolve the long-standing paradox of why galaxies cease to form new stars even when they retain plenty of hydrogen gas the raw material from which stars are forged.

Further Reading: University of arizon

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