first_img We’re still not sure exactly how our Milky Way formed.But scientists at the University of Arizona (UA) are one step closer to finding out, thanks to supercomputer simulations.Traditional observations of real galaxies provide only snapshots; astronomers must invent and test theories of individual evolution.To overcome these hurdles, a UA-led team used a supercomputer to generate millions of different universes, each of which obey different physical hypotheses for how galaxies should form.“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,” study author Peter Behroozi, an assistant professor at the UA Steward Observatory, said in a statement.Each “Ex-Machina” computer-simulated universe contains 12 million galaxies and spans the time from 400 million years after the Big Bang to present day.Results from the so-called “Universe Machine” 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 celestial bodies are born.“As we go back earlier and earlier in the universe, we would expect the dark matter to be denser, and therefore the gas to be getting hotter and hotter,” Behroozi said. “This is bad for star formation, so we had thought that many galaxies in the early universe should have stopped forming stars a long time ago.“But we found the opposite: galaxies of a given size were more likely to form stars at a higher rate, contrary to the expectation,” he added.The study, published recently in the journal Monthly Notices of the Royal Astronomical Society, is co-authored by Risa Wechsler at Stanford University, Andrew Hearin at Argonne National Laboratory, and Charlie Conroy at Harvard University.The team utilized computing resources at NASA Ames Research Center and the Leibniz-Rechenzentrum in Germany, as well as the Ocelote supercomputer at the UA High Performance Computing cluster.Two-thousand processors crunched data simultaneously for three weeks.Moving forward, Behroozi & Co. plan to expand the UniverseMachine to include the morphology of individual galaxies and how their shapes evolve over time.Watch This Next: Where Are the Lost Apollo 11 Moon Landing Tapes?More on Teach AI To Spot Far-Away Galaxy ClustersMilky Way ‘Ate’ a Nearby Dwarf Galaxy 10 Billion Years AgoHP Supercomputer Headed to Mars on SpaceX Rocket Stay on target ‘World’s Most Powerful Computer’ Coming to US in 2021HP Supercomputer Headed to Mars on SpaceX Rocket last_img read more