This new simulation of the evolution of the universe since the Big Bang is the most accurate yet. Like previous visualizations, Illustris can recreate the cosmic web of galaxies -- but this computer simulation also includes mixed populations of spiral and elliptical galaxies; it includes large-scale structures like galaxy clusters, bubbles, and voids of the cosmic web, as well as small-scale features, such as the chemistry of galaxies and predictions of gas and metal content.
"Our computer program accounts for the laws of nature -- gravity, the formation of supernovae, black holes -- and then evolves the universe until the present," Shy Genel of the Harvard-Smithsonian Center for Astrophysics tells Popular Mechanics.
In this realistic virtual universe, Genel, MIT’s Mark Vogelsberger, and colleagues, capture the universe 12 million years after the Big Bang and traces 13 billion years of cosmic evolution. Thanks to rapid advances in computer power, they were able to simultaneously model the evolution of different components of galaxy formation, including that of baryons (visible matter) and dark matter. "Until now, no single simulation was able to reproduce the universe on both large and small scales simultaneously," Vogelsberger says in a press release.
The picture above is centered on the most massive cluster, 15 Mpc/h deep. You can see dark matter density (left) transitioning to gas density (right). Pictured here, same massive cluster, with dark matter density overlaid on the gas velocity field.
A 5-year endeavor, Illustris includes both normal matter and dark matter using 12 billion 3-D "pixels" -- or resolution elements. The actual calculations took 3 months of run time, using a total of 8,000 CPUs running in tandem. If they just used an average desktop, for comparison's sake, the calculations would have taken at least 2,000 years to complete. When the simulation reached present day, the team counted more than 41,000 galaxies in the cube of simulated space (350 million light-years on a side).
Here, you can see the stellar light distribution of the most massive cluster.
"Illustris is like a time machine. We can go forward and backward in time. We can pause the simulation and zoom into a single galaxy or galaxy cluster to see what's really going on," Genel explains.
Here's a dark matter annihilation map.
The work was published in Nature this week.
Images: Illustris Collaboration
Video: Nature Video