Illustris simulation
May 8, 2014

Researchers Create The Most Complete Simulation Of How The Universe Was Formed

redOrbit Staff & Wire Reports - Your Universe Online

Researchers at MIT and Harvard have devised the most accurate model to date of how our universe first took shape.

Dubbed Illustris, the new virtual cosmos covers the 13 billion-year evolution of the universe beginning just 12 million years after the Big Bang. It includes details never before achieved in a simulation, and accurately portrays the distribution and composition of numerous types of galaxies.

"Until now, no single simulation was able to reproduce the universe on both large and small scales simultaneously," said MIT astrophysicist Mark Vogelsberger, who led the team that created the simulation, during an interview with the MIT/Harvard-Smithsonian Center for Astrophysics.

The computer model shows how the very first galaxies formed around masses of an invisible, nebulous substance known as dark matter. The researchers attribute their success to advanced computing power, and said the model is so complex that it would take a conventional desktop computer 2,000 years just to run the simulation a single time.

To create Illustris, the researchers factored in not only the laws of physics, but also the way in which stars evolve and gases cool, along with the explosive energy of supernovae, how heavy chemical elements are produced and the way gas accretes around supermassive black holes.

A seven-minute video representing data from the Illustris simulation portrays blue ephemera that begins to clump together and form a cosmic web-like structure that is actually a network of dark matter, drawn together by gravity. Pink areas are shown where the dark matter is its most dense.

As the video proceeds, the images transform from the blue and pinks of dark matter into the greens, reds and whites of the gas field. At nearly 5 billion years after the big bang, explosions appear that are feedback from supermassive black holes that scientists believe are at the center of nearly all the nearby galaxies.

"Black holes do swallow material, but when they are doing that they also release a lot of energy that can lead to large-scale outflows," said Paul Torrey, a Harvard graduate student in astronomy who helped develop Illustris.

"The presence of these black holes substantially alters galaxy formation,” he said.

The researchers said the simulation does not begin until 12 million years after the Big Bang because the universe lacked structure before that time.

They also note that Illustris is not a precise replica of the universe, but rather a smaller one about 350 million light-years across.

And while the 40,000 galaxies the model created share the same properties as those in our universe, they are not in the exact locations as the galaxies we see in telescopes.

In addition to the simulation video, the Illustris team has created a website that provides additional access to the model, including an Illustris explorer that allows viewers to zoom in on different parts of the mock universe.

"Watching the video is like flying through the universe way faster than the speed of light and watching galaxies as they are assembling," Torrey said. However, he added, "our work here has only just begun.”

"Now that we have this model, our job is to understand it in as much detail as possible."

The work is described in Thursday’s issue of the journal Nature.