Move over, Matrix—astronomers have done you one better, creating what they call the first realistic “virtual universe” using a computer simulation.
Before, “no single simulation was able to reproduce the universe on both large and small scales” at once, said astronomer Mark Vogelsberger, a collaborator in the work. Called Illustris, it mimics a period of 13 billion years, almost the whole estimated age of the universe.
Previous simulations were hampered by lack of computing power and the complexities of physics, scientists said. As a result they were limited in detail, or in the space covered. They had trouble mimicking interactions—thought to strongly affect how the universe developed—between star formation, stellar explosions, and giant black holes.
Illustris assumes the presence of “dark matter,” material believed by most astronomers to be an unseen ingredient of the universe though it is detected only through its gravity.
The simulation cube contains 12 billion pixels, or resolution points. The team dedicated five years to developing the program. A simulation run-through took three months, using 8,000 computer processors running together—an average desktop computer would have taken over 2,000 years to do it.
The digital re-enactment “begins” when the universe was about a thousandth of its current estimated age.
When astronomers ran it, by the time it reached “present,” they counted more than 41,000 galaxies in the cube. There was a realistic mix of galaxy types, including spiral galaxies like our Milky Way, they said. It also recreated large-scale structures like galaxy clusters and so-called “bubbles” and “voids” of a cosmic “web,” and, on a smaller scale, the chemistries of individual galaxies.
Since light travels at a fixed speed, the farther away astronomers look, the farther back in time they can see. A galaxy one billion light-years away is seen as it was a billion years ago. Telescopes can give us views of the early universe by looking further out, but can’t show stages in one galaxy’s evolution.
With Illustris, “we can go forward and backward in time. We can pause… and zoom into a single galaxy or galaxy cluster to see what’s really going on,” said study co-author Shy Genel of the Center for Astrophysics. It’s “like a time machine.”
The team is releasing a high-definition video, which morphs between different components of the simulation to highlight various layers. They’re also releasing several smaller videos and images at http://www.illustris-project.org. The results are reported in the May 8 issue of the journal Nature, with Vogelsberger, of the Massachusetts Institute of Technology/Harvard-Smithsonian Center for Astrophysics, as lead author.
Source : http://www.world-science.net/