Not long ago scientists detected the existence of gravitational waves, the first direct evidence of the Big Bang. Now, thanks to astronomers at MIT and the Harvard-Smithsonian Center for Astrophysics, we now can see what the Big Bang and its aftermath may have looked like.
The results, published in this week’s Nature, were brought to life with Illustris, a computer simulation that visually chronicles the universe’s 14-billion-year life. Actually, it starts “shortly” after the Big Bang, which is really 12 million years after the fact, but in the grand scheme of things that’s just a drop in the bucket. Simulating the creation of the universe is much easier said than done. We’re not just talking about generating pretty pictures here, we’re talking about modeling, in high definition, the formation of galaxies, black holes, stars, planets, matter, and dark matter, as accurately as scientifically possible, while crunched into a matter of minutes. That’s one hell of a task. “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,” says co-author Shy Genel.
It takes a whole lot of computing power, as well as 12 billion pixels, to make such a rendering happen. The team developed Illustris over a period of five years, and the calculations they used in the modeling required the power of 8,000 CPUs operating in parallel for 3 months. Astronomers estimate that on a conventional computer, such calculations would have taken about 2,000 years. The program contains over 100,000 lines of program code and is the first with the ability to render both large-scale events, such as gas distribution, and small-scale ones, such as stars’ chemical signatures.
Still, the simulation isn’t big enough to depict the entire universe. It does much more than any other simulation has ever done, though, displaying a 350 million light-year-wide cube, which shows the formation of 41,000 galaxies, which in the simulation aren’t in the exact places where astronomers see them now.
The goal of the project is to compare what astronomers see via telescope to the computer simulation. That way scientists can test out their various theories about the creation of the universe, seeing as how there’s no lab experiment that can simulate that. So far, comparisons with Hubble Telescope observations indicate both consistencies and inconsistencies.