It’s the most complete simulation of the universe that humanity has ever built. It stretches a billion light-years across. It’s populated by nearly 2 million galaxies, and 10,000,000,000,000,000 stars, rendered in clusters. Each of them has working gravity and magnetic fields.
Called llustrisTNG, and developed by a cross-collaborative dream team of researchers, this new model of space allows scientists to study how the universe formed and how it will continue to evolve without relying on star charts or telescopes. With llustrisTNG, scientists can see the universe ooze together from the Big Bang to today.
“These simulations will significantly advance our understanding of how galaxies form and evolve over time, and therefore also where stars form and what are the conditions in which stars spend their lives,” says Shy Genel, a contributor from the Flatiron Institute. “Only by understanding galaxy formation as a whole will we be able to understand the history of our own Milky Way galaxy, and even specifically of our own Sun. Also, [these] galaxies allow us to probe into otherwise inaccessible regimes of physics, and so understanding them better puts us on a path towards better understanding the fundamental laws and contents of our universe.”
It’s worth noting that the universe being studied here isn’t literally our own. You won’t be able to find Earth, our solar system, or even the Milky Way. It’s more like a simulated parallel universe, which operates under all of our known laws of physics. That’s extremely difficult to build, Genel explains, because scientists need to model these stellar phenomena with equations even when we have very little understanding of how they work. A good example is black holes, which feature time-bending gravitational pulls and the slow accretion of mass that are difficult to quantify.
The researchers had other concerns with the model’s design–like how to push current computers to the limits of computation to render a literal intergalactic scale, while still maintaining the finite details that are worth studying. One solution was simply that they edited things down a lot. “The simulated universe we created with this project, as large as it is, is still approximately a hundred thousand times smaller than the observable universe!” says Genel. The team also used Germany’s fastest supercomputer, dubbed the Hazel Hen, to run the simulation only twice in total–a process that took two months, but will provide data for scientists to analyze for years to come.
If you’d like to explore more of the IllustrisTNG data, you can get a small taste through its web portal. Truth be told, only astrophysicists will be able to make sense of the entire spectacle. But at least the rest of us can admire the god-sized webs of matter and galactic-scale pyrotechnics. Even if, ultimately, the whole universe is a beautiful simulation–both ours and llustrisTNG’s, too.