There is a virtual universe online, and it is accessible to all

Uchuu is the largest simulation of the history of the universe ever made. It is accessible to everyone and is already in use at several universities: it allows us to understand the life of galaxies.

It is called Uchuu, which means "deep space" in Japanese, and it is the largest and most realistic simulation ever created of the universe as it is today. Illustrated in the latest issue of the Royal Astronomical Journal, Tomoaki Ishiyama's simulation is already helping astronomical research around the world.

Uchuu: 13 billion years of history

The dimensions of the immense simulation, whose code was written by Professor Ishiyama but whose development has involved researchers from halfway around the world, are not only physical, covering for the first time in history a distance of more than 9 billion light years from one end to the other.

Uchuu was developed thanks to ATERUI II, the most powerful computer in use in astronomical sciences active since 2018, in order to study the evolution of concentrations of dark matter from which galaxies originate.

It is a simulation focused on large-scale objects, which is why individual planets are not detailed, and in particular on their evolution over time. In this case, billions of years of history are needed to study how galaxies form. Uchuu covers as much as 13.8 billion of the universe's history.

Uchuu is already in use by students and institutions around the world: Andalusia Astrophysics Institute student Julia F. Ereza has already used it to analyze the large-scale structure of the universe.

"Uchuu is like a time machine: you can go forward, backward, stop time, zoom in on a single galaxy or move away to view the entire cluster," says the student, "we can see what is really happening at every moment and in every place in the universe, from the earliest days to the present." Uchuu has only been unveiled to the world for a few days, but it's already a fundamental tool for studying the cosmos.

The Universe for Everyone

Uchuu is a simulation that encompasses more than 2 trillion particles in a 9-billion-light-year computational cube. All of Uchuu's data has been made available in a 100 terabyte catalog, which of course no home computer would be able to download. Therefore, the largest simulation of the universe ever created has been made available to the world's public via a cloud, hosted at the Andalusian institution of Eereza.

Of course, to productively access the infinity of the simulated universe, you need some basic skills: you need to know the standard cosmological model, for starters.

But Ishiyama's idea is truly inclusive, at least on a technological level: "to produce Uchuu we used all 40,200 available processors, in exclusive use for 48 hours a day. We consumed twenty million hours of supercomputer work," Ishiyama explains, "and generated the equivalent of 894,784,853 photos from a 12-megapixel cell phone."

Future versions of Uchuu will feature internal simulations, for example related to the formation of specific galaxies and active galactic nuclei, that will allow us to discover much about how the universe originated and its future.