Chinese team builds world's largest virtual universe

About six weeks ago, researchers at the University of Geneva announced that they had simulated the formation of our universe using a large supercomputer. About 25 billion virtual galaxies were generated from two trillion digital particles.

Now, however, Chinese researchers have smashed their record - creating a universe of their own with a whopping ten trillion digital particles - five times as many as in the previous experiment.

The goal of both experiments is to figure out how our real Universe came to be. Since computers were first invented, physicists have been using them to create these simulated universes and study how they develop over time - from the Big Bang, to the present day, to an eventual end.

From scratch

These simulations are known as N-body simulations, where the N refers to the number of particles. In the 1970s, N was about a thousand. Today, it's 10 trillion, thanks to advances in computer power over that time.

The Chinese team, based at the Chinese Academy of Sciences in Beijing, used the Sunway TaihuLight supercomputer - currently the most powerful in the world - for their simulation. The team had access to 10 million CPU cores, each able to carry out instructions independently.

However, the computer's unique architecture meant that the team had to write almost all of the software from scratch, which they described as a very labour-intensive task.

Very young stage

When it was finally run, the team reported no errors - but the largest ever virtual universe created by humans had to be turned off after just an hour because someone else had booked time on the machine.

"We just got to the point of tens of millions years after the Big Bang. It was still a very young stage for the universe," said Gao Liang, chair of the computational cosmology group at China's National Astronomical Observatories, who built the simulation.

"Most galaxies were not even born."