Scientists Create HyperMillennium: The Largest Virtual Universe Simulation Ever

A Chinese-led international team has released a cosmological simulation named HyperMillennium, which represents the largest digital recreation of the universe ever produced. The simulation provides researchers with a high-resolution tool to study the evolution of the cosmos and the formation of large-scale structures.

According to a report by China Daily on April 23, 2026, the simulation encompasses a virtual cube with a side length of 12 billion light-years. To achieve this scale, the team utilized 4.2 trillion virtual dark matter particles, creating a computational model that allows scientists to analyze the universe’s development over a span of 10 billion years.

The project employed a technique known as N-body numerical simulation. This method allows the supercomputer to recreate the universe starting from the period immediately following the Big Bang, calculating the effects of gravity step by step to simulate how matter coalesced into the structures observed in the modern universe.

By integrating physical models of galaxy formation into the simulation, the researchers have produced a comprehensive catalog detailing the positions, brightness and other essential characteristics of virtual galaxies. This data allows astronomers to rewind time to observe the specific processes that led to the creation of galaxies and other cosmic features.

The technical scale of HyperMillennium provides critical theoretical support for the study of dark matter and dark energy, two of the most elusive components of the universe. By comparing the simulated data with actual astronomical observations, scientists can better understand the laws governing cosmic expansion and the distribution of mass.

Beyond theoretical research, the simulation is designed to support new-generation galaxy survey programs. Specifically, the data provides a framework for the European Space Agency’s Euclid mission and the China Space Station Telescope, helping these projects interpret the vast amounts of data they collect from the actual sky.

The simulation was completed with high force resolution and time accuracy and also made a breakthrough in computational scale.

China Daily

The ability to simulate 4.2 trillion particles across such a vast distance marks a significant leap in computational astrophysics. This level of resolution is necessary to capture both the massive cosmic webs that span the universe and the smaller, denser regions where individual galaxies form.

The resulting digital universe serves as a laboratory where hypotheses about the early universe can be tested. Researchers can adjust variables within the N-body simulation to see how different concentrations of dark matter or different rates of expansion would alter the resulting structure of the cosmos.