Euclid Consortium Releases Largest Simulation of the Universe

GENEVA, Switzerland — The Euclid Consortium unveiled the world’s largest and most detailed computer simulation of the universe, known as Flagship 2, on September 27, 2025. This groundbreaking digital model maps 3.4 billion galaxies and tracks the gravitational interactions of more than 4 trillion particles.

Astrophysicist Joachim Stadel from the University of Zurich (UZH) led the development of the simulation using the supercomputer Piz Daint in 2019. The simulation serves as a virtual universe, essential for analyzing data collected by the Euclid space telescope, launched by the European Space Agency in July 2023.

“These simulations are crucial for preparing the analysis of Euclid’s data,” said Julian Adamek, an astrophysicist at UZH and collaborator on the project. Euclid is currently mapping billions of galaxies to study dark energy and dark matter, which together comprise nearly 95% of the universe. The spacecraft aims to scan roughly one-third of the night sky, collecting vast quantities of data.

Stadel noted that while Flagship 2 runs on existing knowledge about the universe’s structure, surprises could emerge. “We already see indications of cracks in the standard model,” he explained, hinting at potential revelations following Euclid’s findings.

The team is particularly interested in understanding dark energy, a mysterious force driving the accelerated expansion of the universe. Euclid’s observations will examine this phenomenon up to 10 billion years into the past. “We can see how the universe expanded at that time and measure whether this constant really remained constant,” said Adamek.

The first observational data from the Euclid mission was released in March 2025, with additional data expected in spring 2026.