New Simulation Models 3.4 Billion Galaxies for Euclid Mission

Zurich, Switzerland — The Euclid Consortium has unveiled the most extensive simulation of the universe, called Flagship 2, mapping 3.4 billion galaxies and tracking the gravitational interactions of over 4 trillion particles. This groundbreaking simulation assists the European Space Agency’s (ESA) Euclid mission, which aims to survey the cosmos.

Astrophysicist Joachim Stadel from the University of Zurich developed the algorithm that generated the simulation, utilizing the supercomputer Piz Daint in 2019 when it was among the world’s most powerful supercomputers. Stadel’s work produced an exceptionally detailed virtual model designed to prepare for the analysis of data gathered by the Euclid space telescope, launched in June 2023.

“These simulations are crucial for preparing the analysis of Euclid’s data,” said Julian Adamek, a collaborator on the project. Euclid is expected to scan about one-third of the sky and produce vast quantities of information about the distribution of dark matter and dark energy.

The quantitative data modeling allows scientists to understand the cosmos better and test existing theories. The Flagship 2 simulation incorporates the latest knowledge about the universe’s composition. Stadel noted, “We already see indications of cracks in the standard model,” which suggests that Euclid might uncover unexpected phenomena.

Euclid may also provide insights into dark energy, a force influencing the universe’s expansion. “We can see how the universe expanded at that time and measure whether this constant really remained constant,” Adamek explained. This research could transform our understanding of cosmic history.

The first observational data from Euclid was released in March 2025, with further datasets expected to be published in spring 2026. The mission aims to create a comprehensive cosmic map and may reveal rare cosmic events due to its vast observational scope.