DATE2025.11.21 #News
Realizing a 300-Billion-Particle Simulation of the Milky Way with AI and the Supercomputer Fugaku
-A High-Resolution Model Resolving Individual Stars to Uncover Galactic Evolution-
Summary
An international research team led by Special Postdoctoral Researcher Keiya Hirashima of the RIKEN Center for Mathematical Science; Associate Professor Michiko S. Fujii and Researcher Naoto Harada of the Graduate School of Science, The University of Tokyo; Associate Professor Takayuki R. Saitoh and Professor Junichiro Makino of the Graduate School of Science, Kobe University; and Associate Professor Kohji Yoshikawa of the Center for Computational Sciences, University of Tsukuba, has achieved the world’s highest-resolution simulation of the Milky Way galaxy. By employing artificial intelligence (AI) together with the full system of the supercomputer Fugaku (approximately 150,000 nodes), the team simulated the entire galaxy using 30 billion particles representing stars, interstellar gas, and other components—resolving the Milky Way down to individual stars.
The results are expected to advance our understanding of the spiral-arm structure of the Milky Way—arms that wind outward from the galactic center in disk galaxies—as well as the circulation of chemical elements within the galaxy and the origins of the materials that eventually formed the solar system and life.
To overcome the computational bottleneck arising from the rapid changes immediately after supernova explosions, the researchers developed a new galaxy-simulation code, ASURA-FDPS-ML, which integrates an AI-based surrogate model for fast prediction, the general-purpose high-performance particle-simulation library FDPS, and the architecture-adaptive optimization toolkit PIKG. As a result, they achieved high parallel efficiency not only on Fugaku but also on the GPU-equipped supercomputer Miyabi (approximately 1,000 nodes). This accomplishment marks the world’s first successful Milky Way–sized simulation resolved down to every individual star.
This research was presented on November 20 at the International Conference for High Performance Computing, Networking, Storage, and Analysis (SC25) and published in its proceedings.
Figure：Conceptual diagram of the developed galaxy simulation code “ASURA-FDPS-ML”
Links
RIKEN, Kobe University, University of Tsukuba
Presentation Information
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Proceedings SC'25: Proceedings of The International Conference for High Performance Computing, Networking, Storage, and AnalysisTitle The First Star-by-star N-body/Hydrodynamics Simulation of Our Galaxy Coupling with a Surrogate Model
TitleAuthors Keiya Hirashima, Michiko S. Fujii, Takayuki R. Saitoh, Naoto Harada, Kentaro Nomura, Kohji Yoshikawa, Yutaka Hirai, Tetsuro Asano, Kana Moriwaki, Masaki Iwasawa, Takashi Okamoto, Junichiro Makino