Lumina simulation recreates the universe's first 2 billion years

Researchers at the Harvard-Smithsonian Center for Astrophysics have developed Lumina, a massive cosmological radiation-hydrodynamics simulation that models the first two billion years of the universe. Spanning a cubical region of approximately 1.5 to 1.6 billion light-years, the simulation covers a volume more than 100 times larger than previous comparable models.

Lumina tracks the complex interactions between dark matter, ordinary matter, and radiation. It is the first simulation capable of capturing both hydrogen and helium reionization in real time, suggesting that early stars drove hydrogen reionization while energetic supermassive black holes likely drove helium reionization. This provides a critical theoretical framework for astronomers to compare against real-world data from the James Webb Space Telescope and the upcoming Nancy Grace Roman Space Telescope.

To achieve this level of detail, the team utilized the Frontier supercomputer at Oak Ridge National Laboratory in Tennessee, harnessing more than 15,000 graphics processing units (GPUs).