Lumina Project Simulates First Two Billion Years of Cosmos at Unprecedented Scale
Researchers at the Center for Astrophysics have used the Frontier supercomputer to run the Lumina simulation, covering a 1.5-billion-light-year cube and modeling hydrogen and helium reionization for the first two billion years after the Big Bang.
Scientists from the Center for Astrophysics, a partnership between Harvard University and the Smithsonian Institution, have completed the Lumina Project, a computer simulation of the early universe that spans the first two billion years after the Big Bang. The model covers a volume roughly equivalent to a cube 1.5 billion light-years on each side, making it larger than any previous early-universe simulation, such as the 2022 Thesan run.
The simulation was executed on the Frontier supercomputer at Oak Ridge National Laboratory, employing about 15,000 of the system’s 37,000 GPUs. It incorporates data from NASA’s James Webb Space Telescope and other observatories to model the interactions of regular matter, dark matter and radiation during the period.
"Lumina follows both hydrogen and helium reionization," said Zier, a researcher involved in the project, noting that the model captures these processes together in a self-consistent framework.
"For the first time, we can follow along as both hydrogen and helium changed into their modern form across such an enormous volume of the universe, while still resolving the galaxies and other luminous objects driving that transformation," said Aaron Smith, an assistant professor of physics at the University of Texas at Dallas and co-author of the study.
The simulation aims to test theoretical predictions about the early cosmos, including the formation of the first stars and galaxies and the reionization of hydrogen and helium. Early results suggest the simulated universe contains fewer massive galaxies than some James Webb observations indicate, and it reproduces small red objects that some researchers associate with black-hole-driven stars.
In addition to its scientific utility, the Lumina Project produces visualizations that illustrate the distribution of gas temperature, metallicity, dark matter density and stellar light across the simulated volume, offering detailed views of early cosmic structures.