“In the szczytowym momencie obliczenia łączą moc odpowiadającą ponad 100 tys. rdzeni CPU i około 15 tys. układów GPU,” Xuejian (Jacob) Shen said.
The project maps a region roughly 1,6 mld lat świetlnych wide and tracks matter evolution over 2 mld lat. This timeframe captures the era when the universe emerged from the cosmic dark ages, allowing the first stars and galaxies to illuminate space.
The simulation traces the aftermath of the Big Bang, starting about 45 million years after the cosmic origin. During this epoch, hot primordial plasma expanded and cooled until electrons combined with atomic nuclei to form neutral hydrogen.
The Lumina software builds on the earlier IllustrisTNG simulation by incorporating a radiation transport model. This addition allows researchers to calculate how ultraviolet light and other radiation move through space and interact with surrounding matter.
The virtual model contains roughly half a trillion individual elements, including dark matter particles and gas cells. It delivers roughly 30 times higher resolution than IllustrisTNG while covering an area one hundred times larger by volume.
Running these calculations required the Frontier supercomputer at Oak Ridge National Laboratory in Tennessee. Shen explained that managing the communication between thousands of processors while processing trillions of interacting data points represents a major engineering achievement.
The simulation tracks both dark matter evolution and radiation dispersal across extreme scales. At high magnification, gas falls into dark matter clusters where the first galaxies and stars take shape.
Lumina simultaneously captures two critical transitions: hydrogen reionization and helium reionization. Ultraviolet light from early stars and galaxies drove hydrogen reionization by stripping electrons from hydrogen atoms.
Significantly more energetic radiation was required to drive helium reionization. The simulation results indicate that actively feeding supermassive black holes powered that second process.
“In other symulacje nie potrafią dokonać aż takiego zbliżenia,” Vogelsberger said, noting that the scale span exceeds any previous project.
Lumina builds upon technology from the earlier IllustrisTNG simulation, which was also co-developed by researchers at MIT. The team modified that software by adding a radiation transport model to track ultraviolet light movement.
The calculations were performed on the Frontier supercomputer located at Oak Ridge National Laboratory in Tennessee, utilizing power equivalent to more than 100 tys. rdzeni CPU and roughly 15 tys. układów GPU.
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