Researchers have released Lumina, the largest cosmological radiation-hydrodynamics simulation ever produced. The model maps the universe’s first two billion years across half a trillion elements to show how the first stars cleared away the cosmic fog.
Lumina Recreates Cosmic Dawn Across Half a Trillion Elements
The calculation used approximately 15,000 graphics processing units. Researchers used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory.
That hardware supported a virtual universe spanning a cube roughly 1.6 billion light-years wide, or 500 megaparsecs. The simulation tracks half a trillion individual elements, including dark matter particles and gas cells. It delivers roughly 30 times higher resolution than IllustrisTNG, a predecessor developed by members of the same research team.
Radiation Transforms the Universe During Hydrogen Reionization
In this era, a dense fog of neutral hydrogen blanketed space and blocked out the light of the earliest stars. The simulation begins roughly 45 million years after the Big Bang during the cosmic dark age. Lumina traces how matter clumped together under gravity to form the first galaxies, which then unleashed radiation that transformed the universe.
Over the two billion years of simulated cosmic time, the program catalogs a large portion of the 13.8 billion-year history of our universe and captures two monumental transformations. Hydrogen reionization occurred when ultraviolet light from young stars stripped electrons from neutral hydrogen, lifting the cosmic veil and allowing light to travel freely.
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.
Researcher, via Science Daily
Simulated Evolution Links to Modern Space Telescopes
The research team published their findings in the journal Monthly Notices of the Royal Astronomical Society. The study’s MIT co-authors include Teodora-Elena Bluichi alongside Xuejian (Jacob) Shen. Additional authors include first author Oliver Zier, Rongrong Liu, Sonja Koehler, and Lars Hernquist of the Harvard and Smithsonian Center for Astrophysics; Aaron Smith of the University of Texas at Dallas; Rahul Kannan of York University in Canada; and Volker Springel and Rüdiger Pakmor of the Max Planck Institute for Astrophysics in Germany.
By making the simulation publicly available, the scientists aim to give astronomers a benchmark to evaluate observations from instruments like the James Webb Space Telescope and the Nancy Roman Space Telescope. Shen notes that one of Lumina’s major advantages is its sheer size.
Other simulations cannot zoom in as far as this
, he noted, pointing out that the disparity between the smallest and largest scales simulated surpasses any previous model. The simulation tracks radiation as it travels out from stars through the universe until it ionizes neutral hydrogen.
Lead author Oliver Zier, a former postdoctoral researcher and computational astrophysicist at MIT who is now at Harvard University, noted that translating theoretical models into detailed predictions was essential for interpreting high-powered telescope data.