MIT-led Lumina simulation maps 2 billion years of cosmic dawn across 1.6 billion light-years
Researchers at MIT, Harvard and other institutions released Lumina, a simulation that follows 2 billion years of cosmic history across 1.6 billion light-years. It models hydrogen and helium reionization together for the first time, showing early stars cleared hydrogen while feeding black holes supplied more energetic radiation for helium. The simulation gives astronomers a larger, more complete framework for comparing theory with telescope observations of the universe's first light.
The simulation, called Lumina, was developed by researchers at MIT, Harvard University and other institutions and published in Monthly Notices of the Royal Astronomical Society. It recreates a cube of the early universe about 500 megaparsecs, or 1.6 billion light-years, across and follows about 2 billion years of cosmic evolution from the era before the first stars to a universe becoming transparent to light. It tracks dark matter, gas, stars and photons, resolving both individual galaxies and large-scale radiation fields.
Lumina reproduces two major changes: hydrogen reionization and helium reionization. Hydrogen reionization began when early stars and galaxies emitted ultraviolet radiation that stripped electrons from neutral hydrogen, clearing the universe's fog. Helium reionization required more energetic photons, and the simulation indicates actively feeding supermassive black holes supplied much of that radiation. The authors describe it as the first simulation to capture both transformations together, in a volume 100 times larger than previous best simulations.
The result matters because the cosmic dark ages, beginning about 380,000 years after the Big Bang, left little direct light for telescopes to see. Lumina provides a physical bridge between the hot early universe and the first galaxies, connecting star formation, black hole growth and radiation transport in one model. Because it is a simulation, its reliability rests on assumed physics, numerical resolution and initial conditions; the researchers are making it available for comparison with telescope observations.
The universe's emergence from darkness shaped the environment in which galaxies, stars and planets later formed. By separating the roles of early stars and black holes in reionizing hydrogen and helium, Lumina gives scientists a clearer map of how radiation altered early space. That matters for astronomy because it gives researchers a benchmark for interpreting faint signals from the earliest galaxies and planning observations of the infant universe.
It helps astronomers understand how the first stars and black holes made the universe transparent, shaping the cosmic environment that later formed galaxies and planets. That gives researchers a clearer framework for reading telescope signals from the early universe.
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- [1]Original source(https://www.sciencedaily.com/releases/2026/11/261110042534.htm)