Researchers at the Harvard & Smithsonian Center for Astrophysics have introduced Lumina, one of the largest, most detailed simulations of the early universe ever created.
Capable of modeling the first 2 billion years after the Big Bang, Lumina will help astronomers make sense of the increasingly complex data collected by the James Webb Space Telescope (JWST) and the newly installed Nancy Grace Roman Space Telescope (Roman).
“By comparing observations from JWST, Roman and other telescopes with Lumina’s predictions, astronomers can determine whether their understanding of the laws governing the universe remains accurate or whether new discoveries may require them to rethink existing theories,” the research team explained.
Lumina Compares Simulations of the Early Universe to Real-World Observations
According to that same statement, astronomers have spent centuries building increasingly sophisticated models of the universe to explain the formation of stars, galaxies, and other cosmic structures. In recent decades, increasingly powerful computers have enabled more precise models, helping scientists unravel the early universe’s mysteries.
However, with the advent of Roman and JWST, scientists are beginning to reach the limits of current models, leaving them without a set of viable predictions to compare against real-world telescopic readings.
Oliver Zier, an ITC Fellow at the Harvard & Smithsonian Center for Astrophysics and lead author of a study detailing Lumina’s development, said these observatories have opened up a new window into the early universe, making more accurate models more pressing than ever.
“With JWST, the early universe has become an exciting new frontier in astrophysics,” Zier explained. “To understand what we are seeing with this telescope, we need to translate our theories into detailed predictions.”
Frontier Supercomputer Offers 100 Times More Volume of Simulated Space
To create Lumina, Zier and colleagues used more than 15,000 independent graphics processing units running on Frontier, a supercomputer located at Oak Ridge National Laboratory in Tennessee. Because Frontier is one of the fastest supercomputers in the world, the team said that Lumina covers more than 100 times the volume of space covered by previous “comparable” simulations.
This immense coverage allowed the team to model a massive, cube-shaped area of space roughly 1.5 billion light-years on each side. For comparison, the team said this area matches the region of space the most powerful modern telescopes can observe “while maintaining the level of detail needed to study the formation of galaxies, stars and black holes.”
Lumina’s modeling power allows it to recreate the interaction between ordinary matter, dark matter, and cosmic radiation during those first critical 2 billion years of the universe’s formation. This included tracing the emergence of the universe’s first galaxies and how they transformed the “vast regions” of gas between them.
“This type of simulation models how the universe’s fundamental ingredients, including gas, dark matter and light, interact to form stars and galaxies,” they explained.
The study authors said that Lumina is also the first simulation tool to capture the mysterious process of helium reionization as it occurred “while allowing its effects to immediately influence the evolving universe within the model.”
“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,” explained Aaron Smith, an assistant professor of physics at the University of Texas at Dallas and an author on the paper.
Watching Predictions “Come to Life”
When discussing Lumina, the research team said finishing the largest cosmological radiation-hydrodynamics simulation ever created and seeing it put to the test was a special moment.
“After several years of work, with plenty of ups and downs, it is incredibly rewarding to see the simulation results and watch our predictions come to life in video,” Zier said.
Smith agreed, noting that the team feels “incredibly fortunate to be building simulations like Lumina.”
Moving forward, the Harvard Smithsonian team said the tool will allow future studies to “investigate how gases move between galaxies, how radiation from the Big Bang shaped cosmic evolution and how regions of intense star formation developed over time.”
The study was published in Monthly Notices of the Royal Astronomical Society.
Christopher Plain has spent the last six years as Associate News Editor and Head Science Reporter at The Debrief. Follow and connect with him on X, learn about his novels at plainfiction.com, or email him at christopher@thedebrief.org.