For all the scientific advancements made in the last few centuries, many parts of the universe, including stories of its origin and early days, remain a mystery for the human imagination. NASA’s James Webb Space Telescope is only one among many of the powerful observatories that have helped create models of what the earliest galaxies might have looked like. The latest supercomputed simulations are simply the latest addition to this bundle.
Given their credibility in filling many of our knowledge gaps, a team of international researchers has managed to successfully develop one of the most detailed models of the universe yet as per a recent study published in the scientific journal Monthly Notices of the Royal Astronomical Society.
Titled ‘Lumina’, the new simulation recreates a pivotal yet enigmatic phase of transformation by depicting how the first stars and black holes drove reionization. Soon after the big bang, ultraviolet radiation from these early light sources stripped electrons from hydrogen atoms, the most common element in space, allowing light to travel farther and changing how galaxies were formed.
What ‘Lumina’ brings to the table
Light's nature of taking ample time to travel through space has allowed powerful telescopes to capture galaxies as they were billions of years ago. This technical ability feeds the curiosity of astronomers eager to decipher how the universe came to be into its current form. Large models like Lumina fuel such curiosity by allowing astronomers to study long stretches of cosmic history on similarly large scales.
As per lead author Oliver Zier, a postdoctoral research fellow at the Institute for Theory and Computation at the Center for Astrophysics, Harvard & Smithsonian, in Cambridge, Massachusetts, the Lumina is capable of covering more than 100 times as much space as earlier simulations.
{{/usCountry}}As per lead author Oliver Zier, a postdoctoral research fellow at the Institute for Theory and Computation at the Center for Astrophysics, Harvard & Smithsonian, in Cambridge, Massachusetts, the Lumina is capable of covering more than 100 times as much space as earlier simulations.
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“We have a cosmological volume where you can see this cosmic web, how galaxies are clustered. At the same time, we resolve individual galaxies,” Zier told CNN, referring to the simulation’s ability to capture the vastness as well as the intricate details of space.
In addition, the Lumina can be compared with observations from telescopes to test ideas and allow scientists to check if their theories hold up. Zier, however, feels differently on the matter of testing ideas. “But it’s actually more interesting if they don’t agree, because then that means that there’s something missing in our model, and that might give hints to missing physics,” he remarks.
Developing the ‘Lumina’
For the first time in human history, changes in both hydrogen and helium, the second most common element in space, can be seen simultaneously to record the transformation of the early cosmos in a single simulation via the Lumina.
“Lumina is a really impressive technical achievement,” Julian Muñoz, an assistant professor of astronomy at the University of Texas at Austin, told CNN. “Simulations of how the first galaxies form and ionize the early universe are expensive, so they typically only follow fairly small patches of the cosmos for a limited time. Lumina is both bigger in size and runs for a longer cosmic time than past detailed simulations of this kind." Muñoz, however, was not involved in the new study.
Due to disparities in the evolution of the early universe, the Lumina allows researchers to simultaneously study how different regions shifted over time. The varied movement of dark matter and ordinary matter through space can also be studied.
Beyond functionality, the feat of creating the ‘Lumina’ in and of itself is no less than a scientific marvel. More than 15,000 graphics processing units of Frontier, a supercomputer at Oak Ridge National Laboratory in Tennessee, took nearly three years of computing power to create the massive model. As per NASA, the Lumina spans roughly 1.5 billion light-years across in each direction in comparison to the Milky Way which is about 100,000 light-years wide.
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Though the Lumina has not yet been released fully for the public, videos of the simulation allow one to zoom in on individual galaxies only to then pull back and compare them against the rest of the cosmos, giving a suggestive idea of how vast the space is. “Even though Lumina is very big, it’s still only a very small part of the universe,” Zier adds.