A Computing Behemoth has recently produced the most extensive cosmic simulation to date.
Last month, a group of scientists put the world's swiftest supercomputer, named Frontier, to work on a significant question: the character of atomic and dark matter in the universe.
Frontier, a renowned exascale-class supercomputer, was employed by this team to perform the largest astrophysical simulation of the universe ever conducted. The simulation's size mirrors surveys taken by large telescope observatories, a feat hitherto unattainable. These calculations shape the framework for cosmological simulations, covering everything from observable matter to the invisible substance that interacts gravitationally with ordinary matter, but cannot be seen.
What calculations did Frontier make?
Capable of executing a quintillion (10^18) calculations per second, Frontier is an impressive machine fit for the herculean task of simulating the physics and evolution of both known and unknown universes.
"To grasp what the universe is up to, we need to simulate gravity as well as other physics, including hot gas, and the formation of stars, black holes, and galaxies," mentioned Salman Habib, the divisional head for computational sciences at Argonne National Laboratory, in a statement by Oak Ridge National Laboratory. "The astrophysical ‘melting pot’, if you will."
While known matter - black holes, molecular clouds, planets, and moons - makes up merely 5% of the universe's total content, as per CERN, a more substantial portion is inferred by implementing gravitational effects on visible matter. This invisible portion is commonly referred to as dark matter, a term used to encompass various particles and objects, said to account for approximately 27% of the universe's overall composition. The remaining 68% of the universe is attributed to dark energy, responsible for the universe's accelerated expansion rate.
How does Frontier change our perception of the universe?
"If we were to simulate a substantial portion of the universe observed by one of the major telescopes, such as the Rubin Observatory in Chile, you're looking at analyzing vast stretches of time—billions of years of expansion," explained Habib. "Until now, such a large simulation was only conceivable in a gravity-only approximation."
The left image in the top graphic displays the evolution of the expanding universe over billions of years in a region containing a cluster of galaxies, while the right image illustrates the growth and movement of galaxies over time within that same image.
"It's not only the vast size of the physical domain that's required to conduct direct comparisons to contemporary survey observations enabled by exascale computing," commented Bronson Messer, the director of science for Oak Ridge Leadership Computing Facility, in a statement by the lab. "And the enhanced physical realism by incorporating baryons and all other dynamic physics that makes this simulation an impressive achievement for Frontier."
No longer the swiftest supercomputer in the world
Frontier is one of several exascale supercomputers utilized by the Department of Energy, boasting more than 9,400 CPUs and over 37,000 GPUs. Residing at Oak Ridge National Laboratory, these recent simulations were executed by Argonne researchers.
The Frontier findings were a result of the code supporting the supercomputer, the Hardware/Hybrid Accelerated Cosmology Code (or HACC). The fifteen-year-old code was restructured as part of the DOE's $1.8 billion, eight-year Exascale Computing Project, which concluded earlier this year.
Announced last month, when Frontier was still the fastest supercomputer worldwide, the simulation's results soon lost their title to the El Capitan supercomputer. El Capitan now holds the record for 1.742 quintillion calculations per second, with a total peak performance of 2.79 quintillion calculations per second, according to a statement by Lawrence Livermore National Laboratory.
Frontier's simulation of the universe's physics and evolution, including dark matter, paves the way for advancements in future technology and space explorations. With its ability to incorporate baryons and other dynamic physics, Frontier sets a new standard in astrophysical simulations, guiding the way science interprets dark matter's role in the universe's composition.
With the advent of more powerful supercomputers like El Capitan, the race to further unravel the mysteries of dark matter and the universe's composition continues in the realm of physics and technology, shaping our vision of the future.
