The most accurate simulation of the universe ever. It contains 60 trillion particles

Scientists have created a giant simulation of the universe spanning billions of light years – the largest ever.

Astronomy still hides many mysteries. To unravel them, scientists use a two-pronged approach: observation and theoretical deliberation. Computer simulations that allow you to check the reliability of the generated theories are also a real help. The most recent one is AbacusSummit, created by Center for Computational Astrophysics (CCA) from the Flatiron Institute and Harvard-Smithsonian Center for Astrophysics (CfA).

The first such simulation in history

The abacus can handle nearly 60 trillion particles and is the largest cosmic simulation ever created. Details can be found at Monthly Notices of the Royal Astronomical Society.

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Countertop consists of more than 160 simulations that represent the behavior of particles due to gravitational attraction. These models are known as N-body simulations and are an integral part of modeling how dark matter interacts with baryon (or “ordinary”) matter.

Work on the countertop simulation was carried out by Lehman Garrison of CCA and Nina Maksimova and Daniel Eisenstein, alumni and professors of astronomy at CfA. Simulations were performed on the Summit supercomputer at Oak Ridge Driving Computing Facility (ORLCF) in Tennessee – under the supervision of the US Department of Energy (DoE).

The three-body problem

N-body simulation, which calculates the gravitational interactions of planets and other bodies, is one of the greatest challenges facing astrophysicists today. Every object interacts with every other, regardless of the distance between them – the more objects you study, the more interactions you need to take into account.

To this day, science does not know how to solve nth-body problems in which three or more massive objects are involved, and the available calculations are only approximations. The problem of the interaction of three bodies, such as the binary star system and the planet (commonly known as the three body problem), has not been solved.

How is the simulation performed? Scientists stop the clock, calculate all the forces acting on each object, turn the clock on, and repeat the whole thing N times. For their research, the team designed a database called Abacus to harness the power of Summit’s parallel processing, which allows multiple computations to be performed simultaneously.

This package is so large that it probably contains more particles than any other N-body simulations that have been run together – although it’s hard to be sure. Galactic studies provide incredibly detailed maps of the universe, and we need similarly ambitious simulations covering the wide range of possible universes we could live in. AbacusSummit is the first simulation suite to have enough scope and fidelity to match these amazing observations. Our vision was to create the code that would provide the simulations needed for this new type of galactic research. We’ve written code that makes simulation faster and more accurate than ever before.

Lyman Garrison