Most Detailed Simulation of Magnetic Turbulence in Space Is Surprisingly Beautiful

A new simulation of the galaxy’s magnetic turbulence shakes up how we think about—and visualize—the astrophysical environments.

The model was developed by James Beattie, a postdoctoral fellow at the University of Toronto’s Canadian Institute for Theoretical Astrophysics and Princeton University, and collaborators from the U.S., Australia, and Europe. Described in a recent paper in Nature Astronomy, the model simulates space in high-definition—from volumes 30 light-years wide all the way down to tiny pockets scaled 5,000 times smaller.

“This is the first time we can study these phenomena at this level of precision and at these different scales,” Beattie said in a university release.

The simulation maps the chaotic dance of particles in the interstellar medium (ISM) with unprecedented precision. One aspect of the model is its ability to capture shifts in the interstellar medium’s density—from the near-emptiness of interstellar space to the dense clouds where stars are born.

The magnetic field that threads through our galaxy is millions of times weaker than a refrigerator magnet, but it nevertheless is a guiding force for matter in the interstellar medium. Galactic magnetism helps shape how stars form, how cosmic rays travel, and even how the solar wind messes with Earth’s magnetic field.

“We know that magnetic pressure opposes star formation by pushing outward against gravity as it tries to collapse a star-forming nebula,” Beattie said. “Now we can quantify in detail what to expect from magnetic turbulence on those kinds of scales.”

The simulation also scales down to help scientists probe phenomena much closer to home—namely the solar wind that streams from the Sun and bombards spacecraft and Earth’s atmosphere, generating brilliant auroras.

Early tests comparing the model’s results to real-world data of the solar wind look promising, Beattie noted, which indicates that the model could be used to predict space weather.

As more powerful radio telescopes such as the Square Kilometre Array come online to measure magnetic field fluctuations in the universe, among other things, the model can be fed data that improves its reflection of how magnetism shapes the matter all around us.

Deciphering the universe’s secrets is partly done through observation, but just as important are solid models of the forces that govern the cosmos. Magnetic fields have a hidden—but crucial—role in our Milky Way, and the new model helps us get closer to an accurate portrait of the galaxy.