An innovative new computer model describing the expanse of charged particles and gas between stars reveals the Milky Way Galaxy’s magnetic turbulence, challenging the current understanding of astrophysical turbulence.
Known as interstellar mass, this cosmic medium filling the space between planets in the Milky Way has never been described in such detail. The team behind the achievement required the ultra-powerful SuperMUC-NG supercomputer housed at Germany’s Leibniz Supercomputing Centre to run their unprecedented model.
What Fills the Void
Even ultra-high vacuum experiments on Earth contain many more particles than the ocean of interstellar space. Yet, even those few cosmic particles manage to create a magnetic field similar to Earth’s core. With the sparseness of particles generating the field, its strength is millions of times below that of even refrigerator magnets, yet still enough to impact the universe around it, creating turbulence for objects traversing the cosmos. The behavior of that turbulence has been an unsettled problem for modern physics.
“This is the first time we can study these phenomena at this level of precision and at these different scales,” said lead author James Beattie.
“Turbulence remains one of the greatest unsolved problems in classical mechanics,” added Beattie. “This despite the fact that turbulence is ubiquitous: from swirling milk in our coffee to chaotic flows in the oceans, solar wind, interstellar medium, even the plasma between galaxies.”
A New Model of the Milky Way
The model was so computation-heavy that it required power equal to 140,000 computers operating at once to run.
“To put these massive simulations into perspective: if we had started one on a single laptop when humans first domesticated animals, it would just be finishing now,” said Beattie. “Luckily, utilizing the amazing resources from the Leibniz Supercomputing Centre, we can distribute the workload across thousands of computers to accelerate the calculations.”
The model is highly scalable, from a cube of 10,000 units per dimension, representing 30 light-years aside, to a version reduced by a factor of 5000. The largest scale provides insight into the Milky Way’s entire magnetic fields, while the smaller end provides the granularity needed for researchers to investigate how solar winds impact the Earth.
Milky Way Model Revelations
In the new model, magnetic fields affect energy traveling through interstellar mass by surpassing small-scale motions and increasing Alfvén waves, a type of wave-like disturbance. These findings conflict with decades of astrophysical theory, potentially altering how turbulence, high-energy particle transport, and star formation are understood.
“We are a step closer to uncovering the true nature of astrophysical and space turbulence, from chaotic plasma near Earth to the vast motions within our Galaxy and beyond,” said Beattie, “The dream is to discover universal features in turbulence across the Universe, and we’ll continue pushing the limits of the next-generation of simulations to test that idea.”
What Scientists Hope to Learn
With their new model, the researchers hope to illuminate many cosmic matters, such as the Milky Way’s magnetism, star formation, cosmic ray propagation, and interstellar mass.
“We know that magnetic pressure opposes star formation by pushing outward against gravity as it tries to collapse a star-forming nebula,” explained Beattie. “Now we can quantify in detail what to expect from magnetic turbulence on those kinds of scales.”
One of the team’s most significant achievements is its model’s ability to represent density changes across the interstellar mass, which can vary greatly and peak in star-forming nebulae. Crucially, a more dynamic understanding of interstellar mass will be of tremendous use to future space navigation, as crewed missions set their sights on Mars and beyond.
“The research has implications for predicting and monitoring space weather to better understand the plasma environment around satellites and future space missions, and also the acceleration of highly energetic particles, which damage everything, and could endanger human beings in space,” said co-author Amitava Bhattacharjee.
“A lot of these fundamental plasma turbulence questions are objects of missions now launched by NASA and have implications for understanding the origin of cosmic magnetic fields. Simulations like these would give us insights into how to interpret satellite and ground-based measurements,” added Bhattacharjee.
The Research Cycle Continues
Beatie’s team is not finished yet, though. They are continuing to push the model to an even higher resolution while testing their simulation against real-world data.
“We’ve already begun testing whether the model matches existing data from the solar wind and the Earth — and it’s looking very good,” says Beattie. “This is very exciting because it means we can learn about space weather with our simulation. Space weather is very important because we’re talking about the charged particles that bombard satellites and humans in space and have other terrestrial effects.”
Fortunately, new observation platforms provide plenty of data to check the model against and new details that require expanded frameworks to interpret. One prime example is the Square Kilometre Array in South Africa, which can precisely measure the galaxy’s turbulent magnetic fields.
“There’s something very romantic about how it appears at all these different levels and I think that’s very exciting,” Beattie concluded about the universal applicability of the team’s turbulence research.
The paper “The Spectrum of Magnetized Turbulence in the Interstellar Medium” appeared on May 13, 2025 in Nature Astronomy.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.