For the first time, we can investigate fine details between nearby stars
For two decades, astronomers worked from an incomplete and lopsided portrait of the universe's invisible architecture. Now, an international team has released SPICE-RACS — a catalog of cosmic magnetic fields drawn from nearly four million galaxies — offering humanity its most expansive view yet of the forces that quietly govern how matter gathers, flows, and transforms across deep time. The map does not deliver final answers, but it replaces speculation with evidence, and in science, that is where understanding begins.
- For twenty years, researchers studying cosmic magnetism were constrained by the same fragmentary dataset, heavily skewed toward the northern sky and too coarse to reveal fine structure.
- The release of SPICE-RACS — five times larger than any previous magnetic field map — breaks that stalemate, cataloging light distortion across nearly four million galaxies to trace invisible forces at unprecedented scale.
- An international collaboration between Australia's CSIRO and the SKA Observatory drove the effort, with data now released publicly to invite the broader scientific community into the work of interpretation.
- The map opens direct lines of inquiry into long-deferred questions: how magnetic fields shaped galaxy formation, how they mediate interactions between the Milky Way and its neighbors, and when they first emerged in cosmic history.
For two decades, astronomers studying the universe's magnetic architecture were working from the same incomplete picture — fragmentary data that left the southern sky largely unmapped and made systematic study of distant galaxies nearly impossible. That constraint has now been broken.
The new catalog, called SPICE-RACS, was assembled by an international team at Australia's CSIRO and the SKA Observatory. Researchers trained radio telescopes on nearly four million galaxies, measuring how light bends as it passes through magnetic fields — a technique known as rotation measure — to chart the location and strength of these invisible structures. The result is a map five times larger than anything previously created, and detailed enough to examine the fine material between nearby stars.
Alec Thomson, the SKAO commissioning scientist who led the effort, notes that researchers can now conduct studies at a scale that was simply not possible before. The data has been released publicly through CSIRO's portal, opening it to the wider scientific community.
For SKAO chief scientist Naomi McClure-Griffiths, the moment marks a genuine turning point. The questions that have lingered for a generation — how magnetic fields shaped galaxy evolution, when they first appeared in the universe's history — can now be approached with real evidence. The map does not resolve those questions, but it builds the foundation on which answers can finally be pursued.
For two decades, astronomers have been squinting at the same incomplete picture of the universe's magnetic architecture. Now, with a map five times larger than anything previously assembled, they can finally see what they've been missing.
The new catalog, called SPICE-RACS, represents the work of an international team centered at Australia's Commonwealth Scientific and Industrial Research Organization and the SKA Observatory, an intergovernmental partnership building some of the world's most powerful radio telescopes. The researchers trained their instruments on nearly four million galaxies, measuring how light bends and twists as it passes through magnetic fields—a technique called rotation measure—to chart where these invisible forces live and how strong they are.
What emerges is a portrait of cosmic magnetism at unprecedented scale and detail. These fields are not decorative. They shape how galaxies assemble themselves, how matter flows through the void, and how the universe has transformed across billions of years. Yet until now, the data available to study them was fragmentary and skewed toward the northern sky, leaving the southern hemisphere largely unmapped. The new work fills that gap and goes far beyond it.
Alec Thomson, the commissioning scientist at SKAO who led the effort, describes the shift in capability plainly: for the first time, researchers can examine the fine structure of material between nearby stars and conduct systematic studies of distant galaxies in numbers that were previously impossible. The results have been released publicly through CSIRO's data portal, opening the archive to the broader scientific community.
Naomi McClure-Griffiths, SKAO's chief scientist, frames the moment as a turning point. For two decades, the field has been working with essentially the same dataset, constrained by its limitations. The questions that have lingered—how magnetic fields mediate interactions between the Milky Way and its neighbors, when such fields first appeared in cosmic history—can now be approached with real evidence rather than speculation. The map does not answer these questions outright, but it provides the foundation on which answers can be built. What comes next is the harder work of interpretation, of understanding not just where magnetism lives in the universe, but why.
Notable Quotes
For the first time, we can investigate fine details of the material between nearby stars, and study a huge number of distant galaxies.— Alec Thomson, commissioning scientist with SKAO
For the past 20 years, we have been working with essentially the same data set, which didn't even cover the southern sky. Now, we can finally answer some big questions with a much better picture of the universe's magnetic structures.— Naomi McClure-Griffiths, SKAO Chief Scientist
The Hearth Conversation Another angle on the story
Why does a map of magnetic fields matter to people who aren't astrophysicists?
Because magnetism is one of the fundamental forces shaping how galaxies—including ours—came to exist. If you want to understand why the universe looks the way it does, you have to understand the invisible forces that organized it.
But we've been studying cosmic magnetism for a while, haven't we?
Yes, but with one hand tied behind our backs. The previous maps were small and incomplete, mostly covering the northern sky. It's like trying to understand weather patterns by only looking at data from North America.
So this new map is just bigger?
It's five times bigger, but that's not the real shift. The density and coverage mean we can finally see patterns we couldn't see before—how magnetic fields connect galaxies, how they've evolved over cosmic time.
What does "rotation measure" actually tell you?
It's elegant, really. Light traveling through a magnetic field gets twisted. By measuring how much it's twisted, you can figure out where the field is and how strong it is. Four million galaxies, each one a data point.
What's the next step?
Now comes the interpretation. Scientists will use this map to answer questions that have been sitting unanswered for twenty years—when did magnetic fields first emerge, how do they shape the interactions between galaxies. The map is the foundation. The discovery is what comes next.