We still don't know how magnetic fields started in the universe
From the silence of the Western Australian outback, a radio telescope array has translated the whispered language of four million galaxies into the largest map of cosmic magnetic fields ever assembled. Led by Australia's CSIRO, the effort answers a long-standing absence in our picture of the universe — the southern sky, unmapped for two decades, now rendered in unprecedented detail. At its heart, this achievement invites one of physics' oldest and most humbling questions: not merely how the universe looks, but what invisible forces have been quietly shaping it since the very beginning.
- For twenty years, scientists studying cosmic magnetism worked from the same incomplete dataset, blind to half the sky and unable to answer the most fundamental questions about where magnetic fields came from.
- Australia's ASKAP telescope array broke that stalemate by measuring how light from nearly four million galaxies twisted as it crossed intergalactic space — each bend a fingerprint of the invisible magnetic architecture between galaxies.
- The resulting map, SPICE_RACS, is five times larger and more detailed than any previous effort, finally charting the southern sky and giving researchers a coherent, global picture of cosmic magnetism for the first time.
- The full dataset has been released openly to scientists worldwide, transforming the map from a single discovery into a shared instrument — one that will drive new investigations into star formation, galaxy behavior, and the origins of the universe's magnetic skeleton for years to come.
Beneath the vast southern sky of the Western Australian outback, a radio telescope array has been listening to the universe. What scientists have now translated from its measurements is the largest map of cosmic magnetic fields ever created — one that may finally help answer where magnetism came from, and how it has shaped everything we see.
The map was built from light. Nearly four million galaxies sent their light across intergalactic space, and as it traveled, magnetic fields twisted it. A team led by Australia's CSIRO measured how that light bent and polarized, using those distortions to reconstruct the invisible magnetic architecture of the cosmos. The instrument responsible is the Australian Square Kilometre Array Pathfinder, ASKAP, stationed at the Inyarrimanha Ilgari Bundara observatory — powerful enough to scan enormous swaths of sky and peer deep into distant galaxies.
The stakes are high because the basic questions about magnetic fields remain unanswered. How did they originate? How have they evolved since the Big Bang? What role have they played in structuring the universe? Previous mapping efforts left vast blind spots, and for two decades researchers worked with essentially the same limited data — data that didn't even cover the southern sky. This new map, formally named SPICE_RACS, is five times larger and far more detailed than anything before it. Prof. Naomi McClure-Griffiths, chief scientist of the Square Kilometre Array observatory, called it a turning point.
Prof. Lisa Harvey-Smith of UNSW Sydney offered a reminder of why magnetism deserves the same attention we give gravity. Magnetic fields create light and color, protect Earth from solar radiation, and persist even in the emptiest regions of space. Stars and galaxies are magnets too — and understanding that invisible skeleton is inseparable from understanding how the universe works.
Critically, the full dataset has been released openly, making it available to scientists worldwide without restriction. The map is not an endpoint but a tool — one that researchers will use in the coming years to study star-forming regions, individual galaxies, and questions not yet fully formed. The discoveries that follow will likely reshape our understanding of how galaxies and stars are born, and how the universe's unseen magnetic forces have quietly governed everything we can observe.
Somewhere in the Western Australian outback, beneath the vast southern sky, a radio telescope array has been quietly listening to the universe whisper its secrets. What it heard—or rather, what scientists have now translated from its measurements—is the largest map of cosmic magnetic fields ever created, a chart so expansive and detailed that it may finally help answer one of physics' most fundamental riddles: where did magnetism come from, and how has it shaped everything we see?
The map exists because of light. Nearly four million galaxies sent their light traveling through the emptiness between stars, and as that light journeyed across intergalactic space, something twisted it. Magnetic fields. A team led by Australia's CSIRO, the country's national science agency, measured how that light bent and polarized, using those measurements to reconstruct the invisible architecture of magnetism that fills the cosmos. The instrument that made this possible is the Australian Square Kilometre Array Pathfinder, or ASKAP, stationed at the Inyarrimanha Ilgari Bundara observatory in Western Australia—a facility powerful enough to scan enormous swaths of sky and peer deep into distant galaxies.
Dr. Alec Thomson, an astronomer and astrophysicist at CSIRO, explained why this matters. Magnetic fields exist everywhere: in the Earth beneath our feet, in the stars above us, in entire galaxies, and in the seemingly empty space between them. Yet science has never adequately answered the most basic questions about them. How did magnetic fields originate in the first place? How have they evolved since the Big Bang? What role have they played in shaping the universe's structure? This map—formally named SPICE_RACS, short for Spectra and Polarisation In Cutouts of Extragalactic Sources from the Rapid ASKAP Continuum Survey—offers a new window into those mysteries.
The achievement is particularly significant because previous attempts to map cosmic magnetism had left vast blind spots. For two decades, scientists worked with essentially the same limited dataset, one that didn't even cover the southern sky. This new map is five times larger and far more detailed than anything that came before it, finally filling in territory that had remained unmapped. Prof. Naomi McClure-Griffiths, chief scientist of the Square Kilometre Array observatory and an author of the paper, called it a turning point: after twenty years of working with the same data, researchers can now tackle the big questions with a much clearer picture of how magnetic structures are distributed throughout the universe.
Prof. Lisa Harvey-Smith, an astrophysicist at UNSW Sydney who was not involved in the research, offered perspective on why magnetism matters as much as gravity in shaping the cosmos. Gravity is familiar—it pulls us to Earth, keeps planets in orbit, shapes the large-scale structure of the universe. But electromagnetism and magnetic fields are equally powerful forces. They create light and color. They're responsible for the compass needle that points north. On a planetary scale, Earth's molten core generates a magnetic field that protects us from solar radiation. Extend that principle outward, and you find that stars and galaxies are magnets too. Even in the emptiest regions of space, magnetic fields persist.
What makes this moment particularly valuable is that the data has been released openly. The Astronomical Society of Australia has published the full dataset, making it available to scientists around the world without restriction. Harvey-Smith emphasized that this is just the beginning. The map itself is not the endpoint; it's a tool. Over the coming years, researchers will use it to investigate specific star-forming regions, to study particular galaxies, to ask questions that haven't yet been asked. The discoveries that flow from this work will likely reshape our understanding of how galaxies form, how stars are born, and how the universe's invisible magnetic skeleton influences everything we can see.
Notable Quotes
We still don't actually know how magnetic fields started in the universe, or how they've changed across time since the big bang. And so this type of map helps us start to answer those questions.— Dr. Alec Thomson, CSIRO astronomer and astrophysicist
For the past 20 years we have been working with essentially the same dataset. Now, we can finally answer some big questions with a much better picture of the universe's magnetic structures.— Prof. Naomi McClure-Griffiths, chief scientist of the Square Kilometre Array observatory
The Hearth Conversation Another angle on the story
Why does it matter that we map magnetic fields in space? We can't see them anyway.
We can't see them directly, but we can measure their effects. Light gets twisted as it travels through them—that's what ASKAP detected. Understanding where magnetic fields come from and how they've changed since the Big Bang is as fundamental as understanding gravity. They're one of the two great forces shaping the universe.
But we've been studying magnetism for centuries. Why is this map different?
Scale and coverage. This dataset is five times larger than anything before it, and it's the first time anyone has properly mapped the southern sky. For twenty years, scientists were working with the same limited picture. This is like finally getting a clear view of half the universe we'd been squinting at.
Who uses this data now that it's public?
Any scientist anywhere. An astrophysicist in Chile might study how magnetic fields affect star formation in a particular galaxy. Someone in Japan might investigate how those fields have evolved over cosmic time. The map is a foundation—the real discoveries happen when thousands of researchers start asking their own questions.
What's the practical payoff? Does this help us on Earth?
Not directly, but understanding fundamental physics rarely has immediate applications. What we learn about magnetism in galaxies might eventually inform how we understand magnetic phenomena here. More importantly, it satisfies the basic human drive to understand how the universe works—and that curiosity has historically led to the most unexpected breakthroughs.
So this is just the beginning?
Exactly. The map is published, the data is open, and now the real work starts. Scientists will spend years finding things in this data that the creators didn't anticipate. That's how science progresses.