For the first time, we can investigate fine details of material between nearby stars
For twenty years, those who study the invisible architecture of the cosmos worked with an incomplete picture — one that left out half the sky. Now, an international team led by CSIRO and the SKA Observatory has released SPICE-RACS, a magnetic field map of the Universe built from nearly four million galaxies and five times larger than all prior efforts combined. By tracing the way light bends through magnetic fields detected by the ASKAP radio telescope in Western Australia, researchers have opened a new chapter in humanity's long effort to understand the forces that shape how matter moves, how galaxies are born, and how the Universe itself has evolved.
- For two decades, a fundamental gap in cosmic knowledge persisted — no magnetic field data existed for the southern sky, leaving researchers to draw universal conclusions from a partial view.
- The release of SPICE-RACS shatters that constraint overnight, delivering a dataset five times larger than everything previously compiled, built from observations of nearly four million galaxies.
- The map works by measuring how light twists as it passes through magnetic fields, allowing scientists to infer both the location and strength of these invisible forces across vast stretches of space.
- The full dataset has been made publicly available through CSIRO's data portal, inviting researchers worldwide to pursue new questions or stress-test existing theories about cosmic magnetism and galaxy formation.
- The horizon is already shifting further — SKA telescopes now under construction in Australia and South Africa promise even finer mapping later this decade, potentially revealing how magnetic fields first came to exist in the Universe.
For twenty years, astronomers studying the Universe's magnetic fields worked from the same incomplete dataset — one that excluded the entire southern sky. That long constraint has now ended. An international team led by CSIRO and the SKA Observatory has released SPICE-RACS, a magnetic map of the cosmos built from nearly four million galaxies and five times larger than every previous effort combined.
The map rests on a straightforward physical principle: light bends as it travels through magnetic fields. By measuring the degree of that twist in signals captured by ASKAP — the Australian Square Kilometre Array Pathfinder, situated on Wajarri Yamaji Country in Western Australia — researchers could determine where magnetic fields exist across enormous stretches of space and how strong they are. The result is a dataset dense enough to study fine details near our own stars while simultaneously surveying vast numbers of distant galaxies.
Magnetic fields remain among the least understood forces in astrophysics, despite their suspected role in shaping how matter moves, how galaxies form, and how they evolve over billions of years. They resist direct observation, making maps like this one a rare and significant advance. Professor Naomi McClure-Griffiths, SKAO's Chief Scientist, noted that researchers can now finally address fundamental questions about cosmic magnetic structure with a genuinely complete picture.
The dataset has been released openly through CSIRO's data access portal, available to any researcher — whether pursuing new questions or verifying existing work. ASKAP itself is a precursor to the larger SKA telescopes now under construction in Australia and South Africa. When those instruments begin early operations later this decade, they are expected to enable even finer-grained mapping of the cosmic web and, perhaps for the first time, allow scientists to investigate how magnetic fields originated at all.
For two decades, astronomers studying the Universe's magnetic fields have been working with the same limited dataset, one that didn't even include the southern sky. That constraint has just ended. An international team led by researchers at CSIRO and the SKA Observatory has released SPICE-RACS, a magnetic map of the cosmos five times larger than every previous attempt combined, built from observations of nearly four million galaxies.
The map exists because of a simple physical principle: light bends as it travels through magnetic fields. By measuring the degree of twist in light detected by ASKAP, the Australian Square Kilometre Array Pathfinder radio telescope, the research team could infer where magnetic fields exist across vast stretches of space and how strong they are. Dr. Alec Thomson, a commissioning scientist with SKAO, described the implications plainly: for the first time, researchers can investigate fine details of material between nearby stars while simultaneously studying an enormous number of distant galaxies. The scale and density of the new dataset should help scientists understand how energy moves through the Universe and how that movement has shaped cosmic evolution over billions of years.
The work matters because magnetic fields remain poorly understood despite their suspected influence on nearly everything in space. They shape how matter moves, how galaxies form, how they evolve. Yet they resist direct observation. This new map, built by reprocessing original ASKAP data to extract rotation measures from every detected galaxy, represents a fundamental shift in what researchers can actually see and measure.
AKASP itself sits at Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory on Wajarri Yamaji Country in Western Australia. It functions as a precursor to the larger SKA telescopes now under construction in Australia and South Africa. The telescope's ability to survey large areas of sky at once made it ideal for the Rapid ASKAP Continuum Surveys, the underlying dataset from which SPICE-RACS was derived.
Professor Naomi McClure-Griffiths, SKAO's Chief Scientist and part of the research team, emphasized what the southern sky coverage means. After two decades working with incomplete data, researchers can now finally address fundamental questions about the Universe's magnetic structures with a much fuller picture. The dataset has been made available through CSIRO's data access portal, open to any researcher who wants to use it—whether to pursue entirely new questions or to verify existing work, an essential part of how science validates itself.
The release is part of the broader Polarisation Sky Survey of the Universe's Magnetism collaboration, which plans additional mapping campaigns using ASKAP in the coming years. But the real frontier lies ahead. When the SKA telescopes begin early operations later this decade, they will enable even finer-grained mapping of what astronomers call the cosmic web and should finally allow researchers to investigate how magnetic fields originated in the first place. For now, the Universe's hidden architecture is finally visible enough to study.
Citas Notables
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.— Professor Naomi McClure-Griffiths, SKAO Chief Scientist
La Conversación del Hearth Otra perspectiva de la historia
Why does mapping magnetic fields matter if we can't see them directly?
Because they shape everything—how galaxies form, how matter moves through space, how the Universe has evolved. We've suspected this for decades but couldn't measure it. Now we can.
How does measuring twisted light tell you where magnetic fields are?
Light doesn't travel in a straight line through a magnetic field. It rotates. By measuring how much it rotated by the time it reaches us, we can work backward and figure out where the field was and how strong it was.
Four million galaxies is a lot. Why was that number possible now when it wasn't before?
Better telescopes, better data processing, and finally—coverage of the southern sky. For twenty years we were working with incomplete data. This is the first time we can see the whole picture.
What changes when astronomers have this map?
They can ask questions they couldn't ask before. How is energy distributed across the Universe? What role do magnetic fields play in galaxy formation? These aren't new questions, but now there's actual data to answer them with.
Is this the final word on cosmic magnetism?
No. The SKA telescopes coming later this decade will be even more powerful. This map is the foundation. The real discoveries are still ahead.