Astronomers have just unveiled the universe's most detailed magnetic map—a breakthrough five times larger than every previous magnetic survey combined—opening a window onto one of the cosmos's most mysterious forces. The map, called SPICE-RACS, was produced by an international team led by researchers at CSIRO, Australia's national science agency, and the SKA Observatory, using data gathered by CSIRO's ASKAP radio telescope on Wajarri Yamaji Country in Western Australia.
For the past two decades, researchers studying cosmic magnetism have worked with essentially the same limited data set, one that didn't even cover the Southern Hemisphere. This new map changes everything. Lead researcher Alec Thomson, a commissioning scientist with the SKA Observatory, explains the significance: scientists can now investigate fine details of the material between nearby stars while simultaneously studying a vast number of distant galaxies. The scale and density of SPICE-RACS will help researchers finally understand how energy is distributed across the universe—a question that has lingered at the edge of astronomical knowledge.
The map's creation hinges on an elegant principle: light twists as it travels through magnetic fields. By measuring how twisted the light detected by ASKAP was across nearly 4 million galaxies, Thomson and his team could pinpoint where magnetic fields exist and gauge their relative strength. This massive data-processing feat only became possible through ASKAP's unique capabilities—its extraordinary field of view, distinctive dish rotation system, and the computational power to handle the enormous quantities of radio signal data involved.
Naomi McClure-Griffiths, the SKA Observatory's chief scientist and a leading expert in cosmic magnetism, sees SPICE-RACS as transformative. "For the past 20 years, we have been working with essentially the same data set, which didn't even cover the Southern Hemisphere," she explains. Now, researchers can finally answer fundamental questions. With detailed knowledge of magnetic fields throughout the universe, scientists can study how magnetism shapes galactic-scale interactions—such as how the Milky Way and the Magellanic Clouds influence each other. Even more tantalizing, researchers may finally answer questions once thought impossible: when did magnetic fields first appear in the universe?
Magnetic fields, it turns out, influence how galaxies grow, how matter moves through space, and how the universe has evolved over billions of years. Until now, this hidden architecture of the cosmos remained largely obscure. SPICE-RACS represents not just better data, but a fundamentally new capability to see cosmic structures previously invisible.
The telescope that made this possible—ASKAP, located at Inyarrimanha Ilgari Bundara (the CSIRO Murchison Radio-astronomy Observatory) in Western Australia—is itself a precursor to the international SKA telescopes now under construction in Australia and South Africa. ASKAP's success demonstrates what the next generation of radio astronomy will achieve.
What sets this discovery apart is its openness. CSIRO astronomer Tim Galvin emphasizes that the data is freely accessible to scientists worldwide through the data.csiro.au portal. "By having these resources freely available, we're supporting the continued advancement of our collective understanding of the universe," he says. Research teams are already using the data to produce new insights, accelerating the pace of discovery.
This is only the beginning. The international collaboration, called the Polarisation Sky Survey of the universe's Magnetism collaboration (POSSUM), is already publishing new scientific results. The universe's hidden magnetic architecture, once a mystery, is finally coming into view.