Thomson et al. this week published the largest and most detailed map of cosmic magnetic fields ever made, using data from ASKAP. The second data release (DR2) of SPICE-RACS (Spectra and Polarisation in Cutouts of Extragalactic sources from the Rapid ASKAP Continuum Survey) covers the entire sky from the South celestial pole up to a declination of +49 degrees; approximately 87.5 % of the celestial sphere. The team produced ‘cutout’ spectral cubes in Stokes I, Q, U around 4 million radio sources and extracted spectra towards 5 million radio components.  This places SPICE-RACS DR2 as the largest single Rotation Measure (RM) catalogue ever produced by nearly an order of magnitude; the number of RMs in our catalogue alone is ∼5 times larger than every previous RM catalogue combined. The image above shows the SPICE-RACS RM grid overlaid on an optical image of the Milky Way from the ASKAP site. The map has red colours showing magnetic fields pointing towards us, and blue pointing away. Most of the RM structure visible in this image is from our Galaxy. (Image credit: CSIRO/Alec Thomson et al./Alex Cherney/Sam Moorfield)