Before the IXPE telescope set its sights on the supernova remnant known as Cassiopeia A (Cas A for short), scientists were missing important information about the behaviour of magnetic fields. Many telescopes have studied this supernova remnant, but IXPE stands out for its ability to detect polarisation, a property of light rarely measured in space.

Polarisation allows us to understand how light waves move and reveals the shapes of things we would otherwise not be able to see. IXPE's observations of Cas A surprised scientists when it revealed results about the direction of the magnetic field lines that were not in agreement with previous observations. This new finding deepens our knowledge of the extreme conditions that occur when a massive star explodes.

Image description:

A composite image of the Cas A supernova remnant from the explosion of a star in the constellation Cassiopeia. Cas A appears as a spherical blue and turquoise cloud covered with golden streaks. The spherical cloud resembles a hazy ball of turquoise and neon blue lightning bolts with golden veins. The blue colours represent data from NASA Chandra Xray, the turquoise from NASA's Imaging X-ray Polarimetry Explorer (IXPE), and the gold from the Hubble Space Telescope.