The Cassiopeia A supernova remnant glows in X-ray, visible, and infrared light in this Jan. 8, 2024, image that combines data from NASA’s Chandra X-ray Observatory and Hubble, Webb, and Spitzer space telescopes. A study by the XRISM (X-ray Imaging and Spectroscopy Mission) spacecraft has made the first-ever X-ray detections of chlorine and potassium from the wreckage; a paper about the result was published Dec. 4, 2025, in Nature Astronomy.
Read more about this discovery.
Image credit: X-ray: NASA/CXC/SAO; Optical: NASA/ESA/STScI; IR: NASA/ESA/CSA/STScI/Milisavljevic et al., NASA/JPL/CalTech; Image Processing: NASA/CXC/SAO/J. Schmidt and K. Arcand