#PPOD: In November 1572, a brilliant new light appeared in the constellation Cassiopeia, catching the attention of Danish astronomer Tycho Brahe and other skywatchers. What seemed like a new star was actually the violent destruction of a white dwarf in a Type Ia supernova. More than 450 years later, NASA's Chandra X-ray Observatory reveals the expanding debris in extraordinary detail. Credit: X-ray: NASA/CXC/RIKEN & GSFC/T. Sato et al.; Optical: DSS
