This animation shows a three-dimensional visualization of a core-collapse supernova simulation using the Chimera code on Titan, the Cray XK7 supercomputer at Oak Ridge National Laboratory’s Leadership Computing Facility. The colors show entropy, the degree of disorder in the stellar material circulating and recirculating behind the bounce shock emanating from the star’s core over the span of about 180–200 milliseconds. The first sequence shows the star in cross-section to show the circulation, along with a surface to mark the shock position. The second is a volume rendering of the entropy with low, medium, and high entropy highlighted to show the interplay of the standing accretion shock instability (SASI) and neutrino heating. Credit: Mike Matheson and Bronson Messer, Oak Ridge National Laboratory.