Short-lived sudden explosions of gamma-ray photons, the most energetic form of light. Lasting anywhere from a few milliseconds to several minutes, gamma-ray bursts shine hundreds of times brighter than a typical supernova and about a million trillion times as bright as the Sun, making them briefly the brightest source of cosmic gamma-ray photons in the observable universe. They can be associated with supernovae, pulsars, convergence of neutron stars or Black Holes, and other energetic cosmic cataclysms.