... Star Wars in NGC 664 . ... Credit: C. Hergenrother, Whipple Observatory , P. Garnavich , P.Berlind, R.Kirshner ( CFA ) Explanation: Long ago in a galaxy far, far away, locked in their final desperate struggle against the force of gravity ... two stars exploded! stellar explosions - Supernovae - are among the most powerful events in the Universe, estimated to release an equivalent energy of up to 1 million trillion trillion (1 followed by 30 zeros) megatons of TNT. ... M3: Half A Million Stars . ...