The Pulsar Powered Crab . ... Fading slowly, it remained visible for over a year. It is now understood that a spectacular supernova explosion - the detonation of a massive star whose remains are now visible as the Crab Nebula - was responsible for the apparition. ... Using a stunning series of visible light images taken with the Hubble Space Telescope (HST) , astronomers have discovered spectacular pulsar powered motions within the Crab nebula. ... NASA Official: Jay Norris. ...