The Sky at Night — Episode 7: Quasars

You are watching the episode Quasars What are the quasars, which may be close to the edge of the universe as seen from Earth? Are they made up of exploding stars, or are they the centres of galaxies in which great outbursts have taken place? Patrick Moore talks to Professor Alec Boksenberg about these strange, super-luminous objects which have set astronomers so many problems since they were first identified less than 20 years ago.