As is often the case, it began with a series of observations that made no sense to anyone. A new generation of radio telescopes had come on stream on the 1950s that made it possible to see the universe in a completely different way. Almost immediately, they began to detect a series of strange, previously unseen sources of light. Nothing had ever been seen like them. 

 

These things looked very different, very strange, much more powerful, much larger, and really different than sorts of galaxies and stars in our neighbourhood.