What makes a scientific discovery really important? It's partly down to how much scientists use the discovery in subsequent work -- but it’s also partly down to what inspires their imagination. In this episode, the Hubblecast talks to some leading astronomers about their favourite Hubble discovery. Meanwhile, our presenter, Dr J, struggles to make up his mind.What makes a scientific discovery really important? It's partly down to how much scientists use the discovery in subsequent work -- but it’s also partly down to what inspires their imagination. In this episode, the Hubblecast talks to some leading astronomers about their favourite Hubble discovery. Meanwhile, our presenter, Dr J, struggles to make up his mind.