Mr Kepler published a theory Prior to Copernicus, the generally accepted view was that the Earth was the centre of the Universe and the Sun, the stars and the planets were all in motion around it. However, like all astronomers before him Copernicus believed that the planets’ orbits must be perfect circles. Stephen Hawking worked on the physics of black holes. He proposed that black holes would emit subatomic particles until they eventually exploded. He also wrote best-selling books, the most famous of which was A Brief History of Time: From the Big Bang to Black Holes