A new exhibition marking the 400th anniversary of Galileo’s work is set to open in the Vatican. The Catholic Church once labelled Galileo, now regarded as modern astronomy’s founding father, a heretic. He was tried for challenging the widely held belief that the sun travelled around the Earth. Although Copernicus did much ground-breaking work on the link between the sun and the Earth, it was Galileo’s instruments that proved the theory. It was not until 1992 that Pope John Paul II declared that the Church’s ruling was an error and that Catholics were not hostile to science.