Without the energy from the Sun, the Earth would have no life at all. Nowadays everyone knows that the Sun is a star. Like all stars, the Sun is a great burning ball of gases. To us, it seems large and red. The other stars look white or light blue because they are much farther from us than the Sun. In the past, many people believed that the Earth was the centre of the universe. They thought that the Sun and the stars went round it. Only in 1543, a great Polish scientist published a book in which he tried to prove a different point of view. According to him, the Earth and the other planets moved round the Sun. Those people who supported the scientist were often imprisoned and even killed.