Astronomy is probably the oldest of all the sciences. It differs from virtually all other science disciplines in that it is not possible to carry out experimental tests in the laboratory. Instead, astronomers can only observe what they see in the Universe and see whether observations fit the theories that have been put forward. Before we start our journey through the Universe in Chapter 2, I would like to share with you a little of the history of astronomy, looking at some of the astronomers who have, in the past, made great contributions to our knowledge.

Galileo Galilei’s proof of the Copernican theory of the Solar System

One of the first triumphs of observational astronomy was Galileo’s series of observations of Venus, which showed that the Sun, not the Earth, was the centre of the Solar System so proving that the Copernican rather than the Ptolemaic model was correct. He had made observations of Jupiter that showed four moons – now called the Galilean moons – weaving their way around it. This showed him that not all objects orbited the Earth.