THE DISCOVERY OF URANUS 

Before 1751, nobody knew of the existence of the planet Uranus. People believed that there were only six planets in the Solar System, including Earth. Mercury, Venus, Mars, Jupiter and Saturn are visible from Earth with the naked eye so had been observed by stargazers for thousands of years. The ancient Romans gave the planets their current names, believing that they represented their gods. However, the advent of the scientific age meant that what people knew about the universe around them was about to change.

The invention of the telescope was a huge leap in astronomy. Before it, astronomers had to rely on what they could see with their eyes. With a telescope, suddenly people could look further than the eye could see and for the first time observe worlds that nobody had seen before. Galilei Galileo made one of the first major discoveries using a telescope. In 1610, while looking at Jupiter, he noticed four points of light surrounding the planet. He soon realised that he had spotted four of Jupiter's moons, the first moons to be discovered elsewhere in the Solar System other than the moon orbiting Earth (which is pretty difficult not to see!). Scientists of the time began to get excited that there may be other mysterious worlds in the Solar System, and not just moons orbiting the six known planets. There may be new planets out there that they didn't yet know about waiting to be discovered!

The earliest known observation of a new planet was by John Flamsteed, an English astronomer, in 1690. He spotted an object which he thought to be a star and which he referred to as 34 Tauri. He made several other observations of this "star", again not realising he was looking at a planet. Other astronomers also observed the same object, but as its movement didn't differ from the other stars (the usual way of spotting a planet), they simply didn't recognise it as being a planet.

On 13th March 1751, while observing the night sky, the English astonomer and composer Frederick William Herschel (pictured left) noticed an object which didn't move across the sky like stars do. Initially believing it to be a comet, and naming it Georgium Sidus (George's Star) in honour of King George III, Herschel soon realised that his object may in fact be a planet. This suggestion was made by Nevil Maskelyne, the British Astonomer Royal. After doing a bit of mathematics, it was confirmed that Georgium Sidus was definitely a planet, and Herschel became a national hero, becoming the first person to "discover" a planet! As a reward for discovering this planet (and probably because he named it after the King) he became King's astronomer, meaning that his job was to look into the sky for the King!

The British were very proud of the discovery of the Solar System's seventh planet, and for almost sixty years, were happy to refer to it as George's Star. However, the rest of the world wasn't too happy, mainly because the name of the planet didn't fit in with the mythological names of the other planets, and partly for more political reasons. The Americans and French were especially reluctant to call the planet George's Star. Both countries were in a war against Great Britain and didn't want to refer to a planet named in honour of the King of its enemy. Instead, they knew it as Herschel. It was eventually the scientific community that succeeded in renaming the seventh planet. The name Uranus was chosen, named after the Greek god of the sky.