15 November: Sir William Herschel - Uranus

This date in 1738 was the birth date of Sir William Herschel, famous for discovering Uranus. 10 facts about the seventh planet:

1. Uranus is the only planet named after a Greek god rather than a Roman god, that is, the Greek god of the sky, Ouranos. He was the father of Cronus (the Greek equivalent of Saturn), and the grandfather of Zeus (the Greek equivalent of Jupiter).
2. It is also unique because it is the only planet in the solar system to rotate on its side, like a rolling ball rather than like a spinning top. This means its poles are where the other planets have their equators, and in the course of a Uranian year (84 earth years) each pole gets 42 years of continual sunlight followed by 42 years of darkness.
3. Uranus was the first planet to be discovered using a Telescope. Although it is visible to the naked eye (but only just) it was so dim that everyone thought it was a distant star until William Herschel noticed it while looking for double stars, and realised it must be a planet.
4. Originally, Herschel named the newly discovered planet the "Georgian Star" after the English King, George III. This didn't go down so well outside Britain, and so for a long time it was known as "Herschel", until the name Uranus was universally adopted in 1850.
5. The name had been suggested as a possibility 100 years earlier. The scientist Martin Klaproth was a supporter of calling the planet Uranus, and he was so sure it would catch on eventually that he named the element he had just discovered after it - uranium.
6. The planet is made up of frozen water, ammonia and methane, while its atmosphere consists of hydrogen and Helium. Although Neptune is further away, measurements have shown that Uranus is the coldest planet in the solar system.
7. Scientists believe that extreme temperatures and very high pressure compress carbon atoms into diamond, and that on Uranus, there are hailstorms where each stone is a diamond, and that there could be diamond icebergs floating in a sea of liquid diamond!
8. Uranus has rings - thirteen of them have been observed, most of them very narrow. Scientists think the rings are much younger than the planet and are the result of high speed impacts of moons. Talking of moons, Uranus has 27, named after characters in the works of Shakespeare and Alexander Pope. The five main satellites are Miranda, Ariel, Umbriel, Titania and Oberon. The moons are relatively small. The largest of them is only half the size of our moon.
9. William Herschel was a composer and musician as well as an astronomer. He played the oboe in the Hanover Military Band, as did his father and brother. He could also play the violin, harpsichord and organ, and composed 24 symphonies, some concertos and some church music.
10. The astrological symbol for Uranus includes a letter H, the first letter of Herschel's surname. In astrology, the planet is associated with Electricity, the colour electric blue, genius, individuality, unconventional and progressive ideas, discoveries, sudden and unexpected changes, freedom of expression and the nervous system. It rules the sign of Aquarius and the eleventh house.