Drawing of William Herschel – the blue ice giant Uranus is in the background

There are five planets you can see without a telescope or binoculars: Mercury, Venus, Mars, Jupiter and Saturn. People have known them for thousands of years.

Uranus [pronounced YOUR-uh-nuss] was the first new planet discovered.
William Herschel discovered it in 1781. Until then, people thought that Saturn was the most distant planet. Uranus was the first planet discovered with a telescope.

The new planet was almost named George.
Herschel called the planet after the king of England, George III, who supported him in his work. He chose the Latin name Georgium Sidus, which means George's Star. But astronomers outside England ignored this name. German astronomer Johann Bode suggested the name that finally stuck – Uranus was a sky god and father of Saturn.

Uranus is twice as far from the Sun as Saturn.
Herschel's discovery doubled the size of the known Solar System. Uranus is so far away it takes 84 years to go once around the Sun. Light from the Sun takes nearly three hours to get to it, so it's pretty cold out there. The planet's average temperature is -210° C (-350° F)

Uranus is an ice giant.
The gas giants, Jupiter and Saturn, are made mostly of the two lightest elements, hydrogen and helium. Uranus is smaller than they are and made up mostly ices of such as water, methane and ammonia.

Uranus is a blue-green color.
Like the other giant planets, the atmosphere of Uranus is nearly all hydrogen and helium. But in the extreme cold, there are methane crystals that soak up red light and reflect blue light, giving Uranus its color.

Sleepy Uranus
As a planet travels in its orbit around the Sun, it also rotates on its axis. The axes aren't all straight up and down. Some of the planets, such as Jupiter, stand up fairly straight, but others are more like Earth, tilted at an angle. Uranus is unique in that it seems to be lying down as it orbits.

Uranus has strange seasons.
A year on Uranus is 84 Earth years, so its seasons are 21 years long. In its summer, the northern hemisphere has 21 years of light, while the southern hemisphere lies in darkness for all those years. And when the planet is on the other side of the Sun, it's the northern hemisphere that doesn't get sunlight for 21 years.

Uranus and Venus rotate in the opposite direction to the other Solar System planets.
Astronomers think that in the early Solar System another massive body collided with Uranus, knocked it on its side and set it spinning in the opposite direction. (Venus probably also suffered some kind of collision.)

Uranus has 27 known moons.
There are five large moons, but almost all the rest are less than 160 km (60 miles) across. Solar System moons usually have names from mythology, but not the moons of Uranus. John Herschel named the first moons discovered using characters from English literature, mainly Shakespeare. Later discoverers stuck to the theme.

Surprise! Uranus has rings.
The rings of Uranus aren't beautiful like the rings of Saturn. Except for two colored rings, they are narrow and dark. William Herschel described a reddish ring in 1889, but no one else saw any rings until 1977. However, the Keck telescope in Hawaii has confirmed a ring like the one Herschel described.

William Herschel died in 1822, aged 84 – he had lived for one Uranian year.