Additional Data:

Diameter:	50.724 km
Average distance to the sun:	2.872.400.000 km
The mass of 1 kg weighs on Uranus:	1.060 g
One year on Uranus lasts:	84 years 4 days
One day on Uranus lasts:	17 hours 14 minutes
Temperature on the surface:	-197 °C
Orbital velocity:	6,81 km/s
Orbital inclination:	0,7699 °
Orbital excentricity:	0,0472
Weight:	14,5 earth masses
Density:	1.271 kg/m³
Gravitational accelleration:	8,87 m/s²
Escape velocity:	21,3 km/s
Tilt oft the rotational axis:	97,7 °
Number of moons:	27
Number of rings:	13

 

In contrast to the five planets Mercury, Venus, Mars, Jupiter and Saturn, which have been known since ancient times, Uranus was only discovered in modern times. In addition to building reflecting telescopes, Wilhelm Herschel was also involved in astronomy and discovered the planet Uranus in 1781. He first named it "Georgium Sidus", i.e. "George's Star", in honour of King George III of England. Later, the Jesuit and astronomer Maximilian Hell proposed the name "Urania" after the muse of astronomy, and in France at the same time the planet was called "Herschel". The astronomer Johann Elert Bode finally proposed to name the new planet after the Greek god Ouranos, the deified sky. However, it was not until 1850 that this name became established in its Latin form "Uranus".

In 1790, the chemist Martin Heinrich Klapproth named a new element he had discovered the year before after the planet – uranium.

Uranus is the third largest planet in the solar system. It belongs to the ice giants because it does not have as large an atmosphere as Jupiter. It is twice as far from the Sun as Saturn. Inside, the planet is made up of several layers. The core is made of rock and is about the size of the Earth. This core is surrounded by frozen, partly liquid water interspersed with boulders. Uranus' atmosphere is made up of 83% hydrogen, 15% helium, and 2% methane, which gives it its blue color. Since the planet orbits very far from the Sun, it does not receive much solar radiation. This means that the weather is not as impressive as on other gas planets.

Uranus orbits the Sun once in just over 84 years. If you look at its axis of rotation, you will notice that it is very strongly inclined at 97°. This means that Uranus rotates retrograde, as if against the usual direction of rotation, clockwise, and appears to roll along its orbit. In the course of its year, it turns its poles towards the sun twice. The plane in which its moons and rings rotate is also tilted. It is unclear how this orientation came about. According to computer simulations, Uranus must have been hit by a protoplanet at least twice the size of Earth in order to tip that far.

After the Voyager 2 probe flew past Uranus in 1986, it was clear that Uranus has 27 moons and 13 rings. Unlike Saturn, Uranus' rings are made up of thin bands of ice and rock that date back to asteroids that have been torn apart by the planet's tidal forces. The first two moons, Titania and Oberon, were discovered by William Herschel as early as 1787. William Lassel discovered the moons Ariel and Umbriel in 1851 and Gerrit Kuiper found the moon Miranda in 1948. Ten more moons were discovered during Voyager 2's flyby, and between 1997 and 2003, observations with the Hubble Space Telescope added 12 more. While the name of Uranus was still based on Greek gods and mythical figures, the moons of Uranus were all named after figures from the works of William Shakespeare and Alexander Pope.

The 27 moons of Uranus are very different in their characteristics. Their diameters range from 1,500 km to just 160 km. The moons Miranda and Ariel are closest to Uranus. They both have a geologically young surface. Miranda is considered the most geologically active moon in the solar system. It consists of 80% ice and its surface appears to consist of a series of ice bergs drifting against each other. Ariel also has a high proportion of ice, but its surface is covered with fewer craters. The three moons Umbriel, Titania and Oberon are considered geologically old because they have many craters on their surface that were not filled after their formation. The other moons of Uranus are only between 10 and 100 km in size. About half of them orbit retrograde around the planet. They were probably trapped by the gravity of Uranus over time.