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Image: ESO

Uranus

Uranus appears to be quite oblique in the celestial landscape. It rotates horizontally around its own axis, and this points towards the Sun. It is therefore almost at a right angle to all the other planets. The most common explanation for this inclination is that it collided with a protoplanet (a planet that was not yet fully formed) during its formation. The inclined position leads to extreme seasons. While the Sun shines directly on one pole for 21 Earth years, it is dark winter on the other half during this time. As with Venus, Uranus' direction of rotation is also from east to west and, therefore, the other way around when compared to the other planets in our Solar System.
The ice giant has an atmosphere of hydrogen, helium and methane. The latter is responsible for the planet's blue appearance. It is surrounded by around thirteen rings, which in contrast to Saturn, are much less spectacular.

Uranus was discovered in 1781 by William Herschel with the help of a telescope and has only been visited once by a space probe. Voyager 2 flew past it in 1986 at a distance of 81,000 kilometres.

Uranus orbits the Sun at an inclination of almost 100 degrees
Uranus orbits the Sun at an inclination of almost 100 degreesImage: NASA/ESA and Erich Karkoschka, University of Arizona
  • Heliocentric distance: 19,201 AU
  • Mass: 8.6813 x 1025 kg,
  • Radius: 25'362 km
  • Orbital period: 84 Jahre
  • Rotation period: 17h 14min 24s
  • Solar constant: 3.71 W/m2
  • Number of moons: 27