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Uranus (planet)


In astronomy, Uranus is the 7th planet from the sun in the solar system. It was one of the first planets to be discovered specifically by telescope observations. William Herschel is credited with it's discovery as an actual planet of the solar system, though a number of other astronomers noticed the object quite a number of times before but didn't realise it was a planet. This is because it orbits very slowly and appears very dim and fuzzy.


Uranus appears almost entirely featureless, even close up from the spacecraft Voyager 2 in 1986, so far the only craft to visit it. image: NASA/JPL

Orbit basics:

  • Distance from sun: between 2,748,938,461 and 3,004,419,704 km
  • Orbital period (it's year):  84.016846 yr
  • Moons(Natural Satellites): 27
  • The largest are Oberon and Titania (named after characters in Shakespeare's Midsummer night's dream)
  • Faint rings
  • The Uranian axis of rotation is approximately parallel with the plane of the Solar System, with an axial tilt of 97.77° (as defined by prograde rotation). This gives it seasonal changes completely unlike those of the other planets. Near the solstice, one pole faces the Sun continuously and the other faces away.


Dark spot observed on Uranus with the Hubble Space Telescope. image: NASA/ESA 2006 wikipedia

Planet basics:

  • Type of planet: Gaseous giant (ice giant)
  • Length of day: 17.24±0.01 hr
  • Average radius (equator): 25, 559±4 km
  • Mass: 86.8103 x 1024 kg
  • Gravity near cloud tops: 8.87 m/s2
  • Temperature of cloud tops: 76±2 K (-197°C)
  • Atmosphere: Thickness varies with depth to core, extreme wind speeds and planetary scale cyclonic storms.
  • Pressure: varies according to depth to core.
  • Atmospheric composition: 
  • Hydrogen, Helium, 
  • Methane (2%)


wikipedia link