Planetary Facts about Uranus

Uranus is the seventh planet from the Sun in our solar system and is one of the 4 “Gas Giants”, along with Jupiter, Saturn, and Neptune.  Discovered by Sir William Herschel in 1781, the planet was named after the ancient Greek god of the sky. 


The mass of Uranus is approximately 14.5 times greater than that of Earth, making it the lightest of the gas planets in the solar system.  It’s equatorial radius measures at 25,559 km which is just over 4 times greater than Earth.  As far as size goes, Uranus is the third largest planet that orbits our Sun.  Due to its distance from the Sun and the path of its orbit, the revolution of Uranus takes an extremely long time.  One year on Uranus is the equivalent of 84 years on Earth.  One day on Uranus however, is much shorter than one here on Earth.  The planet rotates on its axis rather quickly making a day last 17 hours and 14 minutes.


Uranus is made up primarily of hydrogen and helium and temperatures in its upper atmosphere can reach -330 degrees Farenheit.  This causes clouds of ice crystals to form.  The methane in the planets atmosphere absorbs any red light, which is why Uranus appears blue in color.  While its made up mainly of gases, Uranus does have a rocky core that covers approximately 30% of the planet.

Ring System

Similar to Saturn, the planet Uranus has a system of at least 13 rings that revolve around it.  These rings are made up of tiny particles, and each ring is extremely narrow.  They measure no more than a few kilometres wide, making them extremely difficult to detect.

Moons and Satellites

There are at least 27 known satellites that orbit Uranus, and more may eventually be discovered.  The five main ones are Miranda, Ariel, Umbriel, Titania, and Oberon.  While Miranda is the smallest of these moons, it is arguably the most interesting.  Its varied terrain and wrinkled features suggest that parts of the moon were severely disturbed and possibly broke apart, then eventually fused back together.

Axis of Uranus

Unlike any of the planets in our solar system, Uranus has an axis of rotation that is tilted at approximately 98 degrees.  While all of the other planet’s rotations are similar to that of a top spinning, the rotation of Uranus is more like a ball rolling.  This causes extremely long seasons on the planet.  For example during the summer at the North Pole, the sun would be directly overhead for about 42 years.  Therefore during the winter time, the same Pole would be subject to complete darkness for 42 years. 


In 1986, the Voyager 2 was the first and only satellite to be sent anywhere near Uranus.  With no other plans to send out another satellite, any new information regarding the planet will have to come from the use of telescopes. 


Comins, Neil F: Discovering the Essential Universe.  New York, NY:  W.H. Freeman and Company, 2001.