Uranus, the seventh planet from the Sun, is a world of extreme seasons, mysterious weather, and a unique sideways rotation. Explore the secrets of this enigmatic ice giant.
Uranus is unique among the planets in our solar system because it rotates on its side. Its axis is tilted at an angle of about 98 degrees, which means it essentially orbits the Sun on its side.
This extreme tilt causes extreme seasons. Each pole gets around 42 years of continuous sunlight, followed by 42 years of darkness. The last equinox on Uranus occurred in 2007.
-224°C to -216°C
8.87 m/s² (0.886 g)
Uranus is an ice giant, composed primarily of water, ammonia, and methane ices, with a small rocky core and a gaseous atmosphere of hydrogen and helium.
The atmosphere contains methane which gives Uranus its blue-green color. Wind speeds can reach up to 900 km/h (560 mph).
Uranus has 13 known rings, all very faint and dark. The rings are composed of extremely dark particles that vary in size from micrometers to a fraction of a meter.
Largest moon of Uranus with a diameter of 1,578 km. It has a system of enormous canyons and scarps.
Second largest moon with a heavily cratered surface and possible subsurface ocean.
Darkest moon with a heavily cratered surface and mysterious bright-ringed crater.
Brightest moon with evidence of past geological activity and extensive valley systems.
The only spacecraft to visit Uranus, Voyager 2 flew by the planet in January 1986. It discovered 10 new moons, studied the planet's unique atmosphere, and examined its ring system.
The Hubble Space Telescope discovered two additional rings and two small moons (Mab and Cupid) in 2005. It also observed seasonal changes in Uranus's atmosphere.
NASA and ESA are considering missions to Uranus in the 2030s. The Uranus Orbiter and Probe would conduct in-depth studies of the planet's atmosphere, interior, moons, and rings.
Uranus is named after the Greek god of the sky. In Greek mythology, Uranus was the father of Cronus (Saturn) and grandfather of Zeus (Jupiter).
Uranus is just barely visible to the naked eye under very dark, clear conditions. It's often mistaken for a star due to its dimness.
Uranus was discovered by William Herschel on March 13, 1781, expanding the known boundaries of the solar system for the first time in modern history.
Despite being farther from the Sun, Neptune isn't the coldest planet - Uranus holds that record with temperatures reaching -224°C (-371°F).
Sign up for our newsletter to receive the latest discoveries and research about the mysterious ice giant.