Uranus (Planet) — Facts, Moons, Atmosphere, and Exploration
Uranus is an ice giant with a pale blue color from methane in its atmosphere. It rotates on its side compared with most planets, producing unusual seasonal lighting patterns.
Quick Facts
| Planet type | Ice giant |
|---|---|
| Mean radius | 25,362 km |
| Mass | 86.8 × 10^24 kg |
| Gravity | 8.7 m/s² |
| Average temperature | -195°C |
| Length of day | 17.2 hours (retrograde) |
| Length of year | 84 Earth years |
| Number of moons | 27 |
| Rings | Yes |
| Distance from Sun (AU) | 19.2 |
What Makes Uranus Unique
Uranus has an axial tilt of roughly 98 degrees, meaning it effectively rolls around the Sun. This likely reflects an ancient giant impact or a series of collisions early in Solar System history.
Its interior and magnetic field geometry are also unusual, making Uranus important for understanding how ice giants form and evolve.
Atmosphere and Weather
The atmosphere is mostly hydrogen and helium, with methane that absorbs red wavelengths and gives the planet a blue-green tone. Although Uranus can look visually calm, telescopes have observed storms and cloud features, especially during seasonal transitions.
At great depth, pressure and temperature rise enough to form exotic fluid layers unlike Earth's atmosphere.
Moons and Rings
Uranus has 27 known moons and a narrow, dark ring system. Many moons are named after characters from Shakespeare and Alexander Pope, a naming theme unique among planets.
Exploration Highlights
Voyager 2 flew by Uranus in 1986 and remains the only spacecraft to visit. It provided crucial data on rings, moons, atmosphere, and magnetic field. New mission concepts aim to return and map Uranus in far greater detail, especially its interior structure and moon chemistry.
If You Like Uranus
Read Neptune for another ice giant, Saturn for dramatic ring science, and Jupiter for the largest gas giant.
Is Uranus an Inner or Outer Planet?
Uranus is an outer planet. It orbits far beyond the rocky inner planets and belongs to the group of larger worlds in the outer Solar System. For a quick comparison, see this difference between inner and outer planets guide.
Uranus Description
Uranus is a cold blue-green ice giant with a strange sideways rotation. It is larger than Earth, surrounded by rings and moons, and stands out because its tilted axis creates extreme seasonal changes.
FAQ
Why is Uranus tilted so much?
The most likely explanation is one or more large impacts early in its history.
Is Uranus colder than Neptune?
Yes, Uranus has very low atmospheric temperatures and emits less internal heat than Neptune.
Can we see Uranus without a telescope?
Under very dark skies and good conditions, Uranus can sometimes be seen with the naked eye as a dim point.
Is Uranus an inner or outer planet?
Uranus is an outer planet in the distant part of the Solar System.
What kind of planet is Uranus?
Uranus is an ice giant, a large outer planet with a deep atmosphere and icy materials in its interior.
Why is Uranus unusual?
Uranus is unusual because it rotates on its side, giving it one of the most extreme axial tilts of any planet.