Why Is Uranus Sideways?
The tilt was first measured in 1851, and for decades the most popular explanation has been a collision at a glancing angle with another planet, like the impact that gave birth to Earth’s Moon. One problem with this hypothesis is that none of the other planets have large tilts, despite experiencing the same kinds of collisions. Another is that Uranus' rings and moons are also tilted at the same angle, and a single collision could not have knocked everything on its side. A different explanation has been proposed recently that better fits our observations. Even Uranus’ largest moons are small in comparison the other giant planets, but if it had a large moon in the past and its orbit started drifting, gravitational tugging on Uranus and its other moons and rings could have gradually tilted all of them together. At some point, the moon’s orbit could have become chaotic, ultimately crashing into Uranus and locking the system’s tilt in place. Read More
Latest News About Uranus
New research challenges classification of Uranus and Neptune as ice giants
December 11, 2025
The composition of Uranus and Neptune might be less icy than previously thought, according to a new study. Read more
Uranus may have more in common with Earth than we thought
December 10, 2025
Scientists have worked out how a dense, shocked region of the solar wind could have manipulated Uranus' magnetosphere. Read more
Uranus's small moons are dark, red, and water-poor
December 8, 2025
…Except for Mab, which is even weirder than expected. Read more
Boiling oceans may sculpt the surfaces of small icy moons
November 25, 2025
Gravitational heating may thin ice shells enough to drop pressure and release vapor. Read more
Uranus and Neptune may not be 'ice giants' after all
October 13, 2025
We know very little about what's going on inside Uranus and Neptune, causing researchers to propose that these planets be called "rocky giants" instead. Read more
![Reprocessed images of Uranus [L]] and Neptune [R]](https://saganplanetwalk.com/wp-content/themes/saganplanetwalk2018/img/Uranus_100325_interiormodel.jpg "Reprocessed images of Uranus [L]] and Neptune [R]")
Icy or rocky? Convective or stable?
October 3, 2025
New interior models of Uranus and Neptune Read more
Scientists just solved Uranus’ coldest mystery
October 1, 2025
New computer modeling shows the planet actually emits more energy than it receives from the Sun Read more
A hidden ocean may have once existed on Uranus' moon Ariel
October 1, 2025
"Ultimately, we just need to go back to the Uranus system and see for ourselves." Read more
New moon discovered orbiting Uranus using JWST
August 19, 2025
The discovery expands the planet's known satellite family to 29 Read more
Uranus may actually be warmer than previously expected
July 18, 2025
Uranus releases about 15% more energy than it receives from the Sun according to new papers Read more
'Uranus is weird.' Big moons of tilted ice giant hide a magnetic mystery
June 11, 2025
"It's always been uncertain how much the magnetic field actually interacts with its satellites." Read more
Hubble helps determine Uranus' rotation rate with unprecedented precision
April 7, 2025
New measurements refine the accuracy of Uranus' interior rotation rate 1000 times greater than before Read more
20-Year Hubble study of Uranus yields new atmospheric insights
March 31, 2025
Findings offer new insight into how Uranus’s atmosphere responds to shifts in sunlight Read more
Uranus emits more heat than previously thought
March 11, 2025
All four of the sun’s giant planets emit more energy than they receive from the sun Read more
Deep chasms could lead to a hidden ocean on Uranus's moon Ariel
February 11, 2025
These grooves might be the best way of uncovering more details about the moon's interior Read more
Immiscible ice layers may explain why Uranus and Neptune lack magnetic poles
December 17, 2024
Their disorganized magnetic fields may arise from the icy fluids that make up their interiors Read more
Are there hidden oceans inside the moons of Uranus?
December 9, 2024
"Discovering liquid water oceans inside the moons of Uranus would transform our thinking about where life could exist." Read more
Uranus’s swaying moons will help spacecraft seek out hidden oceans
November 25, 2024
The largest of Uranus' 27 moons are able to keep the planet's stunted rings in check Read more
Neptune and Uranus have a magnetic mystery — but the case may finally be cracked
November 25, 2024
They have missing "dipole magnetic fields." Here's why that's really weird Read more
Long ago, Voyager 2 might have caught Uranus at a bad time
November 12, 2024
The spacecraft saw Uranus in conditions that only occur about 4% of the time Read more
New study on moons of Uranus raises chance of life
November 11, 2024
They may have oceans, and the moons may even be capable of supporting life, scientists say Read more
Uranus' moon Miranda may have an ocean beneath its surface
October 29, 2024
It may be one of the few select worlds in our solar system with potentially life-sustaining environments Read more
NASA images Uranus with epic team up of Hubble Telescope and New Horizons Pluto probe
October 11, 2024
The investigation shows what is needed to directly image more planets beyond the solar system. Read more
Some of Uranus' moons might be able to support life. Here's what a mission might reveal
October 1, 2024
Uranian moons could still host subsurface oceans at present Read more
Scientists finally know why ultraviolent superstorms flare up on Uranus and Neptune
September 16, 2024
Scientists have uncovered the secret ingredient fueling supercharged storms on Uranus and Neptune: methane. Read more
Investigating origins of CO2 ice on Uranian moons
August 29, 2024
A new study investigates the role of volatile migration in the unique Uranian thermal environment Read more
Fascinating Facts About Uranus
- If the sun were as tall as a typical front door, Earth would be the size of a nickel and Uranus would be about as big as a softball.
- From Uranus’ surface, the Sun appears about one-twentieth as large as it does from Earth and sunlight appears about 370 times dimmer.
- Uranus reaches the coldest temperature of any other planet even though it is not the farthest from the Sun.
- Many of Uranus’ moons are named after characters from the works of William Shakespeare and Alexander Pope.
- Uranus rotates on its side: it spins horizontally, and as a result of its sideways rotation, Uranus experiences around 20 years of night in the winter, 20 years of day in the summer and 42 years of night and day in the spring and fall.
- Uranus is an ice giant. Most (80 percent or more) of the planet's mass is made up of a hot dense fluid of "icy" materials – water (H2O), methane (CH4). and ammonia (NH3) – above a small rocky core.
Missions
Voyager 2 (1977)
Mission to study the outer solar system