Uranus is the seventh icy planet from the Sun in our solar system and is known for its unique characteristics. It is an ice giant of immense proportions with no solid surface, only swirling frozen hydrogen, helium, and methane gases. The methane gas gives Uranus a blueish appearance.
While we would understand your thinking that Uranus is a gas giant due to all the gases, it’s actually an Ice Giant! Uranus is an ice giant due to its very long distance from the Sun. It’s cold on Uranus! But more about that later.
At four times Earth’s diameter, Uranus is massive. So if Earth were apple-sized, Uranus would appear basketball-sized. And that’s a great analogy since the huge world rotates on its axis at about 98 degrees, making it look like a vast blue-green ball rolling through space.
The pronunciation of Uranus aside, the ice giant holds a world of mysteries, so let’s delve into some facts about Uranus. (Please don’t worry, but rest assured that we’ll let you know the proper pronunciation of the Ice Giant Uranus!)
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The best place to jump into cool things about Uranus is by looking at its discovery. In 1781, William Herschel discovered it through a telescope. At first, he thought it was a star or comet in the Gemini constellation. But later, he realized the object was a planet, meaning Uranus became the first planet found with a telescope.
Then, in 1783, astronomer Johann Elert Bode confirmed the existence of Uranus as a planet. And he suggested the name Uranus after the Greek sky god Ouranos as a continuation of Greek and Roman gods and goddesses’ nomenclature.
Thankfully, the scientific community accepted Bode’s suggestion. Otherwise, Herschel wanted to name the planet Georgium Sidus after Great Britain’s King George III. How’s that for a remarkable fact about Uranus?
However, scientists didn’t know much about the icy world for nearly two centuries because Uranus is so far from Earth. As a result, between 1787 and 1851, astronomers only found four moons orbiting the planet. And it wasn’t until 1948 that they found a fifth moon.
Later, they discovered the planet’s rings in 1977 when Australian scientists at the Perth and Kuiper Airborne Observatories observed Uranus pass in front of a star (SAO 158687.) This rare viewing opportunity revealed rings circling the ice giant.
However, it wasn’t until the 1986 Voyager 2 flyby that Uranus truly began revealing its mysteries.
What Are Some Interesting Facts About Uranus Exploration?
It took Voyager 2 nine years and more than 1.8 billion travel miles to visit Uranus. And then, it took only six hours for the spacecraft to gather critical information about the planet’s atmosphere, moons, and rings.
Voyager 2 flew about 50,600 miles (81,500 kilometers) above the planet’s clouds. Discoveries included two new rings and ten more moons.
The Hubble Space Telescope then made more discoveries in 2005, including a new ring pair and two more moons. The larger ring of the couple is twice the diameter of any previously known ones.
New Horizons also passed Uranus’ orbit while traveling to Pluto in March 2011, making it only the second spacecraft that far into the outer solar system since Voyager 2. But it didn’t gather information on the ice giant since it wasn’t near the spacecraft and the planet’s crossing point.
Location and Size
You’ll find Uranus in the far reaches of the outer solar system. It’s the seventh planet from the Sun, lying about 1.8 billion miles (2.9 billion kilometers) from our central star. At that vast distance, it takes sunlight about 2 hours and 40 minutes to shine on the frigid world.
In addition, Uranus is the third largest planet in the solar system, after gas giants Jupiter and Saturn. You can see it as the paler blue planet in the illustration below. Notice how it dwarfs Earth at about four times our home planet’s size.
About 63 Earth-sized planets could fit into Uranus’ expansive volume. And it has a gigantic radius of 15,759.2 miles (25,362 kilometers) with about 14.5 times Earth’s mass.
Uranus has a rapid spin that gives it a central bulge, similar to many other solar system planets. So that gives the planet a slightly narrower radius at its poles than at its center. In addition, if you could drive around Uranus’ equator (which you can’t since there’s no solid surface, plus you and your vehicle would instantly freeze and disintegrate), your trip would cover 99,018 miles (159,354 km).
Another interesting fact about Uranus is its crazy fast winds, second only to Neptune’s windy atmosphere. Winds on Uranus howl up to 560 miles per hour (900 kilometers per hour,) more than three times the strength of a Category 5 hurricane here on Earth.
Cat 5 winds reach upwards of 157 mph (252 km/h) and cause catastrophic damages. The National Hurricane Center says these winds would destroy many framed homes while also falling trees and power poles. Power outages might last for months, leaving an area uninhabitable.
So you can imagine the intensity of the winds on Uranus when they storm at three times Earth’s hurricane Category 5 strengths.
At the equator, winds blow retrograde, in the opposite direction of Uranus’ rotation. But winds shift to a prograde direction closer to the planet’s poles, where they flow with the natural east-to-west rotation.
Facts About Uranus: How It Gets Its Blue Color
Uranus gets its blue-green color from the methane in its atmosphere. Although it mainly contains helium and hydrogen, the relatively small amount of methane is enough to provide the planet’s serene blueness.
The Sun’s light pours through the atmosphere and then bounces off the lower clouds. When the light returns, the gasses absorb and filter out the red hues, leaving only blue greens.
In 1986, Voyager 2 saw a Great Dark Spot, a smaller dark spot, and only a few discrete clouds. So the planet mostly appeared as a swirling, solid blue color. However, newer observations show that the icy world has dynamic cloud formations. These clouds became especially apparent as the planet grew closer to its 2007 equinox. Observations showed bright features that rapidly changed, indicating a moving cloud system.
The Voyager 2 image below is perhaps one of the most iconic views of Uranus. It shows the ice giant in its blue-green splendor.
21 Years of Sunlight or Darkness
Another remarkable fact about Uranus is that it has decades-long seasons. The planet takes 84 long Earth years to orbit around the Sun, so that means each planetary season lasts 21 years.
December 2007 brought the northern spring equinox when the Sun stretched toward Uranus’ equator. During this time of the Uranian year, the planet has equal days and nights (8.5 hours each for a 17-hour day,) and the ice giant gets fully illuminated.
In 2028, Uranus will return to a northern hemisphere summer when the Sun shines directly over the North Pole. And that will send the southern hemisphere into its 21-year dark, cold winter.
But that doesn’t mean the northern hemisphere of Uranus is in for a warm summer! It’s an ice giant billions of miles away from the Sun, so temperatures remain hundreds of degrees below zero! There won’t be any sunbathing during a Uranian summer!
Can you imagine 21 years of constant sunshine or darkness with freezing cold temperatures during both summer and winter? That’s a seriously long time to wait to watch a sunrise!
It’s An Ice Giant With The Coldest Temperature In Our Solar System
Uranus is one of two ice giants, Neptune being the second. Even though the planet is filled with gas, it’s not a gas giant. And that’s because it’s so far from the Sun that it stays perpetually cold, making it an ice giant.
Most of Uranus’s mass comes from icy materials in a fluid form. Ammonia, methane, and water make up more than 80% of the planet over a small rocky core.
The core heats up to 9,000℉ (4,982℃) even though the planet’s average temperature is still minus 320℉ (-195℃.) The planet’s atmosphere is even colder than its mass, where temperatures dip to -371.5℉ (-224.2℃.) That makes it even more frigid than parts of Neptune. Now that is undoubtedly icy cold!
Uranus is so frozen that life, as we know it, can not exist. Scientists think the planet’s temperatures, materials, and pressures are too volatile for organic life. And if you could live there, you couldn’t build any sidewalks without a solid surface. So what’s the point?
One of the wildest facts about Uranus is its drastic tilt. The planet’s axis is almost parallel to its solar orbit, making it look like it’s lying sideways in space. With an inclination of 97.77 degrees, Uranus has an equator at a nearly right angle to its orbit. And if you’re wondering how that happened, it gets even wilder.
Scientists believe Uranus collided with a vast object, about one-three times the Earth’s mass, eons ago. The crash pushed the planet almost on its side, where it remains to this day. It’s hard to imagine a collision so violent that it caused Uranus to bolt sideways and then stay there.
In addition, the 27 moons of Uranus have the same tilt since they orbit the planet’s equator.
The Keck Observatory image below shows Uranus’ two hemispheres and its giant tilt. You can see the brilliant blues of the ice giant and even some of the brightness of its clouds.
The 27 Moons Of Uranus
Uranus has twenty-seven moons that are known to us now. And even though most moons of the other planets get their names from Greek and Roman mythology, Uranus is different. Of course, it is!
With twenty-seven moons, Uranus still has fewer moons than Juipter’s eighty-five moons but still contains nine times more than the four inner terrestrial planets. (Mars, Earth, Venus, and Mercury.)
The moons of Uranus get their names from the writings of Alexander Pope and William Shakespeare. See if you can guess which works of art each moon name stems from.
|Moon(s)||Discovered By||Discovered When|
|Oberon, Titania (the largest)||William Herschel||1787|
|Ariel, Umbriel||William Lassell||1851|
|Juliet, Puck, Cordelia, Ophelia, Bianca, Desdemona, Portia, Rosalind, Cressida, and Belinda.||Voyager 2||1986|
|Caliban, Sycorax||Palomar Observatory: B. Gladman, P. Nicholson, J. A. Burns, and J. Kavelaars||September 1997|
|Perdita||Voyager 2 Image, 1986/ University of Arizona’s Erich Karkoschka||Discovered from an image in 1999, Confirmed by Hubble in 2003|
|Prospero, Setebos, Stephano||Mauna Kea Observatory: Matthew J. Holman, John J. Kavelaars, Brett J. Gladman, Jean-Marc Petit, and Hans Scholl||July 1999|
|Ferdinand, Francisco, Trinculo||Cerro Tololo Inter-American Observatory: Dan Milisavljevic, Matthew J. Holman, John J. Kavelaars, and Tommy Grav||August 2001|
|Margaret||Mauna Kea Observatory: Scott S. Sheppard and David C. Jewitt||August 2003|
|Cupid, Mab,||Hubble Space Telescope: M.R. Showalter and J.J. Lissauer||August 2003|
Data: NASA Uranus Moons
- Tiny moon Perdita has a diameter of only about 18.6 miles (30 kilometers,) but that’s not the only thing interesting about it. A Voyager 2 image captured Perdita in 1986, but it wasn’t until thirteen years later that Erich Karkoschka, University of Arizona, found it when comparing images against Hubble pictures. A later 2003 Hubble image verified the tiny moon’s presence.
- The ancient moon Umbriel is the darkest of Uranus’ five largest moons. It sports giant craters that are almost as old as the satellite itself. It also has a bright ring on one side.
- Of the five major moons, Miranda is the smallest and innermost moon. It has an unusual surface full of enormous fault canyons. Some are up to twelve times deeper than the Grand Canyon, with terraced layers of varying ages.
- Scientists think the inner moons are half rock and half water ice. But the outer moons are probably captured asteroids whose compositions are unknown.
- A swarm of small satellites astounds astronomers who don’t yet understand why the moons don’t crash into each other. They think the moons could be shepherds for Uranus’ ten narrow rings, where even more moons may be hiding.
Lopsided Magnetosphere With A Corkscrew Tail
When a planet’s interior has convection in an area of electrically conducting fluid, it creates a global magnetic field. The amount of the fluid dictates the magnetic field’s strength. For example, less electrically conducting fluid equals a weaker planetary magnetic field.
Uranus’ interior lacks metallic hydrogen but has a weak magnetic field. Scientists think the field comes from hydrogen compound cores. Neptune’s composition and magnetic field are similar. But Uranus has a feeble magnetic field and an irregularly shaped magnetosphere compared to other solar system planets.
The magnetosphere forms when the magnetic field’s internal pressure interacts with the surrounding solar wind’s external pressure. And so, a planetary magnetosphere’s size depends on the solar winds’ and magnetic fields’ strengths. Jupiter has the solar system’s largest magnetospheres. And Uranus has one of the most unusual.
Where Does the Corkscrew Come From?
Uranus’ magnetic field is tipped over, tilted almost 60 degrees from its axis of rotation. It is also offset by a third of the planet’s radius from its center. As a result, auroras don’t align with the poles because of the tipped magnetic field. And that differs from auroras found on Saturn, Jupiter, and Earth.
But what about the corkscrew? No interesting facts about Uranus article is complete without including Uranus’ magnetosphere tail!
Because Uranus’ lateral rotation twists the lines of its magnetic field, the magnetosphere tail extends into space in a millions-of-miles-long corkscrew shape.
And that’s because Uranus doesn’t have a solid core. It has a small rocky core with layered non-convecting liquids. The thin outer core layer is convective, so it works with the planet’s spin and tipped magnetic field in a dynamo effect.
As a result, the magnetic field lines tangle with the planet’s liquid core creating chaos, rather than getting trapped and stabilized like happens on a planet with a solid core. So Uranus ends up with a tangled twist of a corkscrew magnetosphere tail.
Image: Pearson Education/Addison Wesley/Colorado.edu
Long Orbit Around The Sun
Because of its great distance from the Sun (~1.8 billion miles), Uranus takes a very long time to make its orbit. 84 Earth years, to be exact. And that’s about 30,687 Earth days.
So it’s reasonable to say that were it possible for a human to live on Uranus (which it isn’t), it is possible to spend one’s entire life in winter’s darkness or summer’s sun. Unless, of course, you happened to live during an equinox, and then you’d experience day and night in a 17-hour cycle.
But 84 Earth years as one Uranian year is a very long time. It might remind you of the space movie Interstellar when Matthew McConaughey’s character, Cooper, lost so many Earth years trying to rescue a researcher on a water world. The space-time continuum costs the astronauts dearly. And it would feel similar if a person were able to travel to Uranus (which you can’t.)
The 13 Rings Of Uranus
Scientists now know Uranus has two ring sets encircling the planet. Some of Uranus’ largest rings have fine dust belts surrounding them, but the rings have little dust overall. Most are only a few miles wide and opaque. Additionally, they are very dark, with the Bond albedo of the particles below 2%.
Most of the rings are likely water ice with dark radiation-processed organics. And scientists think they are less than 600 million years old, likely originating from moon collisions. As the satellites broke up, their surviving particles became dense rings.
The inner system has nine rings which are primarily dark grey and narrow. The outer ring pair consists of two types of rings.
- The innermost of the ring pair looks similar to the dusty reddish rings found around other solar system rings.
- The outer ring in the pair is blue, like the E ring around Saturn.
The rings are named as follows, starting with the closest rings to the planets and increasing in the distance away.
While the mechanism confining the rings isn’t wholly understood, Voyager 2 did discover on shepherd pair of moons (Ophelia and Cordelia) that corral the brightest ring into shape. And astronomers believe Rosalind and Portia shepherd another ring.
The illustration below depicts Uranus’ complicated moon and ring system, where dashed lines show the moons’ orbits and the solid lines show the planet’s rings.
Uranus and Astrology
In astrology, Uranus’ tilted spin aligns with its symbolism. The ice giant represents rebellion, upheaval, and eccentric behavior. It is full of raw genius, and because it is distant with frigid temperatures, mundane matters mean nothing to Uranus. Instead, it embraces the long-term with radical change at its heart.
Uranus rejects conformity and isn’t afraid of choosing chaos instead of structure. Uranus rules the astrological sign of Taurus, which is associated with the physical world, materiality, resources, and the physical world. And that’s why when it comes to the heart of a matter, Uranus prioritizes humanity’s greater good.
So Uranus has a chaotic nature, but it is tempered by the Bull’s traditional, pragmatic nature. It earned the nickname, the Great Awakener, with its strong impulse for shock and independence. And the ice giant stays in an astrological sign for seven years, taking 84 years to circle the zodiac (and the Sun.)
Uranium Gets Its Name From The Ice Giant
In 1789, a German chemist, Martin Kaproth, discovered uranium just eight years after the planet’s own discovery. The radioactive element came from the Joachimsthal silver mines in Czechia, where the chemist was analyzing pitchblende samples.
Kaproth named the element Uran after the still newly-found planet, Uranus. And today, we call it uranium.
We know you’ve been waiting on pins and needles to find out our absolutely correct astronomy answer concerning how to pronounce Uranus. Most Americans pronounce Uranus as “your anus.” A planet that smells like hydrogen sulfide and rains diamonds can handle a few sophomoric jokes, so go ahead and laugh it up a bit!
In 1986 NASA was preparing for the Voyager 2 spacecraft to fly past Uranus. Knowing that reporters, engineers, scientists, and the general public would struggle with a serious discussion about Uranus and deep space probes, NASA began to emphasize the pronunciation as “URINE-US.”
Today, you’ll find astronomers pronouncing Uranus in many different manners, but we know what they mean. When all else fails, just call it the “seventh planet from the sun.”
Conclusion: Why Is Learning Facts About Uranus Important?
Uranus is essential to our solar system because each planet helps the system hold its stability. The Sun and its planets create gravitational interactions that keep each world in its “correct” orbital motion. If a collision or disturbance significantly alters the distances between planets and the Sun, it could lead to more significant orbital instabilities and crashes.
Additionally, learning facts about Uranus is not only entertaining, but it also teaches us about the vastness of space and the worlds inhabiting it. Learning fun facts might make you more fabulous at dinner parties, too. But the main reason to know about our planets is that it helps us understand how the solar system formed and possibly even where it may head in the future.
So here’s a shortened list of some of Uranus’ most amazing statistics.
- Uranus is four times the Earth’s diameter and 14.5 times its mass.
- Uranus is the first planet found with a telescope: 1781 by William Herschel.
- The planet’s elliptical orbit makes the average distance from the Sun to Uranus 1,783,744,300 miles (2,870,658,186 kilometers.) That’s about 19.2 astronomical units.
- Voyager 2 is the only spacecraft to travel near and capture data about Uranus, 1986.
- Uranus is one of the solar system’s two ice giants in its far outer reaches.
- A Uranian day is 17 hours and 14 minutes, while a Uranian year is 84 Earth years. So it takes the planet about 30,687 Earth days to make one trip around the Sun.
- Uranus has 13 rings and 27 moons.
- Uranus rolls through the skies on a tilted axis, about 98 degrees.
- Uranus gets its blue-green color from the small amount of methane in its atmosphere.
- Uranus has the coldest temperatures in the solar system, with the atmosphere dipping to negative 371.5℉ (-224.2℃.)
- Uranus has a corkscrew-shaped magnetosphere tail drifting millions of miles into space behind it.
- Seasons on Uranus last 21 years, with perpetually dark winters and sunlit summers. But it’s still brutally cold, even when the sunshine finally reaches the planet.
- The founder of the element uranium got inspired by the newly-found planet when selecting a name for his discovery.