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To purge yourself of the silly puns, go to Questions about Uranus.
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The Final Frontier
The abyss stares back

Uranus is the seventh planet (counted from the Sun) in the Solar System. It's a gas giant[note 1] like Jupiter, Saturn and Neptune. It is one of the two major planets discovered in modern times, as all of the rest are bright enough to have been known since ancient times.[note 2] (The other is Neptune. And Pluto is not a planet.)

Uranus is named after the Roman spelling/adaptation of Ouranos, the primordial Greek god/personification of the sky; as part of the interminable wars among the generations of Greek gods (before his grandson Zeus/Jupiter and his fellow Olympians put a stop to it, at any rate), he had his testicles cut off. By his own son (yes, Zeus' dad). Tough breaks. The name has been the target of an immature joke ever since it was discovered and named in the 1780s. According to some stuffy twerps, the planet's name is not pronounced the way the joke requires. It is actually pronounced more along the lines of "yoo-ruh-nuss" or "yur-uh-nuss," not "yer anus." Unfortunately that runs into urinous, and Webster's doesn't agree, both pronunciations are correct.[1] Can't win.[2] Some people take to pronouncing it, "yoo-ran-us" to avoid getting snickered at. Maybe you can win, after all! Why this whole issue wasn't avoided by naming the planet Caelus after the Roman god of the sky is a mystery for the ages. Maybe it's got something to do with the person discovering it being well read on ancient mythology but no native speaker of English, let alone a snickering fifteen year old schoolboy.

Uranus has an axial tilt of almost 90 degrees making its axis almost parallel to the plane of the ecliptic. It also has rings tilted nearly perpendicular with the ecliptic, 27 moons whose orbits at least for the largest and closest ones to the planet share such tilt too,[3] and a magnetic field that is not centered and is tilted at an angle to the axis of rotation. Fun fact: unlike the moons of all other planets (save Earth, of course), the moons of Uranus are not named after mythological figures, but rather after characters from the plays of William Shakespeare and from Alexander Pope'sWikipedia mock-epic poem The Rape of the Lock. This is because as the first planet to be discovered after the invention of a telescope, since it was discovered by someone living in England, it was deemed appropriate to name its moons after figures from prestigious works of British literature, in recognition of its discoverer's nationality. It was also felt that a sky god would logically be accompanied by air spirits, but later astronomers forgot that part and just randomly picked names from Shakespeare and Lock.


Uranus was actually discovered several decades before it was discovered. In 1690, John Flamsteed was cataloging all the faint naked-eye stars, and called Uranus "34 Tauri." It wasn't until 1781 that William HerschelWikipedia (born in Hannover and thus not a native English speaker) found how a supposed star also in the constellation of Taurus presented a well-defined disk instead of looking ill-defined and hazy as a comet would have looked. He initally wanted to name it after King George III -- the same guy America had declared independence from some years earlier -- but let's face it, "Planet George" is a stupid name (which is why it was never suggested) and Giorgium Sidus ("The Georgian Star", which is what Herschel actually proposed) is at least as stupid. It was Johann Elert Bode (not a native speaker of English either) who suggested Uranus, to preserve the mythological theme of the other planets. Bode's reasoning was that if Jupiter was the father of Mars, and Saturn was the father of Jupiter, then the next planet in line should be the father of Saturn. Unfortunately, he missed the mark a bit by Romanizing the Greek name rather than using the actual Roman name, and Uranus stuck.

Later observations of Uranus's motion indicated that an eighth unseen planet was tugging on it. This planet was eventually discovered, in precisely the position predicted by these calculations, and was named Neptune.

Moons and rings[edit]

Like the other outer planets, Uranus has its own system of moons and rings. Uranus is the only planet besides Saturn whose rings were discovered prior to being visited by the Voyager probes. When Uranus passed in front of a star, an event known as an occultation, Uranus's rings caused the star to "blink" right before and right after the planet itself passed in front of it, caused by the rings obscuring its view. Uranus's rings are much darker than Saturn's but otherwise similarly believed to be a recent development in astronomical terms. Being parallel to Uranus's equator, it has been noted that they make Uranus resemble a bullseye.

As mentioned above, Uranus has twenty-seven known moons in total. Five of these moons are massive enough to become round under their own gravity. These are Titania, Oberon, Ariel, Umbriel, and Miranda. They are collectively known to be very dark due to radiation darkening from interstellar radiation causing a substance called tholin to build up on their surfaces. Other than that, little is known about them because Uranus has not received any orbital probes.

Uranus is notable for being the only outer planet without a moon that rivals or surpasses Earth's in size, as the other three giant planets each have at least one. The reason for this is not known, but it has been noted that Uranus possess the only observed ice giant moon system that has not been disrupted, indicating that its comparatively small moons are normal and Neptune is the oddball of the two.

Of the five major moons (and it should be noted here that due to the aforementioned tilt of their orbits, Voyager 2, the only probe that has explored Uranus to date, was able to image just part of their surfaces as back in 1986, as the planet they orbit, one of their poles pointed to the Sun and the other was in darkness), the smallest and innermost, Miranda, is the only one that such spacecraft got a good look at and is currently the considered the most interesting. Its terrain is among the most extreme and varied in the solar system, and its Verona Rupes is the highest known cliff. Many hypotheses have been put forth to explain Miranda's terrain. One of the most well-known is that the entire moon was once shattered by an impact, then recoalesced later; this hypothesis is now considered unlikely. A more modern idea is that Miranda once possessed a subsurface ocean, which greatly disrupted its surface when it froze. Another is that Miranda is in fact still forming, as the process was somehow slowed down compared to every other object in the solar system.

Ariel and Umbriel are in the middle ground of the five major moons in both size and distance. Aside from the usual craters and radiation darkening, there is nothing to indicate that there is anything notable about them. Ariel, the second smallest moon after Miranda, is the most reflective of the five while the slightly larger Umbriel is the darkest.

Titania is the largest of the five, with the outermost moon, Oberon, a close second. Both are massive enough that subsurface oceans are a possibility, but without orbital probes there is no way to corroborate this.

Among Uranus's irregular moons, the two most notable are Cupid and Belinda. Examinations of their orbits indicate that at some point in the far future they will directly collide with each other. It is debated whether this will cause them to bounce off of each other into new orbits, merge into a much larger moon, or shatter each other and create a new and much brighter ring.

Fundamentalist Christian quote[edit]

Guess what happens when you find a planet? You get to name it! Well, Herschel was not ancient Roman who believed in false gods. In fact, he was a devout Christian. Because of this, he didn't want to name Uranus after a Roman god. Instead, he wanted to name Uranus after his king, King George III. Not everyone loved King George, however, so many people wanted Herschel to name Uranus after himself, calling it planet Herschel. In the end, they decided to keep with tradition and name Uranus after another Roman god. It is such a shame that the planets in God's wonderful creation, which were made for His glory, have been named after Satan’s counterfeit gods. One day, when we are in heaven, we will call the planets by God-honoring names.
—Exploring Creation with Astronomy[4][5]

The irony is that Ouranos came to mean "sky" or heaven in the Greek language, even outside of a mythological sense, and is even used in the Greek New Testament to refer to Heaven as God's abode.

External links[edit]


  1. Only its outer layers are gaseous. Most of the planet is an icy mantle made of solidified water, ammonia, and methane surrounding a solid rocky core-- it would be more appropriate to call Uranus an "ice giant."
  2. Uranus is just barely bright enough when observed from earth to be visible to the naked eye.