Shakespeare's Moons, the moons of Uranus - Bob the Alien's Tour of the Solar System Welcome to Uranus The Tilted Planet Discovery of Uranus Shakespeare's Moons Miranda, a moon of Uranus Facts about Uranus Thousands of years ago, when the Romans and Greeks were naming the planets that were visible to them, they decided to name them after their gods. Mercury (Greek: Hermes) was the Roman god of commerce, travel and industry, Venus (Greek: Aphrodite) was the goddess of love and beauty, Mars (Greek: Ares) was the god of war, Jupiter (Greek: Zeus) was the king of the gods, and Saturn (Greek: Cronos) was the god of agriculture. Hundreds of years later, even when people knew that the planets weren't actually gods, they still kept with tradition and named newly discovered planets after mythological characters. Uranus, Neptune and Pluto were all discovered in modern times, but their names are all still linked to ancient myths. Uranus is the Greek ruler of the heavens, Neptune (Greek: Poseidon) is the Roman god of the sea, and Pluto (Greek: Hades) is god of the underworld.

The names of moons orbiting planets are also influenced by mythology. This is all except for one planet. The moons orbiting Uranus are named after characters in plays, mostly after characters in plays written by William Shakespeare. Why would you name moons after characters in a play though? Before I answer that, here's my quick guide to Shakespeare. One of the greatest ever writers of the English language was William Shakespeare. He was born on 23rd April 1564 in Stratford-upon-Avon, England and during his life, wrote about 154 poems (called sonnets) and 38 plays. From 1588, he lived in London where many of his plays were performed in front of the courts of the Royal Family. Although his plays are now over 400 years old, they are still performed and studied today, containing themes and ideas which are as relevant now as they were when they were first written. The Globe Theatre in London was opened in 2000 and is a modern day replica of the type of theatre in which Shakespeare's plays would have originally been performed. Some of Shakespeare's most famous plays are Romeo and Juliet, Macbeth, Hamlet and A Midsummer Night's Dream.

Shakespeare died on 23rd April 1616 and is buried in Stratford-upon-Avon church. Although Shakespeare wrote a large number of plays, these plays can be placed into four categories: Comedies, Histories, Tragedies and Romances. The Comedies were often farcical comedies of error, kind of like Fawlty Towers for the 16th Century (e.g. A Midsummer Night's Dream) . The Histories were based on real historical events, usually about English history (Henry IV, Part 1) or ancient history. Tragedies were plays with darker themes (such as betrayal and jealousy) and by the end of the play, most of the characters had died! (Romeo and Juliet, King Lear). The Romances were a bit lighter in theme and featured elements of fantasy and magic (A Winter's Tale, The Tempest). William Shakespeare is a hugely influential figure in English literature today. Students still analyse and discuss his works, and tourists from all over the world visit Stratford-upon-Avon to visit Shakespeare's house (pictured right).

His importance inspired William Herschel in 1787 to name some of the moons known to be orbiting Uranus after characters in Shakespeare's plays. In 1781, Uranus became the first planet to be " discovered ". The other planets that were known of at the time ( Mercury , Venus , Mars , Jupiter and Saturn ) plus the Sun and the Moon had been observed for tens of thousands of years from Earth and already had names, named by the Greeks and Romans after their gods. Before 1781, nobody knew that Uranus existed and people thought there were only six planets in the Solar System. Although Uranus had already been spotted numerous times, it was English astronomer William Herschel who first recognised that Uranus was actually a planet and not a star . Because the planet was discovered by an English astronomer , not an ancient Roman or Greek, it was very nearly named Georgian Sidus ("George's Star"), in honour of England's ruler at the time, King George the Third. Unsurprisingly, the scientific community didn't really like this name, wanting the new planet to keep the tradition of being named after Roman or Greek gods.

So the seventh planet in the Solar System became known as Uranus, a name suggested by German astronomer Johann Elert Bode. In 1787, a few years after discovering Uranus, William Herschel discovered two large moons orbiting the planet. Wanting to honour his British background once more, Herschel decided this time to honour the greatest playwright in English history by naming the two moons after characters in one of his plays. The moons were named Titania and Oberon after the King and Queen of the Fairies in Shakespeare's A Midsummer Night's Dream. Again, some people (such as the German ambassador) kicked up a fuss, wanting the moons to be named after classical figures, but the names chosen by Herschel remained and the tradition of naming moons of Uranus after literary characters began. In 1851, William Lassell discovered two more large moons orbiting Uranus. These were named Ariel and Umbriel. Ariel and Umbriel are characters in Alexander Pope's The Rape of the Lock, names chosen by Willian Herschel's son, John.

These are the only two moons orbiting Uranus named after characters in non-Shakespearean plays, although one of the main characters in The Tempest by Shakespeare is also named Ariel. The next moon to be discovered was in 1948 by American astronomer Gerard Kuiper. This moon was named Miranda, another character from The Tempest. It wasn't until Voyager visited Uranus in 1986 that any more moons were discovered. All of these moons, and all moons discovered since then have been named after characters in Shakespeare's plays. Even moons yet to be discovered will be named after Shakespeare's characters. He may have knew his plays were pretty good back when he was writing them, but even Shakespeare wouldn't have imagined that his characters would one day become immortalised in worlds millions and millions of miles away from his home in Stratford! Here is a list of all of the moons of Uranus, their size and location, the date they were discovered and where their names originate. Name A Moon By Any Other Name A Moon By Any Other Name By Laurance R.

Doyle, SET Institute | February 17, 2005 06:27am ET MORE Did you ever wonder how newly discovered moons and new features on planets are named? When Galileo first aimed a telescope at the Moon in 1610 he saw mountains that looked very much like Earthly mountains. Thus we have a the lunar Alps, Caucasus, and Appennes Mountains named after terrestrial mountain ranges. The vast dark lava-flooded areas he saw he mistook for vast seas (mare in Latin) and thus we have the Sea of Tranquility, where the first Apollo 11 astronauts walked on the Moon, the Sea of Serenity, the Bay of Rainbows (Sinus Iridium) and the huge impact remnant known as Ocean Procellarum - the Ocean of Storms. Craters, however, and some other smaller features are named, on our Moon, after philosophers and scientists. For example, a most obvious crater on the side of the Moon that always faces us (the moon is tidally locked to rotate at its orbital rate) is the huge rayed crater Copernicus.

It is so large that if you were standing on it you would not know that you were in a crater (the horizon on the moon is only two miles away and Copernicus is almost 300 miles in diameter). There is the crater named Tycho near the south lunar pole. It's rays lead to the impact crater Kepler - since Kepler, the first modern astronomer and the first to discover how the planets moved, used Tycho Brahe's observations to derive his three planetary laws of motion (so the rays sort of indicate Tycho sharing his data with Kepler). Aristarchus is another small but obvious crater; the interior is made of the brightest material on the moon. Like Aristarchus himself (who lived in the 3rd Century B.C. and was the first to point out that the Sun was the center of the solar system) the crater, while having little impact on the surrounding Moon, shines more brightly than any other spot on the Moon. Socrates, Plato, Archimedes, Tsilkovsky, Pasteur, Kuiper are all crater names on the Moon along with other great ancient and modern philosophers and scientists.

On the back side of the Moon, because Russia was the first to observe it (the first spacecraft to orbit the Moon) the largest maria (singular of mare) is the Sea of Moscow. But what about feature on, for example, the planet Mercury? These are generally named after famous authors and composers. (By the way, the naming of the celestial bodies is the task of the naming committee of the International Astronomical Union; star names have been recently sold arbitrarily along with a picture of the star, but this questionable practice has never been recognized by the IAU and such names are never used by the professional astronomical community). Thus we have craters on Mercury named Tolstoy, we have Bach crater, and the Wagner Mountain range there. On Venus, with one exception (the Maxwell mountains named after the great 19th century physicist James Clerk Maxwell) all features are named for famous women. There we can find Sacagawea crater, Florence Nightingale rile, Cleopatra caldera, and the Frejya (the Norse lady whom the day of the week, Friday is also named after) Mountains.

As other examples, on Mars valley networks are generally named after rivers or other languages' names for Mars or planets--many ancient languages are used. For example there is Auqakuh Valley (Incan for "Mars"), Dzigai Valley (the name for "river" in Navajo), Nirgal Valley ("Mars" in Babylonian), and the Reull Valley (the word for "planet" in Gaelic). Since Jupiter has no surface,(none of the gas giant planets do) there are no lasting impact craters to be found there, but the innermost large moon of Jupiter, named Io, is known to be the most volcanically active moon in the solar system with up to a dozen simultaneous volcanoes being seen spouting material hundreds of kilometers into space when a spacecraft last looked. Such features on this moon are thus named after fire gods, such as Pele (the Hawaiian goddess of fire whose work is clearly evident on the big island of Hawaii which grows by about 30 acres each year), Loki (the trickster blacksmith of the Norse), Masubi (the Japanese god of fire), and Surt (the Icelandic volcano god).

Large ringed features on the Jovian moon Callisto, for example, are often named after "heavens" such as Valhalla (the heaven of the Vikings), the largest impact crater in the solar system or Adlinda, the place deep in the ocean where souls go in the Inuit mythology. Skipping around, we find that the largest rings of Saturn are named A, B, and C for asymmetric, bright, and crepe rings (clearly planetary scientists were not expecting the thousands of rings found there by the Voyager spacecraft). However, the dubious pleasure of having gaps (clearings in the rings) named after one goes to Cassini (the Cassini division is a gap in between the A and B ring), Maxwell (he also figured out the nature of the rings), and Keeler--the first director of Lick observatory in San Jose, California, who observationally proved that the inner rings indeed rotated faster than the outer rings (i.e., the rings were really particles in orbit around Saturn). As other examples, many features on Saturn's moon Mimas are named after characters in King Arthur's court. We have Galahad, Lancelot , Kay, and Guenevere craters there.

The features on the moon Enceladus are largely named after characters in the Arabian Nights. Thus we have Aladdin, Ali Baba, and Sinbad, as well as Shaharazad crater. Until the Voyager spacecraft's encounter with the Uranian system, moons there were named after Shakespearean fairies, but are now named after Shakespearean characters in general. It was in this regard that I had occasion to learn firsthand how moons are named. I was an associate member of the Voyager imaging team during the 1986 first encounter with the Uranian planetary system. Before the encounter five Uranian moons were known, and 8 rings had been discovered by airborne astronomy. (The Kuiper airborne observatory had flown in the path of Uranus' motion watching a star pass behind the planet Uranus with an idea toward understanding, for example, the depth of its atmosphere, but had found the star flashing on and off on either side of the planet as well which was due to the ring material on either side).

A colleague of mine, Bruno Sicardy (of Observatoire de Paris) and I noticed that on a particular long exposure of the rings of Uranus taken by the Voyager spacecraft that one of the stars did not seem to be moving in the same direction as the others. "That's a new moon" we said, but our colleagues doubted this, indicating that it was probably one of the known moons or that perhaps we had mistaken its motion. With the help of navigation calculations done by Steve Synott at Jet Propulsion Laboratory (one of the navigation team), we obtained a prediction as to when the moon, if real, would be seen in any additional pictures coming in from the Voyager imaging system. If real, such images would appear again going across the field of view in the pictures being transmitted the very next morning. I got caught up in traffic early the next day, but when I got in folks on the Voyager Imaging Team greeted me with, "Congratulations! You've discovered a new moon!" Yippee! Bruno and I had discovered whole new tiny little world!

We called my brother, who was well acquainted with Shakespearean literature, and the decision for a suggested name rested between "Mab" and "Peaseblossom" both fairies from Shakespeare's "A Midsummer Nights Dream". We suggested the name "Peaseblossom" then, which was well received by the scientists on the Voyager imaging team. Ah, but a controversy arose about the names of the new Uranian moons when a congressman, a few weeks later, suggested that the newly discovered moons of Uranus be named after deceased astronauts --a suggestion that soon drew a reply from the then Soviet Union pointing out that naming them after deceased cosmonauts was equally valid. This, then, actually started a bit of an international scuffle! Thus no name was assigned to our little "Peaseblossom" for several years. Finally the name "Bianca", a Shakespearean character from Taming of the Shrew, was quietly chosen by the IAU committee on naming moons and in the Smithsonian Institution in Washington D.C. you will see that the Voyager spacecraft is (really rightly so) credited with discovery of a little Uranian moon named "Bianca" about 20 kilometers across.

Ah well, I still like the name "Peaseblossom" and nothing, to my knowledge, is yet named "Peaseblossom" in the heavens. However, Shakespeare is still a daily part of my life, as I have named the computer on my desk "Peaseblossom." It is there to remind me that Bruno and I were the first ever to know of a wholly new little world. And when I remember the thrill of that discovery, by any other name, it still smells as sweet. Subscribe To SPACE.com Planet Uranus: Facts About Its Name, Moons and Orbit Planet Uranus: Facts About Its Name, Moons and Orbit By Charles Q. Choi, Space.com Contributor | November 18, 2014 09:17pm ET MORE Uranus’ tilt essentially has the planet orbiting the Sun on its side, the axis of its spin is nearly pointing at the Sun. Credit: NASA and Erich Karkoschka, U. of Arizona Uranus is the seventh planet from the sun and the first to be discovered by scientists.

Although Uranus is visible to the naked eye, it was long mistaken as a star because of the planet’s dimness and slow orbit. The planet is also notable for its dramatic tilt, which causes its axis to point nearly directly at the sun. British astronomer William Herschel discovered Uranus accidentally on March 13, 1781, with his telescope while surveying all stars down to those about 10 times dimmer than can be seen by the naked eye. One "star" seemed different, and within a year Uranus was shown to follow a planetary orbit. Uranuswas named after the Greek sky deity Ouranos, the earliest of the lords of the heavens. It is the only planet to be named after a Greek god rather than a Roman one. Before the name was settled on, many names had been proposed for the new planet , including Hypercronius ("above Saturn"), Minerva (the Roman goddess of wisdom), and Herschel, after its discoverer. To flatter King George III of England, Herschel himself offered Georgium Sidus ("The Georgian Planet") as a name, but that idea was unpopular outside of England and George's native Hanover.

German astronomer Johann Bode, who detailed Uranus' orbit, gave the planet its ultimate name. [ Related: How Do You Pronounce 'Uranus'? ] Physical characteristics Uranusis blue-green in color , the result of methane in its mostly hydrogen-helium atmosphere. The planet is often dubbed an ice giant, since 80 percent or more of its mass is made up of a fluid mix of water, methane, and ammonia ices. Unlike the other planets of the solar system, Uranus is tilted so far that it essentially orbits the sun on its side, with the axis of its spin nearly pointing at the star. This unusual orientation might be due to a collision with a planet-size body, or several small bodies , soon after it was formed. This unusual tilt gives rise to extreme seasons roughly 20 years long, meaning that for nearly a quarter of the Uranian year, equal to 84 Earth-years, the sun shines directly over each pole, leaving the other half of the planet to experience a long, dark, cold winter.

The magnetic poles of most planets are typically lined up with the axis along which it rotates, but Uranus' magnetic field is tilted, with its magnetic axis tipped over nearly 60 degrees from the planet's axis of rotation. According to Norman F. Ness, et al, in an article in the journal Science, this leads to a strangely lopsided magnetic field for Uranus, with the strength of the field at the northern hemisphere's surface being up to more than 10 times that of the strength at the southern hemisphere's surface, affecting the formation of the auroras . Orbital characteristics Average distance from the sun: 1,783,939,400 miles (2,870,972,200 kilometers). By comparison: 19.191 times that of Earth Perihelion (closest approach to the sun): 1,699,800,000 miles (2,735,560,000 km).

By comparison: 18.60 times that of Earth Aphelion (farthest distance from sun): 1,868,080,000 miles (3,006,390,000 km). By comparison: 19.76 times that of Earth Composition & structure Atmospheric composition (by volume): 82.5 percent hydrogen, 15.2 percent helium, 2.3 percent methane Magnetic field: Magnetic pole tilt compared to rotational axis: 58.6 degrees Composition: The overall composition of Uranus is, by mass, thought to be about 25 percent rock, 60 to 70 percent ice, and 5 to 15 percent hydrogen and helium. Internal structure: Mantle of water, ammonia and methane ices; core of iron and magnesium-silicate Orbit & rotation Axial tilt: 97.77 degrees, compared to Earth's 23.5 degrees Seasonal cycle & length: Approximately 21 years per season Orbital period: Approximately 84 Earth years Uranus' climate The extreme axial tilt Uranus experiences can give rise to unusual weather.

As sunlight reaches some areas for the first time in years, it heats up the atmosphere, triggering gigantic springtime storms roughly the size of North America, according to NASA. Ironically, when Voyager 2 first imaged Uranus in 1986 at the height of summer in its south, it saw a bland-looking sphere with only about 10 or so visible clouds, leading to it to be dubbed "the most boring planet," writes astronomer Heidi Hammel in "The Ice Giant Systems of Uranus and Neptune," a chapter in " Solar System Update " (Springer, 2007). It took decades later, when advanced telescopes such as Hubble came into play and the seasons changed, to see extreme weather on Uranus , where fast-moving winds can reach speeds of up to 560 miles (900 kilometers) per hour. The rings of Uranus The rings of Uranus were the first to be seen after Saturn's. They were a significant discovery, because it helped astronomers understand that rings are a common feature of planets, not merely a peculiarity of Saturn. Uranus possesses two sets of rings .

The inner system of rings consists mostly of narrow, dark rings, while an outer system of two more-distant rings, discovered by the Hubble Space Telescope, are brightly colored, one red, one blue . Scientists have now identified 13 known rings around Uranus. Uranus' moons Uranus has 27 known moons . Instead of being named after figures from Greek or Roman mythology, its first four moons were named after magical spirits in English literature, such as William Shakespeare's "A Midsummer Night's Dream" and Alexander Pope's "The Rape of the Lock." Since then, astronomers have continued this tradition, drawing names for the moons from the works of Shakespeare or Pope. Oberon and Titania are the largest Uranian moons, and were the first to be discovered, by Herschel in 1787. William Lassell, who was the first to see a moon orbiting Neptune, discovered the next two, Ariel and Umbriel. Then nearly a century passed before Miranda was found in 1948.

Then, Voyager 2 visited the Uranian system in 1986 and found an additional 10 , all just 16 to 96 miles (26-154 km) in diameter — Juliet, Puck, Cordelia, Ophelia, Bianca, Desdemona, Portia, Rosalind, Cressida and Belinda — and each roughly made half of water ice and half of rock. Since then, astronomers using the Hubble Space Telescope and ground-based observatories have raised the total to 27 known moons, and spotting these was tricky — they are as little as 8 to 10 miles (12 to 16 km) across, blacker than asphalt, and nearly 3 billion miles (4.8 billion km) away. Between Cordelia, Ophelia and Miranda is a swarm of eight small satellites crowded together so tightly that astronomers don't yet understand how the little moons have managed to avoid crashing into each other. Scientists suspect there might still be more moons, closer to Uranus than any known.

In addition to moons, Uranus may also have a collection of Trojan asteroids — objects that share the same orbit as the planet — in a special region known as a Lagrangian point. The first was discovered in 2013 , despite claims that the planet’s Langrangian point would be too unstable to host such bodies. Research & exploration NASA's Voyager 2 was the first and as yet only spacecraft to visit Uranus. It discovered 10 previously unknown moons, and investigated its unusually tilted magnetic field. In 2013, the Planetary Science Decadal Survey recommended NASA consider a mission to the icy planet. Additional reporting by Nola Taylor Redd, Space.com Contributor The butt of solar system jokes, Uranus is also a spectacular blue planet still hiding many scientific secrets. See how much you know: Solar System Exploration – Uranus | Planet Simon Solar System Exploration – Uranus Simon 29 Comments We’re really getting far away from the sun now as our exploration takes us to Uranus. Uranus is the first planet to have been discovered in relatively modern times with a telescope. It was discovered by William Hershel in 1781 who at first thought he had discovered a comet.

Uranus is the ancient deity God of the sky Ouranos, in Greek mythology. Father of Cronos (Saturn) and grandfather of Zeus (Jupiter). Uranus is composed of an icy / metallic core and a helium / hydrogen atmosphere. The exact composition is not exactly known, but between 9 x and 13 x Earth’s mass makes up it’s core, the little remaining mass is it’s atmosphere. Some of the key facts about Uranus and how it compares with Earth: Diameter 50.700km (4 x Earth’s) 1 Uranus Day = 17h 14m hours long. 1 Uranus year = 84 years. Atmosphere = 96% Hydrogen, 3.2% Helium. Volume = 63 times that of Earth. Distance from the Sun = 20.11 x further than Earth. Uranus has 27 known moons. Mass is over 14 x Earths mass, but spread over a larger object. Uranus’s magnetic field extends at right angles to the other planets. Discovered in 1851 by William Lassell, Ariel is named after two characters in literature.

Composed mainly of rock and ice Ariel is 1,150km across. Several different terrain types have been identified on Ariel, Ridged, cratered and plains, each of these giving clues to the age of the different terrains and how the moon was formed. Umbriel Umbriel was also discovered in 1851 by William Lassell, named after a character in the poem The Rape of the Lock by Alexander pope. Umbriel is the darkest Uranus’s moons, again it’s made of rock and ice, it’s the most heavily impacted of the moons and this has a lot to do with how the surface was made. At 1,160km wide it’s Uranus’s third largest moon and the third furthest from Uranus. Titania Titania was discovered in 1787 by William Herschel, is named after the queen of the fairies in A Midsummer Nights Dream. Titania is the largest of Uranus’s moons at 1,578km and the 8th largest in the solar system. Titania’s surface seems relatively less damaged by craters, this could be due to a surface melting that occurred, obliterating the old surface.

Oberon Titania was discovered in 1787 by William Herschel, is named after the king of the fairies in A Midsummer Nights Dream. Oberon is 1,522km in diameter, the second largest of Uranus’s moons, it’s heavily cratered with an apparent slight red tint. Like all the other moons, it’s made mainly of rock and ice and is the furthers from Uranus. Rings Uranus has rings, like all the outer planets. They were discovered from Earth in an unusual way though. An airborne telescope flying over the pacific was using Uranus occultation of a star to make observations of it’s atmosphere. When the signal started dipping they thought that instrument faults had ruined their data. It was only after comparing the data before and after the occultation that they realised the ring dips were symmetrical – that had found the rings of Uranus. Inspiration The piece that Holst composed for Uranus is unusual to me, I’m not sure what the images were in his mind when it was written. But nonetheless, like a magician it didn’t give up it’s secrets easily and still doesn’t.

Recent Events Voyager 2 is to date the only human space craft to have visited Uranus. It flew past the planet in 1986, using the planet’s gravity to guide it towards it’s final destination of Neptune. On it’s approach to Uranus the scientist were expecting to be able to see more detail in the atmosphere as the probe approached. Even at a close distance Uranus’s atmosphere is virtually featureless. Only a few storms at very close range yielded any detail. This was the view of the planet on it’s approach, the rings were not visible as they are faint. Voyager passed by Uranus and used it’s gravity to fling it towards Neptune, it’s final destination in this solar system. To date Uranus has not been visited again by a human spacecraft, many of it’s secrets are yet to be discovered or solved. Simon 🙂 Planetary Names: Planet and Satellite Names and Discoverers International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN) Planetary Names: Planet and Satellite Names and Discoverers Home Named Mercurius by the Romans because it appears to move so swiftly. Discoverer Venus Roman name for the goddess of love.

This planet was considered to be the brightest and most beautiful planet or star in the heavens. Other civilizations have named it for their god or goddess of love/war. Discoverer Earth The name Earth comes from the Indo-European base 'er,'which produced the Germanic noun 'ertho,' and ultimately German 'erde,' Dutch 'aarde,' Scandinavian 'jord,' and English 'earth.' Related forms include Greek 'eraze,' meaning 'on the ground,' and Welsh 'erw,' meaning 'a piece of land.' Earth I (Moon) Every civilization has had a name for the satellite of Earth that is known, in English, as the Moon. The Moon is known as Luna in Italian, Latin, and Spanish, as Lune in French, as Mond in German, and as Selene in Greek. Martian System The names of the moons of Mars and the English translations of the names were specifically proposed by their discoverer, Asaph Hall, and as such, they have been accepted and retained under the current IAU nomenclature. Body Discoverer Mars Named by the Romans for their god of war because of its red, bloodlike color.

Other civilizations also named this planet from this attribute; for example, the Egyptians named it "Her Desher," meaning "the red one." Mars I (Phobos) Inner satellite of Mars. Named for one of the horses that drew Mars' chariot; also called an "attendant" or "son" of Mars, according to chapter 15, line 119 of Homer's "Iliad." This Greek word means "flight." August 17, 1877 A. Hall Mars II (Deimos) This outer Martian satellite was named for one of the horses that drew Mars' chariot; also called an "attendant" or "son" of Mars, according to chapter 15, line 119 of Homer's "Iliad." Deimos means "fear" in Greek. August 11, 1877 Selected Asteroids (of the Main Belt) and their Satellites Body Named for the Greek god of love. August 13, 1898 Named for a resort on the Crimean Peninsula. July 30, 1916 G.

Neujmin (243) Ida Named for a nymph who raised the infant Zeus. Ida is also the name of a mountain on the island of Crete, the location of the cave where Zeus was reared. September 29, 1884 J. Palisa (243) Ida I (Dactyl) Named for a group of mythological beings who lived on Mount Ida, where the infant Zeus was hidden and raised (according to some accounts) by the nymph Ida. August 28, 1993 Galileo imaging and infrared science teams. (253) Mathilde The name was suggested by a staff member of the Paris Observatory who first computed an orbit for Mathilde. The name is thought to honor the wife of the vice director of the Paris Observatory at that time. November 12, 1885 J. Palisa (22) Kalliope I (Linus) Satellite of (22) Kalliope. In various accounts of Greek mythology, Linus is considered to be the son of the Muse Kalliope and the inventor of melody and rhythm.

August 29 and September 2, 2001 Mauna Kea J.-L. Margot, M.E. Brown, W.J. Merline, F. Menard, L. Close, C. Dumas, C.R. Chapman, and D.C. Slater (45) Eugenia I (Petit-Prince) Satellite of (45) Eugenia. The Little Prince, Napolean-Eugene-Louis-Jean-Joseph Bonaparte (1856-1879), was the son of Eugenia de Montijo de Guzm\'an and Napoleon III. November 1, 1998 Mauna Kea W.J. Merline, L. Close, C. Dumas, C.R. Chapman, F. Roddier, F. Menard, D.C. Slater, G. Duvert, C. Shelton, and T. Morgan Jovian System Satellites in the Jovian system are named for Zeus/Jupiter's lovers and descendants.

Names of outer satellites with a prograde orbit generally end with the letter "a" (although an "o" ending has been reserved for some unusual cases), and names of satellites with a retrograde orbit end with an "e." Body Discoverer Jupiter The largest and most massive of the planets was named Zeus by the Greeks and Jupiter by the Romans; he was the most important deity in both pantheons. Jupiter I (Io) Io, the daughter of Inachus, was changed by Jupiter into a cow to protect her from Hera's jealous wrath. But Hera recognized Io and sent a gadfly to torment her. Io, maddened by the fly, wandered throughout the Mediterranean region. January 8, 1610 Padua Galileo (Simon Marius probably made an independent discovery of the Galilean satellites at about the same time that Galileo did, and he may have unwittingly sighted them up to a month earlier, but the priority must go to Galileo because he published his discovery first.) Jupiter II (Europa) Beautiful daughter of Agenor, king of Tyre, she was seduced by Jupiter, who had assumed the shape of a white bull.

When Europa climbed on his back he swam with her to Crete, where she bore several children, including Minos. January 8, 1610 Galileo (who evidently observed the combined image of Io and Europa the previous night) Jupiter III (Ganymede) Beautiful young boy who was carried to Olympus by Jupiter disguised as an eagle. Ganymede then became the cupbearer of the Olympian gods. January 7, 1610 Galileo Jupiter IV (Callisto) Beautiful daughter of Lycaon, she was seduced by Jupiter, who changed her into a bear to protect her from Hera's jealousy. January 7, 1610 Galileo Jupiter V (Amalthea) A naiad who nursed the new-born Jupiter. She had as a favorite animal a goat which is said by some authors to have nourished Jupiter. The name was suggested by Flammarion. September 9, 1892 A Rhodian nymph who bore three sons of Zeus. December 4, 1904 C.D.

Perrine Jupiter VII (Elara) Daughter of King Orchomenus, a paramour of Zeus, and by him the mother of the giant Tityus. January 3, 1905 C.D. Perrine Jupiter VIII (Pasiphae) Wife of Minos, king of Crete. Zeus made approaches to her as a bull (taurus). She then gave birth to the Minotaur. (Spelling changed from Pasiphaë to Pasiphae July 2009.) January 27, 1908 P.J. Melotte Jupiter IX (Sinope) Daughter of the river god Asopus. Zeus desired to make love to her. Instead of this he granted perpetual virginity, after he had been deceived by his own promises. (In the same way, she also fooled Apollo.) July 21, 1914 S.B. Nicholson Jupiter X (Lysithea) Daughter of Kadmos, also named Semele, mother of Dionysos by Zeus. According to others, she was the daughter of Evenus and mother of Helenus by Jupiter.

July 6, 1938 Daughter of the river god Achelous and stepdaughter of Zeus. October 19, 1999 J.V. Scotti, T.B. Spahr, R.S. McMillan, J.A. Larson, J. Montani, A.E. Gleason, and T. Gehrels Jupiter XVIII (Themisto) Daughter of the Arcadian river god Inachus, mother of Ister by Zeus. September 30, 1975, rediscovered November 21, 2000 Palomar, rediscovered at Mauna Kea C.T. Kowal and E. Roemer (1975), and S.S. Sheppard, D.C. Jewitt, Y.R. Fernandez, G. Magnier, M. Holman, B.G. Marsden, and G.V. Williams (2000). Jupiter XIX (Megaclite) Daughter of Macareus, who with Zeus gave birth to Thebe and Locrus. November 25, 2000 S.S. Sheppard, D.C.

Jewitt, Y.R. Fernandez, and G. Magnier Jupiter XX (Taygete) Daughter of Atlas, one of the Pleiades, mother of Lakedaimon by Zeus. November 25, 2000 S.S. Sheppard, D.C. Jewitt, Y.R. Fernandez, and G. Magnier Jupiter XXI (Chaldene) Bore the son Solymos with Zeus. November 26, 2000 S.S. Sheppard, D.C. Jewitt, Y.R. Fernandez, and G. Magnier Jupiter XXII (Harpalyke) Daughter and wife of Clymenus. In revenge for this incestuous relationship, she killed the son she bore him, cooked the corpse, and served it to Clymenus. She was transformed into the night bird called Chalkis, and Clymenus hanged himself. Some say that she was transformed into that bird because she had intercourse with Zeus. November 23, 2000 S.S. Sheppard, D.C. Jewitt, Y.R. Fernandez, and G.

Magnier Jupiter XXIII (Kalyke) Nymph who bore the handsome son Endymion with Zeus. November 23, 2000 S.S. Sheppard, D.C. Jewitt, Y.R. Fernandez, and G. Magnier Jupiter XXIV (Iocaste) Wife of Laius, King of Thebes, and mother of Oedipus. After Laius was killed, Iocaste unknowingly married her own son Oedipus. When she learned that her husband was her son, she killed herself. Some say she was the mother of Agamedes by Zeus. November 23, 2000 S.S. Sheppard, D.C. Jewitt, Y.R. Fernandez, and G. Magnier Jupiter XXV (Erinome) Daughter of Celes, compelled by Venus to fall in love with Jupiter. November 23, 2000 S.S. Sheppard, D.C. Jewitt, Y.R. Fernandez, and G. Magnier Jupiter XXVI (Isonoe) A Danaid, bore with Zeus the son Orchomenos.

November 23, 2000 S.S. Sheppard, D.C. Jewitt, Y.R. Fernandez, and G. Magnier Jupiter XXVII (Praxidike) Goddess of punishment, mother of Klesios by Zeus. November 23, 2000 S.S. Sheppard, D.C. Jewitt, Y.R. Fernandez, and G. Magnier Jupiter XXVIII (Autonoe) Mother of the Graces by Zeus according to some authors. December 10, 2001 S.S. Sheppard, D.C. Jewitt and J. Kleyna Jupiter XXIX (Thyone) Semele, mother of Dionysos by Zeus. She received the name of Thyone in Hades by Dionysos before he ascended up with her from there to heaven. December 11, 2001 S.S. Sheppard, D.C. Jewitt and J. Kleyna Jupiter XXX (Hermippe) Consort of Zeus and mother of Orchomenos by him. December 9, 2001 S.S. Sheppard, D.C.

Jewitt and J. Kleyna Jupiter XXXI (Aitne) A Sicilian nymph, conquest of Zeus. December 9, 2001 S.S. Sheppard, D.C. Jewitt and J. Kleyna Jupiter XXXII (Eurydome) Mother of the Graces by Zeus, according to some authors. (Source: Cornutus: Theologiae Graecae compendium 15) December 9, 2001 S.S. Sheppard, D.C. Jewitt and J. Kleyna Jupiter XXXIII (Euanthe) The mother of the Graces by Zeus, according to some authors. December 11, 2001 S.S. Sheppard, D.C. Jewitt and J. Kleyna Jupiter XXXIV (Euporie) One of the Horae, a daughter of Zeus and Themis. December 11, 2001 S.S. Sheppard, D.C. Jewitt and J. Kleyna Jupiter XXXV (Orthosie) One of the Horae, a daughter of Zeus and Themis. December 11, 2001 S.S.

Sheppard, D.C. Jewitt and J. Kleyna Jupiter XXXVI (Sponde) One of the Horae (Seasons), daughter of Zeus. December 9, 2001 S.S. Sheppard, D.C. Jewitt and J. Kleyna Jupiter XXXVII (Kale) One of the Graces, a daughter of Zeus, husband of Hephaistos. December 9, 2001 S.S. Sheppard, D.C. Jewitt and J. Kleyna Jupiter XXXVIII (Pasithee) One of the Graces, a daughter of Zeus. December 11, 2001 S.S. Sheppard, D.C. Jewitt and J. Kleyna Jupiter XXXIX (Hegemone) One of the Graces, a daughter of Zeus. February 8, 2003 Discoverer Saturn Roman name for the Greek Cronos, father of Zeus/Jupiter. Other civilizations have given different names to Saturn, which is the farthest planet from Earth that can be observed by the naked human eye.

Most of its satellites were named for Titans who, according to Greek mythology, were brothers and sisters of Saturn. Saturn I (Mimas) Named by Herschel's son John in the early 19th century for a Giant felled by Hephaestus (or Ares) in the war between the Titans and Olympian gods. July 18, 1789 W. Herschel Saturn II (Enceladus) Named by Herschel's son John for the Giant Enceladus. Enceladus was crushed by Athene in the battle between the Olympian gods and the Titans. Earth piled on top of him became the island of Sicily. August 28, 1789 W. Herschel Saturn III (Tethys) Cassini wished to name Tethys and the other three satellites that he discovered (Dione, Rhea, and Iapetus) for Louis XIV. However, the names used today for these satellites were applied in the early 19th century by John Herschel, who named them for Titans and Titanesses, brothers and sisters of Saturn.

Tethys was the wife of Oceanus and mother of all rivers and Oceanids. March 21, 1684 Named by Pickering for one of the Titanesses. August 16, 1898 W.H. Pickering Saturn X (Janus) First reported (though with an incorrect orbital period) and named by A. Dollfus from observations in Dec. 1966, this satellite was finally confirmed in 1980. It was proven to have a twin, Epimetheus, sharing the same orbit but never actually meeting. It is named for the Roman god of the beginning. The two-faced god could look forward and backward at the same time. December 15, 1966 (Dollfus), February 19, 1980 (Pascu) Pic du Midi (Dollfus), Washington (Pascu) A. Dollfus (1966), D. Pascu (1980) Saturn XI (Epimetheus) First suspected by J. Fountain and S. Larson as confusing the detection of Janus.

They assigned the correct orbital period, and the satellite was finally confirmed in 1980. Named for the son of the Titan Iapetus. In contrast with his far-sighted brother Prometheus, he "subsequently realized" that he was in the wrong. 1977 (Fountain and Larson), February 26, 1980 (Cruikshank) Tucson (Fountain and Larson), Mauna Kea (Cruikshank) J. Fountain and S. Larson (1977), D. Cruikshank (1980) Saturn XII (Helene) A granddaughter of Kronos, for her beauty she triggered off the Trojan War. March 1, 1980 P. Laques and J. Lecacheux Saturn XIII (Telesto) Daughter of the Titans Oceanus and Tethys. April 8, 1980 B.A. Smith, H. Reitsema, S.M. Larson, and J. Fountain Saturn XIV (Calypso) Daughter of the Titans Oceanus and Tethys and paramour of Odysseus.

March 13, 1980 D. Pascu, P.K. Seidelmann, W. Baum, and D. Currie Saturn XV (Atlas) A Titan; he held the heavens on his shoulders. October 1980 Voyager Science Team Saturn XVI (Prometheus) Son of the Titan Iapetus, brother of Atlas and Epimetheus, he gave many gifts to humanity, including fire. October 1980 Voyager Science Team Saturn XVII (Pandora) Made of clay by Hephaestus at the request of Zeus. She married Epimetheus and opened the box that loosed a host of plagues upon humanity. October 1980 Voyager Science Team Saturn XVIII (Pan) Greek god of pastoralism, he was half goat and half human. Son of Hermes, brother of Daphnis, and a descendant of the Titans. Discovered orbiting in the Encke division in Saturn's A ring. 1990 Ymir is the primordial Norse giant and the progenitor of the race of frost giants. August 7, 2000 La Silla B. Gladman, J. Kavelaars, J.-M.

Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A. Burns Saturn XX (Paaliaq) Named for an Inuit giant. August 7, 2000 La Silla B. Gladman, J. Kavelaars, J.-M. Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A. Burns Saturn XXI (Tarvos) Named for a Gallic giant. September 23, 2000 Mauna Kea B. Gladman, J. Kavelaars, J.-M. Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A. Burns Saturn XXII (Ijiraq) Named for an Inuit giant. September 23, 2000 Mauna Kea B. Gladman, J. Kavelaars, J.-M. Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A.

Burns Saturn XXIII (Suttungr) Named for a Norse giant who kindled flames that destroyed the world. September 23, 2000 Mauna Kea B. Gladman, J. Kavelaars, J.-M. Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A. Burns Saturn XXIV (Kiviuq) Named for an Inuit giant. August 7, 2000 La Silla B. Gladman, J. Kavelaars, J.-M. Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A. Burns Saturn XXV (Mundilfari) Named for an Norse giant. September 23, 2000 Mauna Kea B. Gladman, J. Kavelaars, J.-M. Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A.

Burns Saturn XXVI (Albiorix) Named for a Gallic giant who was considered to be the king of the world. November 9, 2000 Named for a Norse giantess. September 23, 2000 Mauna Kea B. Gladman, J. Kavelaars, J.-M. Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A. Burns Saturn XXVIII (Erriapus) Named for a Gallic giant. September 23, 2000 Mauna Kea B. Gladman, J. Kavelaars, J.-M. Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A. Burns Saturn XXIX (Siarnaq) Named for an Inuit giant. September 23, 2000 Mauna Kea B. Gladman, J. Kavelaars, J.-M. Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A.

Burns Saturn XXX (Thrymr) Named for a Norse giant. September 23, 2000 Mauna Kea B. Gladman, J. Kavelaars, J.-M. Petit, H. Scholl, M. Holman, B.G. Marsden, P. Nicholson and J.A. Burns Saturn XXXI (Narvi) Named for a Norse giant. February 5, 2003 S.S. Sheppard, D.C. Jewitt, and J. Kleyna Saturn XXXII (Methone) One of the Alkyonides, the seven beautiful daughters of the Giant Alkyoneos. June 1, 2004 S. Sheppard, D.C. Jewitt, J. Kleyna Saturn XXXVIII (Bergelmir) Norse frost giant, son of Ymir and one of the Hrimthursar, one of only two members of the frost giant race to escape being drowned in Ymir's blood. December 12, 2004 S. Sheppard, D.C. Jewitt, J.

Kleyna Saturn XXXIX (Bestla) Norse primeval goddess, mother of deities, daughter of the giant Bolthorn. December 13, 2004 S. Sheppard, D.C. Jewitt, J. Kleyna Saturn XL (Farbauti) Norse storm giant, father of Loki. December 12, 2004 S. Sheppard, D.C. Jewitt, J. Kleyna Saturn XLI (Fenrir) Norse monstrous wolf, son of Loki and the giantess Angurboda, father of Hati and Skoll. December 13, 2004 S. Sheppard, D.C. Jewitt, J. Kleyna Saturn XLII (Fornjot) Early Norse storm giant, father of Aegir, Kari, and Loge. December 12, 2004 S. Sheppard, D.C. Jewitt, J. Kleyna Saturn XLIII (Hati) Gigantic Norse wolf, twin of Skoll. December 12, 2004 S. Sheppard, D.C. Jewitt, J.

Kleyna Saturn XLIV (Hyrrokkin) Norse giantess who launched Balder's funeral ship. (Spelling changed from Hyrokkin.) December 12, 2004 S. Sheppard, D.C. Jewitt, J. Kleyna Saturn XLV (Kari) Named for the grotesque, brutish slave in Shakespeare's "The Tempest." September 6, 1997 B. Gladman, P. Nicholson, J.A. Burns and J. Kavelaars Uranus XVII (Sycorax) Named for Caliban's mother in Shakespeare's "The Tempest." September 6, 1997 P. Nicholson, B. Gladman, J. Burns and J. Kavelaars Uranus XVIII (Prospero) Named for the rightful Duke of Milan in "The Tempest." July 18, 1999 M. Holman, J. Kavelaars, B. Gladman, J.-M. Petit, and H.

Scholl Uranus XIX (Setebos) Setebos was a new-world (South American) deity's name that Shakespeare popularized as Sycorax's god in "The Tempest." July 18, 1999 J. Kavelaars, B. Gladman, M. Holman, J.-M. Petit, and H. Scholl Uranus XX (Stephano) Named for a drunken butler in "The Tempest." July 18, 1999 B. Gladman, M. Holman, J. Kavelaars, J.-M. Petit, and H. Scholl Uranus XXI (Trinculo) A jester in Shakespeare's "The Tempest." August 13, 2001 M. Holman, J.J. Kavelaars and D. Milisavljevic Uranus XXII (Francisco) A lord in "The Tempest." August 13, 2001 J. Kavelaars, M. Holman, D. Milisavljevic, and T.

Grav Uranus XXIII (Margaret) A gentlewoman attending on Hero from "Much Ado About Nothing." August 29, 2003 Discoverer Neptune Neptune was "predicted" by John Couch Adams and Urbain Le Verrier who, independently, were able to account for the irregularities in the motion of Uranus by correctly predicting the orbital elements of a trans- Uranian body. Using the predicted parameters of Le Verrier (Adams never published his predictions), Johann Galle observed the planet in 1846. Galle wanted to name the planet for Le Verrier, but that was not acceptable to the international astronomical community. Instead, this planet is named for the Roman god of the sea. September 23, 1846 J.G. Galle Neptune I (Triton) Triton is named for the sea-god son of Poseidon (Neptune) and Amphitrite. The first suggestion of the name Triton has been attributed to the French astronomer Camille Flammarion. October 10, 1846 W.

Lassell Neptune II (Nereid) The Nereids were the fifty daughters of the sea god Nereus and Doris and were attendants of Poseidon (Neptune). May 1, 1949 G.P. Kuiper Neptune III (Naiad) The name of a group of Greek water nymphs who were guardians of lakes, fountains, springs, and rivers. August 1989 One of the Nereids, the fifty daughters of Nereus and Doris. August 14, 2002 M. Holman, J. Kavelaars, T. Grav, W. Fraser, and D. Milisavljevic Neptune X (Psamathe) One of the Nereids, lover of Aeacus and mother of Phocus. August 29, 2003 S.S. Sheppard, D.C. Jewitt, and J. Kleyna Neptune XI (Sao) One of the Nereids, the fifty daughters of Nereus and Doris. August 14, 2002 T. Grav, M. Holman, J. Kavelaars, W.

Fraser, and D. Milisavljevic Neptune XII (Laomedeia) One of the Nereids, the fifty daughters of Nereus and Doris. August 13, 2002 J. Kavelaars, M. Holman, T. Grav, W. Fraser, and D. Milisavljevic Neptune XIII (Neso) One of the Nereids, the fifty daughters of Nereus and Doris. August 14, 2002 Discoverer (134340) Pluto Pluto was discovered at Lowell Observatory in Flagstaff, AZ during a systematic search for a trans-Neptune planet predicted by Percival Lowell and William H. Pickering. Named after the Roman god of the underworld who was able to render himself invisible. January 23, 1930 C.W. Tombaugh (134340) Pluto I (Charon) Named after the Greek mythological boatman who ferried souls across the river Styx to Pluto for judgement. April 13, 1978 J.W.

Christy (134340) Pluto II (Nix) Goddess of darkness and night, mother of Charon. (Nix is the Egyptian spelling of the Greek name Nyx.) May 15, 2005 Hubble Space Telescope H.A. Weaver, S.A. Stern, M.J. Mutchler, A.J. Steffl, M.W. Buie, W.J. Merline, J.R. Spencer, E.F. Young, and L.A. Young (134340) Pluto III (Hydra) In Greek mythology, terrifying monster with the body of a serpent and nine heads that guarded the underworld. May 15, 2005 Hubble Space Telescope H.A. Weaver, S.A. Stern, M.J. Mutchler, A.J. Steffl, M.W. Buie, W.J. Merline, J.R. Spencer, E.F. Young, and L.A. Young (134340) Pluto IV (Kerberos) In Greek mythology, the many-headed dog that guarded the entrance to the underworld. June 28, 2011 M.R.

Showalter, D.P. Hamilton, S.A. Stern, H.A. Weaver, A.J. Steffl, and L.A. Young (134340) Pluto V (Styx) 1000+ images about Planet Uranus on Pinterest | Largest planet, Solar system and Pictures of Forward Time-lapse Voyager 2 images of Uranus show the movement of two small, bright, streaky clouds -- the first such features ever seen on the planet. The clouds were detected in this series of orange-filtered images taken Jan. 14, 1986, over a 4.6-hour interval (from top to bottom). At the time, the spacecraft was about 12.9 million kilometers (8.0 million miles) from the planet, whose pole of rotation is near the center of each disk. 1 ASP: Next Stop: Uranus © 1986, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112 Next Stop: Uranus On January 24, 1986.

the aging but still active Voyager 2 spacecraft will become the first mission to fly by the seventh planet in our solar system. a giant, bluish-green, and often puzzling world called Uranus. Mission scientists predict that we will learn more about this distant planet in the six hours of closest encounter than we have in the roughly 200 years since Uranus was discovered. In this issue of The Universe in the Classroom , we summarize our current knowledge of the complex Uranus system and provide some background to help you evaluate and explain the Voyager results to your classes. History Uranus was the first planet to be discovered that was not known to the ancients. It was found on March 13, 1781 by an amateur astronomer (and professional musician) named William Herschel, using a homemade 6.2-inch telescope. At first Herschel thought he had merely discovered a new comet, but it soon became apparent that the new object behaved like a planet. After some debate it was named Uranus, after the god in Greek mythology who most closely personified the heavens.

(Uranus was the father of the Titans and thus grandfather of Jupiter.) As a result of his pioneering find, Herschel received a life-long stipend from the king of England and was able to continue building larger and larger telescopes and making a host of important discoveries. Among these was his spotting of two of Uranus's moons, Titania and Oberon, in 1787. (Uranus's satellites are the only ones in the solar system not named after figures in Greek and Roman mythology; instead they are named for characters in English literature. Oberon and Titania are the rulers of the fairies in Shakespeare's A Midsummer Night's Dream.) Two further moons were discovered by the British astronomer William Lassell in 1851 and named Ariel and Umbriel, after characters in Alexander Pope's Rape of the Lock. (Ariel is also a figure in Shakespeares The Tempest.) Uranus's fifth moon was not discovered until 1948. when the noted American astronomer Gerard Kuiper used an 82-inch telescope in Texas to distinguish its faint light. It is called Miranda after another character in The Tempest.

In 1977 a team of astronomers led by James Elliot of MIT discovered an extremely faint system of rings encircling Uranus. Flying aboard a jet aircraft equipped with a sizeable telescope, they found the rings by watching the Uranus system pass in front of a star. As expected, when the disk of the planet was in front of the star, the starlight was blocked (or eclipsed). Unexpectedly, the astronomers also saw several brief eclipses before and after Uranus was scheduled to cover the star. After careful analysis of their data, they surmised that the starlight was being alternately hidden and revealed by several thin, dark rings. Uranus's Rings and Moons from Earth This picture is the first visible-light image to show the rings of Uranus. It was produced in 1984 by Drs. Bradford Smith of the University of Arizona and Richard Terrile of NASA's Jet Propulsion Laboratory. They used the Carnegie Institution of Washington's 2.5-meter (100-inch) du Pont telescope high in the Chilean Andes, equipped with an electronic camera, to register the original image.

The data recorded by the camera were then computer processed at the Jet Propulsion Laboratory to bring out details which would have been undetectable if the image had been recorded by conventional photographic means. We view the Uranus system nearly pole-on now, because Uranus's spin axis is tilted by about 90 degrees relative to its orbit path and since it is in a part of its orbit where one pole is pointed almost directly toward the Sun and the inner planets (including Earth). The rings and satellites orbit around the plane above its equator, so we see them surrounding Uranus spread out like this. Notice that the ring system is more distinct at lower-right than elsewhere; this is because — unlike Saturn's rings — Uranus's are broader on one side than on the other. JPL computer-processing created the false "three-dimensional'' effect, which helps make the very dark rings stand out clearly, even though they are close to the much brighter planet. The vertical lines are due to minor defects in the detector. (Photograph courtesy of NASA.) Uranus: The Planet Uranus is one of the giant planets in the solar system, a designation it shares with Jupiter, Saturn, and its more distant neighbor, Neptune.

It is a bluish-green globe about 51,000 kilometers (31,000 miles) in diameter, some four times the size of our Earth. In three dimensions, some 64 Earths could fit into the volume of the giant planet. Uranus is more than 19 times farther from the Sun than our Earth, taking about 84 Earth years to circle our star. Its average distance from the Sun is 1.8 billion miles, so large that when Herschel discovered the planet it almost doubled the size of the known solar system. As a result of its remoteness, the amount of sunlight reaching Uranus is very small indeed — only about 1/400th the intensity of the sunlight we enjoy on Earth. This is a question of more than just academic interest, since the darkness will make it more difficult for Voyager's cameras to take photographs than it was at Jupiter or Saturn. Because we see planets only by the sunlight they reflect back to us, Uranus is always a faint object in our sky.

In a recent issue of Sky & Telescope magazine James Elliot calculates that the total amount of light astronomers have seen observing Uranus since 1781 is less than the light produced simply by turning on an average flashlight for one second. One of the most interesting features of Uranus's motion is that the planet is rotating "on its side.'' The planets in our solar system generally circle the Sun in a flat plane. If you imagine passing a thick (cosmic) sheet of paper through the Sun's equator, the orbits of the planets would be found more or less in that sheet. In addition to their motion about the Sun, the planets also spin on their axes, producing day and night. These axes are generally perpendicular to the plane of the solar system. Venus, for example, has an axis that points almost straight up and down; Earth's axis is tilted by 23 degrees. giving us our varying seasons. Uranus's axis is tilted by about 90 degrees from the vertical, meaning its axis lies more or less in the plane of the solar system — Uranus spins on its side. Right now Uranus's south pole is pointing almost directly at the Sun and its north pole is in complete darkness.

As the planet slowly circles the Sun, the part facing the Sun gradually changes. In 42 years, it will be the north pole that receives the feeble rays of the distant Sun and the south pole that is shrouded in darkness. We are not sure why Uranus rotates on its side. One idea is that early in the history of the solar system, one large chunk of forming matter or a number of smaller chunks collided with Uranus and tipped it over. But it is not easy trying to reconstruct events that occurred billions of years ago (and billions of miles away). Astronomers are also not sure how fast Uranus spins about its sideways axis — current estimates suggest about 16 Earth hours, but this number is very uncertain. We hope Voyager will soon give us the definitive answer to this question — and many others. The Rings Uranus's rings have been observed with the starlight-blocking (or occultation) technique 13 more times since they were discovered in 1977. We now know that there are at least nine narrow rings encircling the planet. They are not easy to see even with sophisticated modern techniques.

First of all, the whole system is very narrow — probably no more than 10,000 km (6000 miles) from the inner edge to the outer edge. By contrast, Saturn's main ring system is 70,000 km wide and some of its outer rings stretch another 100,000 km farther from the planet. Uranus's rings themselves vary in width from just 2 kilometers for the innermost rings, to almost 100 kilometers for the widest part of the ring. A second reason Uranus's rings are so hard to make out is that they are very very dark, reflecting little of the sparse sunlight they receive. For example, the outermost ring (called the epsilon ring) reflects only 5 percent of the light it receives. Furthermore, the rings all lie within 26,500 kilometers (16,500 miles) of the planet's comparative!y much brighter cloudtops. making their feeble light even more difficult to distinguish. Astronomers have learned a bit more about the rings by studying not their visible light, but the faint heat rays (infrared) they emit.

Once again, however, the close-up Voyager photos will help us sort out just how many rings there are and what their detailed properties might be. One noteworthy and fundamental puzzle is just how the rings, which are made up of many smaller particles orbiting together, maintain their thin structure without spreading out. One suggestion is that tiny moons on either side of each ring act as "shepherds'' holding the ring particles in their narrow orbits. Voyager investigators will be on the lookout for evidence of these shepherding satellites during the flyby. Uranus Characteristics * "Surface'' here means the cloudtops; Uranus may not have a solid surface at all. Uranus's Satellites The accompanying tab!e gives our best (pre-Voyager) estimates for the characteristics of Uranus's five known satellites. Overall, they appear some 2000 times fainter to us than the faintest star that can be seen with the naked eye, so it should not be surprising that we don't know a great deal about them. All are cold worlds, with the surface temperature never exceeding minus 190 degrees centigrade.

They vary in size from a chunk about the size of an asteroid to a world less than half of the size of our Moon. (It is interesting that Uranus is the only giant planet without a large moon; Jupiter, Saturn, and Neptune each have one or more satellites that are comparable in size to our Moon.) If the Voyager exploration of Jupiter and Saturn is any indication, we may well discover previously unknown satellites around Uranus during our brief visit. In fact, three astronomers at MIT have already predicted the existence of another satellite inside the orbit of Miranda (the innermost known moon) from the detailed study of the motion of the rings. We shall see how well their prediction comes out. One major challenge of the Voyager flyby involves the orientation of Uranus's moons Voyager is approaching the planet from the general direction of the Sun — the same direction Uranus's south pole now faces. The satellites, on the other hand, orbit about the equator of the planet. This means that as Voyager approaches its rendesvous, the orbits of the satellites will present a kind of bullseye to our spacecraft. Just like a bullet can only pierce a target in one place, so Voyager can only select one point in that bullseye to fly through.

(When Voyager passed by Jupiter and Saturn, it flew more along the plane of the satellites' orbits and was able to explore several moons in succession.) To get the best views of both the planet and some satellites. Voyager scientists have programmed the spacecraft to fly closest to the small inner moon Miranda. The plan calls for Voyager to pass within 29,000 kilometers (18,000 mi) of Miranda and within 81,000 km (51,000 mi) of Uranus's cloudtops. However, Voyager's cameras will be trained on all the other moons as well, even if the views will not be quite as detailed as our images of Miranda. Uranus's Satellites Bennett, G.: "Voyager 2 Encounter with Uranus'' in Astronomy, Sep.1985. Croswell, K.: "Uranus On the Eve of the Encounter'' in Astronomy Sep.1985. Cruikshank, D.: "Uranus: Distant Giant'' in The Planets, ed. B.

Preiss (1985, Bantam) Elliot, J.:"'Uranus: The View from Earth'' in Sky & Telescope, Nov.1985. Elliot, J.: "Discovering the Rings of Uranus'' in Sky & Telescope, June, 1977. Miner, E.: "Voyager 2 and Uranus'' in Sky & Telescope, Nov. 1985. History Alexander A.: The Planet Uranus: A History of Observations, Theory and Discovery, (1965, Faber & Faber) Bennett, J.: "The Discovery of Uranus'' in Sky & Telescope, Mar. 1981. << previous page | 1 | 2 | 3 | 4 | next page >>

Question: Which planet in the solar system has several moons named after characters in Shakespeare's 'A Midsummer- Night's Dream'?
Answer: URANUS