Uranus' "Frankenstein Moon" Miranda - Universe Today Universe Today by Matt Williams Ever since the Voyager space probes ventured into the outer Solar System, scientists and astronomers have come to understand a great deal of this region of space. In addition to the four massive gas giants that call the outer Solar System home, a great deal has been learned about the many moons that circle them. And thanks to photographs and data obtained, human beings as a whole have come to understand just how strange and awe-inspiring our Solar System really is. This is especially true of Miranda, the smallest and innermost of Uranus’ large moons – and some would say, the oddest-looking! Like the other major Uranian moons, its orbits close to its planet’s equator, is perpendicular to the Solar System’s ecliptic, and therefore has an extreme seasonal cycle. Combined with one of the most extreme and varied topographies in the Solar System, this makes Miranda an understandable source of interest! Discovery and Naming: Miranda was discovered on February 16th, 1948, by Gerard Kuiper using the McDonald Observatory ‘s Otto Struve Telescope at the University of Texas in Austin.

Its motion around Uranus was confirmed on March 1st of the same year, making it the first satellite of Uranus to be discovered in almost a century (the previous ones being Ariel and Umbriel, which were both discovered in 1851 by William Lassell). A montage of Uranus’s moons. Image credit: NASA/JPL Consistent with the names of the other moons, Kuiper decided to the name the object “Miranda” after the character in Shakespeare’s The Tempest. This continued the tradition set down by John Herschel, who suggested that all the large moons of Uranus – Ariel , Umbriel , Titania and Oberon – be named after characters from either The Tempest or Alexander Pope’s The Rape of the Lock. Size, Mass and Orbit: With a mean radius of 235.8 ± 0.7 km and a mass of 6.59 ± 0.75 ×1019 kg, Miranda is 0.03697 Earths times the size of Earth and roughly 0.000011 as massive.

Its modest size also makes it one of the smallest object in the Solar System to have achieved hydrostatic equilibrium , with only Saturn’s moon of Mimas being smaller. Of Uranus’ five larger moons, Miranda is the closest, orbiting at an average distance (semi-major axis) of 129,390 km. It has a very minor eccentricity of 0.0013 and an inclination of 4.232° to Uranus’ equator. This is unusually high for a body so close to its parent planet – roughly ten times that of the other Uranian satellites. Since there are no mean-motion resonances to explain this, it has been hypothesized that the moons occasionally pass through secondary resonances. At some point, this would have led Miranda into being locked in a temporary 3:1 resonance with Umbriel, and perhaps a 5:3 resonance with Ariel as well. This resonance would have altered the moon’s inclination, and also led to tidal heating in its interior (see below). Size comparison of all the Solar Systems moons.

Credit: NASA/The Planetary Society With an average orbital speed of 6.66 km/s, Miranda takes 1.4 days to complete a single orbit of Uranus. Its orbital period (also 34 hours) is synchronous with its rotational period, meaning that it is tidally-locked with Uranus and maintains one face towards it at all times. Given that it orbits around Uranus’ equator, which means its orbit is perpendicular to the Sun’s ecliptic, Uranus goes through an extreme seasonal cycle where the northern and southern hemispheres experience 42 years of lightness and darkness at a time. Composition and Surface Structure: Miranda’s mean density (1.2 g/cm3) makes it the least dense of the Uranian moons. It also suggests that Miranda is largely composed of water ice (at least 60%), with the remainder likely consisting of silicate rock and organic compounds in the interior. The surface of Miranda is also the most diverse and extreme of all moons in the Solar System, with features that appear to be jumbled together in a haphazard fashion.

This consists of huge fault canyons as deep as 20 km (12 mi), terraced layers, and the juxtaposition of old and young surfaces seemingly at random. This patchwork of broken terrain indicates that intense geological activity took place in Miranda’s past, which is believed to have been driven by tidal heating during the time when it was in orbital resonance with Umbriel (and perhaps Ariel). This resonance would have increased orbital eccentricity, and along with varying tidal forces from Uranus, would have caused warming in Miranda’s interior and led to resurfacing. In addition, the incomplete differentiation of the moon, whereby rock and ice were distributed more uniformly, could have led to an upwelling of lighter material in some areas, thus leading to young and older regions existing side by side. Uranus’ moon Miranda, imaged by the Voyager 2 space probe on January 24th, 1986. Credit: NASA/JPL-Caltech Another theory is that Miranda was shattered by a massive impact, the fragments of which reassembled to produce a fractured core.

In this scenario – which some scientists believe could have happened as many as five times – the denser fragments would have sunk deep into the interior, with water ice and volatiles setting on top of them and mirroring their fractured shape. Overall, scientists recognize five types of geological features on Miranda, which includes craters, coronae (large grooved features), regiones (geological regions), rupes (scarps or canyons) and sulci (parallel grooves). Miranda’s cratered regions are differentiated between younger, lightly-cratered regions and older, more-heavily cratered ones. The lightly cratered regions include ridges and valleys, which are separated from the more heavily-cratered areas by sharp boundaries of mismatched features. The largest known craters are about 30 km (20 mi) in diameter, with others lying in the range of 5 to 10 km (3 to 6 mi). Miranda has the largest known cliff in the Solar System, which is known as Verona Rupes (named after the setting of Shakespeare’s Romeo and Juliet).

This rupes has a drop-off of over 5 km (3.1 mi) – making it 12 times as deep as the Grand Canyon. Scientists suspect that Miranda’s ridges and canyons represent extensional tilt blocks – a tectonic event where tectonic plates stretch apart, forming patterns of jagged terrain with steep drops. Image taken by the Voyager 2 probe during its close approach on January 24th, 1986, with a resolution of about 700 m (2300 ft). Credit: NASA/JPL The most well known coronae exist in the southern hemisphere, with three giant ‘racetrack’-like grooved structures that measure at least 200 km (120 mi) wide and up to 20 km (12 mi) deep. These features, named Arden, Elsinore and Inverness – all locations in Shakespeare’s plays – may have formed via extensional processes at the tops of diapirs (aka. upwellings of warm ice). Other features may be due to cryovolcanic eruptions of icy magma, which would have been driven by tidal flexing and heating in the past.

With an albedo of 0.32, Miranda’s surface is nearly as bright as that of Ariel, the brightest of the larger Uranian moons. It’s slightly darker appearance is likely due to the presence of carbonaceous material within its surface ice. Exploration: Miranda’s apparent magnitude makes it invisible to many amateur telescopes. As a result, virtually all known information regarding its geology and geography was obtained during the only flyby of the Uranian system, which was made by Voyager 2 in 1986. During the flyby, Miranda’s southern hemisphere pointed towards the Sun (while the northern was shrouded in darkness), so only the southern hemisphere could be studied. At this time, no future missions have been planned or are under consideration. But given Miranda’s “Frankenstein”-like appearance and the mysteries that still surround its history and geology, any future missions to study Uranus and its system of moons would be well-advised. We have many interesting articles on Miranda and Uranus’ moons here at Universe Today. Here’s one about about why they call it the “ Frankenstein Moon “, and one about Voyager 2‘s historic flyby .

And here’s one that answers the question How Many Moons Does Uranus Have ? For more information, check out NASA’s Solar System Exploration page on Miranda . Share this: BW Color Prints | Science On a Sphere - Datasets Uranus’ Moons — Miranda, Ariel, Umbriel, Titania, Oberon Description: Uranus has 27 moons, all of which are named after characters in Shakespeare and Alexander Pope works. The five main satellites, in order of proximity to Uranus, are Miranda, Ariel, Umbriel, Titania, and Oberon. Before the Voyager 2 studied Uranus in 1986, these five moons were the only ones known to exist. Miranda Miranda (a character in The Tempest by Shakespeare) has a surface unlike any other in the solar system. One theory for the jumbled appearance is that the moon has shattered and reformed up to five times, creating a surface of both young and old material. Another explanation involves the upwelling of partially melted ices. Ariel Ariel (a character in The Tempest by Shakespeare and also a character in a Pope poem) is the brightest moon of Uranus.

The most notable features on this moon are the craters that cover the surface as well as the interconnected rift valleys that run across the moon. Some of the valleys are up to 6 miles deep. Umbriel Umbriel (a character in The Rape of the Lock by Pope) is the darkest moon of Uranus. It is also the least geologically active satellite with a heavily cratered surface indicating that it is old. Near the equator of Umbriel is a bright ring referred to the as the Fluorescent Cheerio or Wunda. The origin of this is unknown, though it is believed to be the floor of a crater. Titania Titania (Queen of the fairies in A Midsummer Night’s Dream by Shakespeare) has a surface remarkably similar to that of Ariel. Covered in craters and interconnected valleys like Ariel, Titania is 35% larger than Ariel and is the largest of the known satellites orbiting Uranus. One of the most notable features is a trench that extends for over 1000 miles. It is thought that the satellite was once hot and the valleys and trenches are the result of the planet freezing and expanding.

Oberon Oberon (King of the fairies in A Midsummer Night’s Dream by Shakespeare) is similar to Umbriel but 35% larger. Heavily cratered and geologically inactive, Oberon is the second largest moon of Uranus. In many of the large craters that cover the surface there is a dark material that coats the crater floors. It is still unknown what causes this. Also of interest on Oberon is a mountain that is over 4 miles tall. Data Category Umbriel - Our Solar System Our Solar System Moon's of Neptune Umbriel Umbriel [UM-bree-ul] is the thirteenth of Uranus' moons and the third largest. Umbriel was discovered by William Lassell in 1851. Since then it has been visited by one spacecraft, Voyager 2, which taught us nearly everything we know about this moon. The Fluorescent Cheerio As with all of Uranus' moons, Umbriel is believed to be composed of about 50% water ice and 50% rocky material. This composition is very similar to Saturn's moon, Rhea, but with a larger percentage of rock.

Umbriel is about the same size as Ariel and has nearly the same density. The most curious feature of Umbriel is a bright, ring-shaped area near to top of the moon. It has been called the "fluorescent cheerio" because of its round shape and bright color. This feature is believed to be floor of a crater. The impact that formed the crater may have exposed material from deeper in the moon's crust that has a different albedo from the surrounding dark material. Features of Umbriel Umbriel is an extremely dark moon. It reflects only about half as much light as Uranus' brightest moon, Ariel. Astronomers are not sure what accounts for Umbriel's dark color. The cratered surface of this moon is relatively featureless. This indicates that it has probably been geologically stable since its formation billions of years ago. Some of the craters are much brighter than the surrounding areas. As with the "fluorescent cheerio", these bright areas are believed to have been formed when recent impacts brought lighter material to the surface. Umbriel has no known atmosphere and no magnetic field. Statistics of Umbriel Uranus Moons Jupiter Facts Uranus Moons Uranus has 27 known moons (satellites).

All of it’s moons compositions are generally rock and ice. Uranus’s moons are generally categorized as the Inner Moons (13), Major Moons (5) and Irregular Moons (9). The Inner Moons are named Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Cupid, Belinda, Perdita, Puck and Mab. The Major Moons are named Miranda, Ariel, Umbriel, Titania and Oberon. The Irregular Moons are named Francisco, Caliban, Stephano, Trinculo, Sycorax, Margaret, Prospero, Setebos and Ferdinand. Some of these names may look familiar to you, a matter of fact, all of Uranus’s moons are named after characters from Alexander Pope and William Shakespeare works. Titania Uranus’s largest moon is Titania with a diameter of 1,577.8 km or 980 miles and a mass of 3.42 x 1021 kg. This makes it the eighth largest moon in our solar system (less than half the size of Earth’s moon).

Titania was discovered on January 11, 1787 by William Herschel. Its distance from Uranus is 436,300 km or 271,104 miles and takes 8.7 Earth days to make 1 complete orbit around Uranus. Titania’s orbit around Uranus is almost a perfect circle with the orbit eccentricity at 0.0011 and is closest (Periapsis) to the planet at 435,820 km or 270,805 miles and farthest (Apoapsis) from the planet at 436,780 km or 271,402 miles. The orbit inclination is only 0.079°, which means it’s North pole is getting about 42 years of straight sunlight and about 42 years of straight darkness. You’ll remember that Uranus is on its side so when the moons orbit the planet they are actually moving in a vertical manner compared to the horizontal manner we are accustomed to here on Earth.

The density of Titania is 1.662 g/cm3, which is less than half the density of Earth’s moon. Miranda Another moon of Uranus that is interesting is Miranda. It was discovered on February 16, 1948 by Gerard P. Kuiper. Its distance from Uranus is 129,900 km or 80,716 miles and takes 1.413 Earth days to make 1 complete orbit around the planet. Miranda’s average diameter is 471.6 km or 293 miles with a mass of 6.5941 x 1019 kg. Sounds boring so far, what’s so interesting about it? Well if you like the Grand Canyon, then you’ll definitely like Miranda. This moon’s fault canyons can be more than 10 times as deep as the Grand Canyon. Scientists are not sure why such a rigid surface exists on Miranda, where some believe it may be from other objects crashing into it which would raise the partially melted ice to the surface causing this rigid formation.

Building on this possible theory since about 42 years are in straight sunlight for each pole the Sun may play some role in helping the ice melt when foreign objects crash into it. Ariel What’s Uranus’s brightest moon? That would be Ariel, which was discovered on October 24, 1851 by William Lassell. Its distance from Uranus is 190,900 km or 118,620 miles and takes 2.52 Earth days to make 1 complete orbit around the planet. Ariel’s average diameter is 1,157.8 km or 719.4 miles with a mass of 1.2948 x 1021 kg. Its composition is believed to be about 50% ice and 50% rock. Ariel’s other notable feature is its long canyons which run across its surface. The reason for these unique canyons is unknown. Some scientists rule out it being from water because at these temperatures it is very difficult for water to form.

However one must also think that if a large asteroid came colliding with Ariel, enough heat could be produced from the collision which would temporarily melt the ice. Umbriel Ever wonder what a fluorescent cheerio would look like on a moon. Then look at Uranus’s moon Umbriel which has a bright ring spot on it. One of the theories behind this distinctive feature is it was impacted by some large object which caused the inner material (which is brighter than the surface) of the moon to surface. But that is still a mystery on why it has that bright ring. Umbriel was discovered in the year 1851 by William Lassell. Its distance from Uranus is 266,000 km or 165,285 miles and takes 4.144 Earth days to make 1 complete orbit around the planet. Umbriel’s average diameter is 1,169.4 km or 727 miles with a mass of 1.2214 x 1023 kg. List of Uranus Moons Astronomy for Kids - The Moons of Uranus Please click here for more information.

The Five Largest Moons of Uranus Image courtesy of: NASA-Voyager mission Currently, we know that Uranus has at least twenty-one moons. The above image is a "family portrait" of the five largest moons of the planet. From left to right, they are Miranda, Ariel, Umbriel, Titania and Oberon. The Voyager mission discovered ten more moons when it visited the planet in 1986 and since then, astronomers have discovered six more. Image courtesy of: NASA - Voyager mission Miranda Although it is the smallest of the five larger moons of Uranus, Miranda nonetheless has presented us with a number of puzzles. If you look closely at the picture at the right, you will notice that about half of the moon looks like a lot of the other moons in our solar system. It has lots of craters that tell us that it has been hit by many objects during its long life. The other half of the moon is covered by what appear to be giant cliffs, grooves, gullies and other features a lot like you might find in the American West, although much, much larger. What has caused all of these unusual features?

In all honesty, nobody really knows, and the only we will find out is to send another spacecraft to the distant planet for an extended visit. Image courtesy of: NASA The half of Miranda that is covered with canyons, valleys and giant ridges is the most interesting part of this tiny world. Among the fascinating features of this region is the giant cliff shown in the picture at right. Although the moon is a little under three hundred miles in diameter, the ridge shown in the picture is taller than Mount Everest here on Earth. How did such a small world become the home of such a large cliff? It is one of the many questions that remain unanswered. Image courtesy of: NASA - Voyager mission Ariel The second of the large Moons of Uranus is Ariel. Ariel, with a diameter of almost 720 miles, is much larger than Miranda and is made up mostly of rocky material and ice. The pictue at right shows an interesting world that one side has lots of craters much like our own Moon, but the other side is criss-crossed by what appear to be large grooves of some kind. What causes such unusual features?

One explanation may be that at some time in the distant past Ariel might have been much warmer than it is now. If this is the case, some of the ice in the moon may have melted and smoothed out the surface of the moon and then more recent geological activity may have formed the long, wide grooves we see in the picture. Once again, it's a question that only extended research will provide the answer to. Image courtesy of: NASA - Voyager mission Umbriel The third in the family of the five largest moons of Uranus is Umbriel. Although Umbriel is about the same size as Ariel, the family resemblance ends there. Where Ariel shows us a face that has lots of interesting and mysterious features, Umbriel is more like what most moons look like. It does have lots of impact craters, but other than that, it's a pretty cold, plain place. The only really interesting feature of this moon is the bright crater you can see at the top of the picture at the right. This crater is very large, almost seventy miles across, and is also very bright, compared to the surface of the rest of the moon. Does the interior of this moon contain material that is actually much lighter in color or was the crater just created recently?

Either of these would provide an explanation as to why the crater is so much brighter than the rest of the surface. Image courtesy of: NASA - Voyager mission Titania At a little over 980 miles in diameter, Titania is the largest moon of Uranus, as befits its name. Like the other moons of the planet that we have seen, Titania is made up of rocks and ice. Another thing that Titania has in common with its family members is the fact that part of its surface is heavily cratered, and part of it has lots of ridges, gullies and other features that look like erosion features that we see here on Earth and on Mars. What special set of circumstances have occurred during the planet's history could have caused this? Hopefully, some future mission to the planet will provide answers to the many questions we have. Image courtesy of: NASA - Voyager mission Oberon The last of the largest moons of Uranus is Oberon. At a little over 945 miles in diameter, this moon is just a little smaller than Titania. What Oberon doesn't have that its other family members have is a region that is covered with ridges and gullies.

This moon is almost entirely covered by impact craters, much like most of the other moons in the solar system. If you look closely, though, at the bottom left hand side of the image you can just barely make out what appears to be a "mountain" rising from the surface of the moon. This mountain is over three miles high and is the most interesting feature on the surface of this moon. Space Today Online - Solar System - Planet Uranus - Moons Margaret 2003 Click to enlarge Voyager 2 photos in 1986 of the Uranus moons Umbriel (left) and Ariel (right). The planet Uranus has at least 27 moons that we know of. Before the planet was visited by the spacecraft Voyager 2 on January 24, 1986, astronomers knew of only five. Voyager 2 discovered ten small moons. Today, astronomers suggest there may be more tiny satellites among the planet's rings. The moons of Uranus are eye-openers. They have statuesque mountains towering more than ten miles high. Incredibly deep valleys. Vast plains, some with a mysterious dark surface.

Moon diameters range from a bit fatter than 25 miles up to about 1,100 miles.They circle Uranus in orbits ranging from every eight hours to every 14 days. Some of the moons are very tiny. Click to enlarge Voyager 2 image of the planet Uranus Voyager 2 found moons. The interplanetary probe Voyager 2 flew within 50,600 miles of Uranus' cloud tops on January 24, 1986, discovering a magnetic field and much ultraviolet light, known as dayglow. Voyager 2 found 10 previously-unknown moons, the largest only 90 miles in diameter, bringing the total to 15. Astronomers previously had seen five large ice-and-rock moons. The innermost, Miranda, was found by Voyager to be one of the strangest bodies in the Solar System, with fault canyons up to 12 miles deep, terraced layers and mixed young and old surfaces. Titania was marked by huge faults and deep canyons. Ariel had the brightest and youngest surface of Uranian moons, with many deep valleys and broad ice flows.

Dark-surfaced Umbriel and Oberon looked older. The moons Umbriel and Ariel each are about 75O miles in diameter. In NASA's 1986 pictures at right, Voyager 2 was about 346,000 miles from Umbriel. The Ariel picture is a mosaic of four images collected when Voyager 2 was about 8O,OOO miles from the moon Voyager found nine rings around Uranus, but they were quite different from Jupiter and Saturn rings. Uranus' rings may be young remnants of a shattered moon. NASA image of the planet Uranus Moons discovered in the 1990s. Until 1997, Uranus was the only one of the giant gas planets in our Solar System without any known tiny moonlets. In 1997, J.J. Kavelaars of the Dominion Astrophysical Observatory in British Columbia, and a team of astronomers found the 16th and 17th satellites of Uranus. Those moons are named Caliban and Sycorax.

In 1999, Erich Karkoschka of the University of Arizona spotted an 18th Uranian satellite in a Voyager 2 photograph snapped in 1986. In 1999, Kavelaars and a team of astronomers discovered the 19th and 20th moonlets orbiting Uranus. Designated 1999 U1 and 1999 U2, they are dark rocks less than 12 miles in diameter. All newly-discovered Uranian moons are, or will be, named after Shakespearean characters. New moonlet, in white circle, orbiting Uranus, bottom left Source: International Astronomical Union 22 moons in 2002. Uranus has more than 20 satellites. The total number known in 2002 was 22, although astronomers were uncertain because newly-discovered moonlets were not always confirmed immediately by other astronomers. Uranus was known to have ten so-called "regular" natural satellites that follow orderly paths around the planet all in about the same plane.

Also known were six so-called "irregular" moons, including a newly-discovered tiny moonlet known as S/2001. The irregulars were seen to be traveling in odd orbits around Uranus and may be remnants of a massive ancient collision between a comet and some other large object that had been orbiting Uranus. S/2001 was the smallest Uranian satellite found so far, estimated to be 9 to 12 miles in diameter. It was discovered in 2001 by Matthew Holman of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, J.J. Kavelaars of the Dominion Astrophysical Observatory in British Columbia, and Dan Milisavljevic of McMaster University in Ontario. The first sighting was made with the Canada-France-Hawaii Telescope and the Cerro-Tololo Inter-American Observatory in Chile. » October 24, 2001, was the 150th anniversary of William Lassell's 1851 discovery of Uranus' Click to enlarge the NASA diagram depicting rings (red lines) and moons (blue dashed lines) orbiting Uranus. The new rings are labeled R1 and U2.

The newly-discovered moons are Mab and Cupid. Credit: NASA, ESA, and M. Showalter of the SETI Institute. Hubble sees moons and rings in 2005. The distant planet continues to surprise astronomers. Using NASA's Hubble Space Telescope in 2005, they uncovered a pair of giant rings girdling the planet. The largest ring is twice the diameter of the planet's previously known ring system. The first Uranus ring discoveries were made in the 1970s. The astronomers looking at Uranus with the Hubble Space Telescope saw two small moons – Mab and Cupid – discovered in 2003. One of the moons shares an orbit with the outermost newly-found ring. That moon probably is the source of the fresh dust that replenishes the ring with matter knocked off the moon by meteoroid impacts. Without the ongoing replenishment, the ring would disappear as its dust spiraled slowly down onto Uranus. The Hubble discoveries suggest Uranus has a young, dynamic system of rings and moons. Unlike the famous rings around Saturn, the rings around Uranus are dim and dark because they are mostly dust rather than ice.

Due to the extreme tilt of Uranus's axis, the rings appear to be nearly perpendicular relative to rings around other gas giant planets like Saturn. Hubble Space Telescope image of Uranus ring More moons will be found. British astronomers say they believe Uranus may have many more natural satellites than have been seen. For instance, the moons Cordelia and Ophelia are shepherds, keeping the eleven large rings around Uranus from spreading into space. But, astronomers at London University say the two shepherd moons are not enough to explain the thin sharp edges on the rings. They figure there could be as many as 25 more small moonlets out there with their gravity pulling the rings into shape. Such small shepherd moons might range from one to 12 miles in diameter. Ring gaps in some Voyager 2 photos, combined with a mysterious wave in one ring, may indicate two of the unseen moons could be 11 miles in diameter. They could be orbiting at 28,200 and 28,800 miles from the center of the planet. Who names moons?

The International Astronomical Union (IAU), a worldwide association of 6,000 professional astronomers headquartered in Paris, has been responsible for naming planetary bodies since IAU was formed in 1919. Harold Masursky, a planetary geologist with the U.S. Geological Survey in Flagstaff, Arizona, heads the IAU planetary system nomenclature working group. Astronomers say, even though the Uranus moons were discovered by the United States, the natural satellites are international. Naming features or moons is not the property of one country. Going along with tradition receives international acceptance. The IAU did name craters on Earth's Moon for the seven crew members -- Francis Scobee, Michael J. Smith, Judith Resnik, Ronald McNair, Ellison Onizuka, Gregory Jarvis and teacher-astronaut Sharon Christa McAuliffe -- killed in the 1986 shuttle Challenger launch explosion. The craters, 20 to 60 miles wide, are within a vast crater named Apollo on the far side of the Moon. Also, seven asteroids were named in 1986 by the IAU for the Challenger astronauts, two months after the shuttle exploded.

The IAU previously had named craters on Earth's Moon for nine American astronauts and nine Soviet cosmonauts -- most living, some dead -- including Roger Chaffee, Gus Grissom and Ed White, killed when a launch pad fire swept the Apollo 1 spacecraft in 1967. Shakespeare. Nine of the new Uranus moons found by Voyager in 1986 were named for Shakespearean characters: Bianca, Cordelia, Cressida, Desdemona, Juliet, Ophelia, Portia, Puck and Rosalind. The tenth was named for Belinda whose lock of hair was stolen in The Rape of the Lock. Three of five previously-known Uranus moons – Oberon, Titania and Miranda – have Shakespearean names. Umbriel is from Pope's poem. Ariel is a name in both The Rape of the Lock and Shakespeare's The Tempest. Moons of other planets mostly have been named for characters from Roman mythology. Use of literary names for moons of Uranus was started by English brewer and astronomer, William Lassell. He discovered Ariel, Oberon, Titania and Umbriel in 1851.

Voyager discovered the moons shortly before the January 28, 1986, shuttle Challenger disaster. Two U.S. congressmen had proposed naming the 10 moons for dead Challenger and Apollo 1 crew members. They prompted thousands of children, citizens and officials to write letters and sign petitions favoring naming moons for astronauts. Lots and lots of moons. There are at least 156 moon in the Solar System. With a total of 63, Jupiter currently has the most known natural satellites of any planet in the Solar System. Saturn is second with 47. Uranus has 27. Neptune has 13. Pluto has 3. Mars has 2. Earth has 1. The moon totals for Jupiter, Saturn, Uranus, Neptune and Pluto can be expected to increase as more powerful telescopes become available in the future. More about the Solar System . . .

Star: Uranus' Moons Uranus' Moons A schematic (to-scale) of the ring & moon system of Uranus Uranus has 27 identified moons to date, three of which (Ariel, Umbriel & Belinda) are named from a poem by Alexander Pope, while the remainder are named after characters from Shakespeare. The table to the right lists the moons in order from Cordelia, closest to Uranus, outwards with their diameters in kilometers. The smaller moons are, as usual, far from spherical, but the measurement indicates a nominal diameter. Where available, I have linked to photographs of the moon. The thirteen moons out to the newly-discovered (in 2003) Mab are considered "inner moons". They are all orbiting within the ring system, and some, Cordelia & Ophelia, for example, act as "shepherd moons" keeping the rings in place. The orbits of these moons are fairly chaotic and, over millions of years, the orbits cross each other, leading to the risk of collisions. This may well be how the rings originated.

These moons formed from an accretion disk that was either present when Uranus formed, or resulted from the possible collision event Uranus suffered which tilted it so far on its axis. The next five moons are the largest. Miranda is made primarily of ice, probably including ammonia and carbon dioxide. The other four are roughly half ice and half rock, with rocky cores covered with an ice mantle. While all five are cratered, all but Umbriel show signs of geological activity that has resurfaced the planet in the past. The nine outer moons are all small and irregular, and are almost certainly captured objects. Unlike all the other moons, the outer moons, except Margaret, have retrograde orbits. Margaret's orbit, while prograde, has a large eccentricity. The four largest moons make up 99.2% of the mass of Uranus' moons system. Miranda is a further 0.7% while the remaining 22 moons make up barely 0.1%. Oberon, the furthest of the large moons from Uranus, orbits about 583,500 km (365,000 miles) from Uranus.

There is then a huge gap until we reach Francisco which orbits some 4,276,000 km (2,672,000 miles) from Uranus, with Ferdinand out at 20,900,000 plus km (13,060,000 miles). This montage shows Uranus and its five major moons. The images are from the Voyager 2 spacecraft. As shown here, the moons, from largest to smallest, are Ariel, Miranda, Titania, Oberon and Umbriel. Links Wikipedia has an excellent table with information about all of Uranus' Moons . NASA also has more information on Uranus' Moons . Uranus' Moon Umbriel - Universe Today Universe Today by Matt Williams The 19th century was an auspicious time for astronomers and planet hunters. In addition to the discovery of the Asteroid Belt that rests between Mars and Jupiter – as well as the many minor planets within – the outer solar planet of Uranus and its series of moons were also observed for the very first time. Of these, Umbriel was certainly one of the most interesting finds.

Aside from being Uranus’ third largest moon, it is also its darkest – a trait which contributed greatly to the selection of its name. And to this day, this large satellite of Uranus is shrouded in mystery… Discovery: Umbriel, along with its fellow moon Ariel , was discovered by English astronomer William Lassell on October 24th, 1851. Fellow English astronomer William Herschel, who had discovered Uranus’ moons of Titania and Oberon at the end of the 18th century, also claimed to have observed four additional moons around Uranus. However, his observations were not confirmed, leaving the confirmed discoveries of Ariel and Umbriel to Lassell, roughly half a century later. Naming: Much like all of Uranus’ 27 moons , Umbriel was named after a character from Alexander Pope’s The Rape of the Lock, as well as plays by William Shakespeare. These names were suggested by John Herschel, the son of William Herschel, when he announced the discoveries of Titania and Oberon. Size comparison of Earth, the Moon, and Umbriel.

Credit: Tom Reding/Public Domain In keeping with the moon’s dark appearance, the name Umbriel – which was the name of the ‘dusky melancholy sprite’ in the The Rape of the Lock and is derived from the Latin Umbra (which means “shadow”) – seemed most appropriate for this satellite. Size, Mass and Orbit: Ariel and Umbriel are nearly the same size, with diameters of 1,158 kilometers and 1,170 kilometers respectively. Based on spectrograph analyses and estimates of the moon’s mass and density, astronomers believe that the majority of the planet consists of water ice, with a dense non-ice component constituting around 40% of its mass. This could mean that Umbriel consists of an icy outer shell that surrounds a rocky core, or one made out of carbonaceous materials. It also means that though Umbriel is the third largest moon of Uranus, it is only the fourth largest in terms of mass. Furthermore, its dark appearance is believed to be the result of the interactions of surface water ice with energetic particles from Uranus’ magnetosphere.

These energetic particles would cause methane deposits (trapped in the ice as clathrate hydrate) to decompose and other organic molecules to darken, leaving behind a dark, carbon-rich residue. The satellite’s dark color is also due to its very low bond albedo – which is basically the amount of electromagnetic radiation (i.e. light) that gets reflected back from the surface. So far, spectrographic analyses have only confirmed the existence of water and carbon dioxide. So the existence of organic particles or methane deposits in the ice remains theoretical. However, their presence would explain the prevalence of CO² and why it is concentrated mainly on the trailing hemisphere. Umbriel’s orbital period – i.e. the time it takes the moon to orbit Uranus – is approximately 4.1 days, which is coincident with its rotational period. This means that the moon is a synchronous and tidally-locked satellite, with one face always pointing towards Uranus. The satellite is at an average distance of 266,000 kilometers from its planet, which makes it the third farthest from Uranus, behind Miranda and Ariel.

Voyager 2: So far, the only close-up images of Umbriel have been provided by the Voyager 2 probe, which photographed the moon during its flyby of Uranus in January of 1986. During this flyby, the closest distance between Voyager 2 and Umbriel was 325,000 km (202,000 mi). The images cover about 40% of the surface, but only 20% was photographed with the quality required for geological mapping. At the time of the flyby, the southern hemisphere of Umbriel was pointed towards the Sun – so the northern, darkened hemisphere could not be studied. At present, no future missions are planned to study the moon in greater detail. US Geological Survey map of Umbriel, showing its cratered surface and polygons. Credit: ISGS Interesting Facts: The surface of Umbriel has far more and larger craters than do Ariel and Titania, ranging in diameter from a few kilometers to several hundred. The largest known crater on the surface is Wokolo, which is 210 km in diameter.

Wunda , a crater with a diameter of about 131 kilometers, is the most noticeable surface feature, due to the ring of bright material on its floor (which scientists think are from the impact). Other craters include Fin, Peri, and Zlyden which, like all of Umbriel’s surface features, are named after dark sprites from different cultures’ mythology. The only satellite of Uranus to have more craters is Oberon, and the planet is believed to be geologically stable. It is further believes that surface has probably been stable since the Late Heavy Bombardment . The only signs of ancient internal activity are canyons and dark polygons – dark patches with complex shapes measuring from tens to hundreds of kilometers across. The polygons were identified from precise photometry of Voyager 2′s images and are distributed more or less uniformly on the surface of Umbriel, trending northeast – southwest. Because Uranus orbits the Sun almost on its side, it is subject to an extreme seasonal cycle. Both northern and southern poles spend 42 years in complete darkness, and another 42 years in continuous sunlight, with the Sun rising close to the zenith over one of the poles at each solstice.

The southern hemisphere of Umbriel displays heavy cratering in this Voyager 2 image, taken Jan. 24, 1986. The large impact crater of Wunda is visible at the top. Credit: NASA/JPL Because they are in the planet’s equatorial plane, Uranus’ satellites also experience these changes. This means that Umbriel’s north and south poles spend 42 years in light and then 42 years in darkness before repeating the cycle. In fact, the Voyager 2 flyby coincided with the southern hemisphere’s 1986 summer solstice, when nearly the entire northern hemisphere was in darkness. Interesting little moon isn’t it? Even though no missions are currently planned to observe it in the coming years, one can only hope that future satellites happen to sneak a peek at it on their way to some other destination in the outer Solar System. Universe Today has many interesting articles on the moons of Uranus , like how many moons does Uranus have? You should also check out NASA’s page on Umbriel and Uranus’ moon Umbriel at Nine Planets. Astronomy Cast has an episode on Uranus that you should check out.

Sources: Solar System Moons - An Introduction to AstronomyAn Introduction to Astronomy Solar System Moons 1. Which of the following Solar System moons are associated with the planet Mercury? A. Mercury has no moons. B. Phobos and Deimos C. Io, Europa, Ganymede, Callisto D. Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus E. Miranda, Ariel, Umbriel, Titania, Oberon F. Proteus, Triton, Nereid 2. Which of the following Solar System moons are associated with the planet Venus? A. Venus has no moons. B. Phobos and Deimos C. Io, Europa, Ganymede, Callisto D. Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus E. Miranda, Ariel, Umbriel, Titania, Oberon F. Proteus, Triton, Nereid 3. Which of the following Solar System moons are associated with the planet Mars? A. Mars has no moons. B. Phobos and Deimos C.

Io, Europa, Ganymede, Callisto D. Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus E. Miranda, Ariel, Umbriel, Titania, Oberon F. Proteus, Triton, Nereid Phobos and Deimos. The origin of these relatively small moons remains uncertain but asteroid capture is a long-favored theory. Phobos is projected to either impact the Martian surface, or more probably, break up into a planetary ring which will continue to spiral slowly into Mars in an estimated 7.6 to 11 million years. 4. Which of the following Solar System moons are associated with the planet Jupiter? A. Jupiter has no moons. B. Phobos and Deimos C. Io, Europa, Ganymede, Callisto D. Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus E. Miranda, Ariel, Umbriel, Titania, Oberon F. Proteus, Triton, Nereid Jupiter has 66 moons but Io, Europa, Ganymede and Callisto are the four largest.

All four have radii larger than any of the dwarf planets. These are also known as Galilean Moons. 5. Which of the following Solar System moons are associated with the planet Saturn? A. Saturn has no moons. B. Phobos and Deimos C. Io, Europa, Ganymede, Callisto D. Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus E. Miranda, Ariel, Umbriel, Titania, Oberon F. Proteus, Triton, Nereid Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus. Saturn has at least 62 moons, 53 of which have formal names. Titan, the largest with a mean diameter of 5,152 km (3,200 miles), makes up 90% of the mass in orbit around Saturn, including the rings. Rhea, the 2nd largest, has a mean radius about 30% that of Titan. Many of Saturn’s other moons are less than 50 km (31 miles) in diameter. 6.

Which of the following Solar System moons are associated with the planet Uranus? A. Uranus has no moons. B. Phobos and Deimos C. Io, Europa, Ganymede, Callisto D. Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus E. Miranda, Ariel, Umbriel, Titania, Oberon F. Proteus, Triton, Nereid Miranda, Ariel, Umbriel, Titania, Oberon. Uranus has 27 known moons but Miranda, Ariel, Umbriel, Titania, and Oberon compose the five main natural satellites. The Uranian satellite system is the least massive among the gas giants. The largest moon, Titania, has a diameter of only 1578 km ( 980 miles). 7. Which of the following Solar System moons are associated with the planet Neptune? A. Neptune has no moons. B. Phobos and Deimos C. Io, Europa, Ganymede, Callisto D. Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus E.

Miranda, Ariel, Umbriel, Titania, Oberon F. Proteus, Triton, Nereid Proteus, Triton, Nereid. Neptune has 13 known moons. Triton, with a diameter of 2700 km (1,680 miles), is by far the largest, comprising more than 99.5 percent of the mass in orbit around Neptune. Solar System Moons – Descriptions 8. What is the name of this solar system object? Full Moon as seen from the Earth’s Northern Hemisphere. A. The Moon B. Mercury The Moon. The Moon is the only natural satellite of the Earth, and is the fifth largest of the Solar System moons. It is characterized by its large, dark volcanic maria which form part of the “Man in the Moon.” The Moon is, under the Outer Space Treaty, free to all governments and privately funded organizations to explore for peaceful purposes.

The Moon orbits at an elliptical semi-major axis distance of 384,399 km (238,854 miles) around the Earth and its mean diameter is 3,475 km (2,160 miles), about ¼ the size of the Earth. 9. What is the name of this solar system object? A. Phobos B. Deimos Mars larger and closer Moon, Phobos. Phobos. Mars moon, Phobos, is the larger and closer of the two small natural satellites orbiting Mars. Phobos is projected to either impact the Martian surface, or more probably break up into a planetary ring which will continue to spiral slowly into Mars in an estimated 7.6 to 11 million years. Phobos orbits at an elliptical semi-major axis distance of 9,377 km (5,827 miles) around Mars and its mean diameter is 22.2 km (13.8 miles). 10. What is the name of this solar system object? Mars smaller and outer Moon, Deimos. A. Phobos B. Deimos Deimos.

Mars moon, Deimos, is the smaller and outer of the two small natural satellites orbiting Mars. Both Phobos and Deimos were discovered by Asaph Hall, Sr. at the United States Naval Observatory in August 1877 while deliberately searching for Martian moons – Deimos on August 12th and Phobos on August 18th. Deimos orbits at an elliptical semi-major axis distance of 23,460 km (14,580 miles) around Mars and its mean diameter is 12.4 km (7.8 miles). 11. What is the name of this solar system object? Jupiter’s innermost Galilean Moon, IO. A. Io C. Ganymede D. Callisto Io. Jupiter’s moon, Io, is the innermost of the four Galilean moons orbiting the planet Jupiter. With over 400 active volcanos, Io is the most geologically active object in the solar system. This activity is a result of tidal heating in its interior as it pulled between Jupiter and the other Galilean satellites, Europa, Ganymede, and Callisto.

Most of Io’s surface is covered with sulfur and sulfur dioxide frost. Io orbits at a radius of 422,000 km (262,000 miles) from the center of Jupiter and 350,000 km (217,000 miles) above its cloud tops. Io’s mean diameter is 3,640 km (2,260 miles). 12. What is the name of this solar system object? Jupiter Moon, Europa. C. Ganymede D. Callisto Europa. Jupiter moon, Europa, is the smallest of the four Galilean moons of Jupiter, being slightly smaller than Earth’s Moon. Europa has a tenuous atmosphere composed mostly of molecular oxygen (O2) formed through the process of radiolysis rather than biologically as is the case for the Earth’s atmospheric oxygen. Europa is one of the top Solar System locations for the possibility of hosting extraterrestrial life, which could exist in its underice ocean.

Europa orbits Jupiter at an orbital radius of 670,900 km (417,000 miles) from the center of Jupiter and its mean diameter is 3,100 km (1,950 miles). 13. What is the name of this solar system object? Jupiter Moon, Ganymede. Enceladus. Saturn moon, Enceladus, is one of only three outer Solar System moons (along with Jupiter’s moon Io and Neptune’s moon Triton) where active eruptions have been observed. Analysis of the outgassing suggests that they originate from a body of subsurface liquid water. This observation, along with the unique chemistry found in the plume, has fueled speculation that Enceladus may be important in the study of astrobiology.

NASA scientists have reported (In May 2011) that Enceladus “is emerging as the most habitable spot beyond Earth in the Solar System for life as we know it.” Enceladus orbits at an elliptical semi-major axis distance of 238,000 km (148,000 miles) around Saturn and its mean diameter is 500 km ( 310 miles). 17. What is the name of this solar system object? Saturn Moon, Tethys. D. Titania E. Oberon Oberon. Uranus moon, Oberon, is the outermost major moon of the planet, Uranus. Oberon is the second largest and second most massive of the Uranian moons. Like Titania, the surface of Oberon is relatively dark and slightly red in color. Oberon orbits at an elliptical semi-major axis distance of 583,500 km (362,600 miles) around Uranus and its mean diameter is 1,520 km ( 945 miles). 27. What is the name of this solar system object? Neptune Moon, Proteus.

B. Triton C. Nereid Proteus. Neptune moon, Proteus, is the second largest moon of Neptune behind the mysterious Triton. Proteus was discovered only in 1989 by the Voyager 2 spacecraft. This is unusual since Neptune’s smaller moon, Nereid, was discovered 33 years earlier from Earth. Proteus orbits at an elliptical semi-major axis distance of 117,650 km (73,120 miles) around Neptune and its mean diameter is 210 km (131 miles). 28. What is the name of this solar system object? Neptune Moon, Triton. B. Triton C. Nereid Triton. Neptune’s largest moon, Triton, is the only large moon in the Solar System with a retrograde orbit, which is an orbit in the opposite direction to its planet’s rotation. Because of its retrograde orbit and composition similar to Pluto’s, Triton is thought to have been captured from the Kuiper belt.

Triton orbits at an elliptical semi-major axis distance of 355.000 km (220,000 miles) around Neptune and its mean diameter is 1350 km (840 miles). 29. What is the name of this solar system object? Neptune Moon, Nereid. B. Triton C. Nereid Nereid. Neptune moon, Nereid, is the third-largest moon of Neptune and has a highly eccentric orbit. It was discovered in 1949 on photographic plates taken with the 82-inch telescope at the McDonald Observatory at the University of Texas at Austin. Nereid orbits at an elliptical semi-major axis distance of about 5,510,000 km (3,425,000 mi) around Neptune, but its high eccentricity of 0.7507 takes it as close as 1,372,000 km (853,000 mi) and as far as 9,655,000 km (5,999,000 mi) from the planet.

Its mean diameter is roughly 170 km (105 miles). 30. Which of the following are the names of the Solar System moons of the dwarf planet, Pluto? A. Charon, Nix, Hydra, S/2011, S/2012 B. Dysnomia C. Hi’iaka, Namaka A. Charon, Nix, Hydra, S/2011, S/2012. Charon and Pluto revolve about each other every 6 days. The two objects are gravitationally locked, so each keeps the same face towards the other. The average distance between Charon and Pluto is 19,570 km (12,160 miles). Charon’s mean diameter is 1.207 km (750 miles), just over half the diameter of Pluto. Nix and Hydra orbit Pluto at approximately two and three times the distance of Charon: Nix at 48,700 km (30,267 miles) and Hydra at 64,800 km (40,273 miles) from the barycenter of the system.

They have nearly circular prograde orbits in the same orbital plane as Charon. Observations of Nix and Hydra to determine individual characteristics are ongoing. 31. Which of the following are the names of the Solar System moons of the dwarf planet, Eris? A. Charon, Nix, Hydra, S/2011, S/2012 B. Dysnomia C. Hi’iaka, Namaka B. Dysnomia. Dysnomia is the only known moon of the dwarf planet, Eris. 32. Which of the following are the names of the Solar System moons of the dwarf planet, Haumea? A. Charon, Nix, Hydra, S/2011, S/2012 B. Dysnomia C. Hi’iaka, Namaka C. Hi’iaka, Namaka. Hi’iaka, the larger, outermost moon, has large amounts of pure water ice on its surface and orbits Haumea in a nearly circular path every 49 days. Namaka, about one tenth the mass of Hi’iaka, orbits Haumea in 18 days in a highly elliptical orbit.

REFERENCES: Most of the content in this section regarding the Solar System moons consists of information from this NASA reference and from this Wikipedia.org reference , and their associated pages.

Question: Miranda, Ariel and Umbriel are all moons of which planet in our solar system?
Answer: Uranus