The Major Moons of Uranus
Oberon, Titania, Umbriel, Ariel, and Miranda
Mighty blue Uranus dares to be different, for unlike his planetary siblings, he has chosen his companions from the literary works of William Shakespears and Alexander Pope.
Here we will seek out the wonders of the five largest moons of Uranus.
Thanks to NASA and JPL for the images!
Uranus and Six Moons
Six of the moons of Uranus in order from left to right are: Puck, Miranda, Ariel, Umbriel, Titania and Oberon. This is a proportionate composite of images by Voyager 2.
Oberon is the second largest moon of Uranus and the outermost of the larger moons. It was discovered on January 11, 1787 by William Herschel, and the only close pictures are those from Voyager 2.
Since there is little information about Oberon, scientists believe it is made up of 50% water ice, 30% rock, with the remaining 20% possibly methane, nitrogen, and carbon compounds.
It has an old, heavily cratered and icy surface which shows little evidence of internal activity other than some unknown dark material that apparently covers the floors of many craters. However, some large faults can be seen across the southern hemisphere, which indicates some internal activity early in its life.
So far, scientists have recognised a few types of geological features on Oberon: craters, chasmata, and mountains. In fact one such mountain rises about 6 kilometers (3.7 miles) above the Oberonian surface.
The Oberon Terrain
Oberon's cratered terrain is ancient, but there are a few signs that hint at geological activity in it's recent past. The floors of the craters are covered in some unknown dark material, but some scientists believe it may be dirty water. These craters emit bright ejecta rays like those seen on Jupiter's moon, Callisto.
One feature easily seen in the pictures taken by Voyager 2 is the huge mountain. This mountain is speculated at being at least 4 miles high, but the base of this mountain is hidden, so this is just conjecture.
Oberon has no discernable atmosphere and no magnetic field.
Titania is the largest moon of Uranus and is about 947 miles(1580 km) in diameter. It was discovered on January 11,1787, by William Herschel.
Titania has either a very thin, or no atmosphere.
Not much is known about Titania, but scientists theorize that the moon is made up of 50% water ice, 30% silicate rock, and 20% methane-related compounds. Titania takes only 9 Earth days to complete one orbit.
The surface of Titania is less cratered than some of the other moons on our solar-system, and therefore may be quite young.
The moon Titania has several valleys called rifts on its surface. There is one in particular that is quite impressive. An extremely large canyon on Titania, called Messina Chasmata, is a major feature that dwarfs our own Grand Canyon and can be seen in the image to the left as white grooves. It is large enough to be in the same class as the Ithaca Chasma on Saturn's moon Tethys. This canyon is believed to be about 1,000 miles (1600km) long. Scientists believe it may have been formed when Titania was still hot enough to have liquid water, and when the moon cooled, the ice expanded, cracking the surface.
Umbriel, the darkest moon of Uranus, was discovered by William Lassell on October 24, 1851. Umbriel is 727 miles (1170 km) in diameter and has no known atmosphere and no magnetic field.
Umbriel is believed to be the least geologically active of all Uranus's moons, and has an ancient surface with large craters. Umbriel is made of mostly water ice and rock with frozen methane contributing to it's dark color, however, the reason it is so dark compared to the other moons of Uranus is unknown.
One striking feature on Umbriel is the Fluorescent Cheerio, later formally named Wunda. Seen at the top of Umbriel in the image here, it is not entirely known what this really is, although experts believe it is the floor of a large crater. What is so fascinating about the Fluorescent Cheerio is how bright it is compared to the rest of Umbriel, especially since heavily cratered Umbriel is so dark.
Ariel was discovered on October 24, 1851, by William Lassell. It was discovered at the same time as Umbriel.
Ariel is made of about 70% ice and 30% silicate rock. Ariel seems to have regions of frost coating parts of the surface, especially in the ejecta areas around the younger impact craters.
Ariel is thought to be like Saturn's Dione because they are similar in size, diameter and mass, with both seeming to have had past geological activity.
The Face of Ariel
Ariel has an extensive cratered area near the south pole. These are small, young craters, with the largest called Yangoor.
Ariel also has a network of faults and canyons running through the cratered plains region. Smooth looking material has also been seen on Ariel, running along the same paths of Ariel's valleys and canyons, and are believed to be ice on the floors of these structures.
Miranda was discovered on February 16, 1948, by Gerard Kuiper. It is 293 miles (472 km)in diameter, and the smallest and innermost of Uranus' five major moons.
Miranda is the most geologically active of Uranus' moons and one of the most unusual looking moons in our solar system.
It's a Strange, Strange Moon
Miranda's is thought to be made up of mostly water ice, containing silicate rock and organic compounds in its interior.
The surface of Miranda shows so much unusual terrain, that it must have had an amazing amount of geological activity in the past. Miranda has huge canyons, grooved structures, steep cliffs, odd rifts, and smooth plains.
There are several theories as to why Miranda looks so fractured. One theory, which is now considered most unlikely, is that Miranda was struck by a massive impact which shattered the moon, but the reassembled by Miranda's gravitational pull. the more popular theory is that the interior of Miranda sent melted ice to the surface which resulted in the surface features. These are only theories, and the real reason is unknown.
One of the most striking features on Miranda is the V-shaped figure called the Chevron. Miranda has so many extreme features, from exceedingly high mountains, to layered ridges, to deep canyons, that it is difficult to focus on just one outstanding structure.
Pick your Favorite Moon of Uranus
The Favorite is...
A bit on Uranus and some of its moons - Narrated by Patrick Stewart
A good video, although it does end rather abruptly and leaves you wanting more.