Trans-Jovian Moons in Fact and Fiction


It’s been a while since I’ve done one of these posts about extraterrestrial worlds in fact and (mostly) fiction. There’ve been (or will be) posts about Callisto, Ceres, Europa, Ganymede, Io, Mars, Pluto, Titan, VenusTrans-Neptunian dwarf planets, and Asteroids. The primary reason that there haven’t been more is because the more obscure the solar object, the less likely it is to have been a setting for a Science-Fiction work (and thus the less relevance to Amoeba). A secondary reason is that these posts are far less popular than my Los Angeles neighborhood, LA County community, or Orange County community posts — but aren’t moons and planets sort of the neighborhoods of our Solar System? So here I am with a round-up of several moons, the Trans-Jovian ones that appear in computer or video games, movies, TV shows and old time radio.


Moons of the Solar System, with Earth for Scale

There are currently 163 known Trans-Jovian moons. If the definition is broadened to include Trans-Neptunian objects, Trojan Moons, and Asteroids, then there are more than 336. Not surprisingly, most of them have not been the subject of any sci-fi fantasies.


Gas Giants

I’ve long been fascinated by the satellites of the gas giants. Whereas the planets they orbit seem unlikely to be colonized, the moons seem to be much more hospitable and tantalizing. Eight of them are larger than Pluto, which was formerly categorized as a planet. Imagine looking up to a sky dominated by a massive planet. It’s almost enough to give me a panic attack.

Composite panorama of Titan
Sunset on Titan as (panoramic composite created by Christian Waldvogel)

Today is the 357th anniversary of the discovery of the first Trans-Jovian moon (Titan) by Christiaan Huygens (25 March, 1655).Anyway, since Titan has already been the subject of a blog entry, here are the rest of the Trans-Jovian moons!



Saturn high resolution

Saturn is the second largest planet in the solar system, with a radius that’s approximately nine times that of Earth‘s. It is believed to have a rocky core underneath layers of liquid and gas which makes it pretty inhospitable. However, it has 62 known moons. Along with Ganymede (a satellite of Jupiter), Saturn’s moon of Titan is larger than Mercury, the smallest planet in the solar system, and is the only known satellite with a dense atmosphere and stable bodies of surface liquid.

Saturn’s other moons have less often captured the imagination of sci-fi creators (not counting literature, only because Amoeba‘s more of a music, movies and games store although there are some books!) but here’s what I’ve got:



Enceladus is the sixth largest moon of Saturn. The world is believed to have liquid water under its icy surface that is ejected into space by cryovolcanoes. Enceladus is one of only three outer Solar System bodies where active eruptions have been observed (the other two are Io, with its sulfur volcanoes, and Triton, with its nitrogen geysers. Some of the expelled water ends up in Saturn’s rings whilst some falls back to the moon’s surface as snow. Snow world!

Enceladus was a setting in the Buck Rogers radio episode, “Killer Kane and Ardala on Saturn’s moon.” It was the site of a battle in the Terran-Neosapien War in the cartoon Exosquad. On Life After People: The Seriesthe Cassini spacecraft crashes on Enceladus and the bacteria it carries evolve into new life forms. In the Futurama episode “Cold Warriors,” Enceladus is revealed to be Saturn’s main “dump moon.” And finally, on an episode of 宇宙戦艦ヤマト2199 (Space Battleship Yamato 2199), the crew of the Yamato briefly stops there and has an adventure.


Hyperion moon

Hyperion is the largest irregularly-shaped moon of Saturn, in fact, it was the first non-round moon to be discovered (in 1848 by by William Cranch BondGeorge Phillips Bond and William Lassell). Its orbit is fairly eccentric and its appearance is often compared to that of a sponge. It is believed to be composed mostly of water ice.

Level 16 of the Parallax Software game Descent takes place on there.


Mimas moon

Mimas is the smallest astronomical body that is known to be rounded in shape because of self-gravitation. Its surface area is close to that of the Earth country known as Spain. Mimas’s most distinctive feature is a giant impact crater 130 kilometres across (named Herschel after the moon’s discoverer, William Hershel) that gives it the appearance of the Death Star.

Mimas was a recurring location in Red Dwarf and produces the local delicacy, “Mimean Bladderfish.” In the Star Trek: The Next Generation episode “The First Duty,” Mimas is where Wesley Crusher and other Starfleet cadets transport after participating in the banned Kolvoord Starburst.


Tethys moon

Tethys is mostly made of water ice — less than 6% of the planet consists of rocky material! It is heavily cratered but its dominant characteristic is the more than 2000 km long (and 100 km wid) Ithaca Chasma. The huge graben is possibly related to the moon’s largest impact crater, the 400 km across Odysseus crater.

Tethys is the setting of the bizarre, Alien cash-in Stanley Donen Saturn 3 (directed by Stanley Donen from a screeplay by Martin Amis). On Exosquad, Tethys was at one point the primary base of the Pirate Clans. Level 17 of Descent takes place there too.



Uranus high resolution planet

The less-preferred, not-very-Latin-sounding but common pronunciation of Uranus (as “yer anus”) makes it a favorite planet amongst the elementary school set. It’s the third largest planet in the solar system and the largest of the two so-called ice giants. Its axis of rotation is tilted sideways, nearly into the plane of its revolution about the Sun. Its moons orbit in the planet’s equatorial plane and are thus subject to extreme seasonal cycles, with the poles of some being plunged into continuous darkness for decades followed by equally long periods of sunlight. Like all of the gas giants, it has a set of planetary rings. Uranus has 27 known natural satellites. Its five major moons are Miranda, Ariel, Umbriel, Titania, and Oberon.


Miranda moon

Miranda is the smallest and innermost of Uranus’s five major moons. Its surface is possibly composed primarily of water ice. Its dramatically-scarred surface is dominated by scarps, craters, coronae (which may’ve formed via extensional processes at the tops of diapirs) and graben formed by extensional faulting.

Level 18 of Descent takes place on Miranda.


Oberon moon

Oberon is the outermost major moon of the planet Uranus and the second largest and second most massive of the Uranian moons. Oberon is composed of approximately equal amounts of ice and rock –probably differentiated into a rocky core and an icy mantle which are possibly separated by a layer of liquid water. Its unnamed, highest peak is believed to be taller than Mauna Kea and Mauna Loa, Earth’s tallest mountains.

In the Russian film, Лунная радуга (Moonlight Rainbow), cosmonauts on Oberon are infected with a disease that gives them supernatural powers. On Doctor Who, the series “Revelation of the Daleks” introduces the Grand Order of Oberon. In the Canadian television series, Starhunter, the episode “Cell Game” establishes that Oberon is home to a penal colony. Three levels of Descent take place on Oberon. In Reality Pump Studios‘ game, Earth 2160, some of the action takes place on Oberon.


Titania moon

Titania is the largest of the moons of Uranus and the eighth largest moon in the Solar System. Titania consists of approximately equal amounts of ice and rock, with an icy mantle and rocky core. As on Oberon, a layer of liquid water may be present at the core–mantle boundary.

In Earth 2160 references are made to a destroyed prison colony on Titania.



Neptune high resolution

Neptune is the eighth and most distant planet from the Sun in the Solar System. Methane in the outermost regions in part account for the planet’s striking blue appearance (Uranus has similar levels of methane but it more cyan than azure so there must be other factors behind its brilliant blue). Neptune frequently experiences massive anti-cyclonic storms. Neptune has thirteen known moons.


Triton moon high resolution

Triton is by far the largest (and most interesting) of Neptune’s satellites, comprising more than 99.5% of all of the planet’s orbiting mass. It’s also the only moon massive enough to be spheroidal. In fact, its size, shape and retrograde orbit indicate that’s a captured object and was once probably a dwarf planet. In fact, it’s the only large moon with retrograde orbit in the Solar System. It’s also one of the few geologically active moons, which accounts for its young, smooth complexion. Along with Ganymede, it’s the only moon larger than the smallest planet (again, Mercury).

And finally, Triton is the setting for level 23 of, you guessed it, Descent.


Support Eric Brightwell on Patreon

Eric Brightwell is an adventurer, essayist, rambler, explorer, cartographer, and guerrilla gardener who is always seeking paid writing, speaking, traveling, and art opportunities. He is not interested in generating advertorials, cranking out clickbait, or laboring away in a listicle mill “for exposure.”
Brightwell has written for Angels Walk LAAmoeblogBoom: A Journal of CaliforniadiaCRITICSHidden Los Angeles, and KCET Departures. His art has been featured by the American Institute of Architects, the Architecture & Design Museum, the Craft ContemporaryForm Follows FunctionLos Angeles County Store, the book SidewalkingSkid Row Housing Trust, and 1650 Gallery. Brightwell has been featured as subject in The Los Angeles TimesHuffington PostLos Angeles MagazineLAistCurbedLAEastsider LABoing BoingLos Angeles, I’m Yours, and on Notebook on Cities and Culture. He has been a guest speaker on KCRW‘s Which Way, LA?, at Emerson College, and the University of Southern California.
Brightwell is currently writing a book about Los Angeles and you can follow him on AmebaDuolingoFacebookGoodreadsInstagramMubiand Twitter.


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