50 Fun Facts About Moons of Saturn

Saturn's moon Mimas, scarred by one enormous crater, resembles which science-fiction space station?

The Death Star likeness comes from a crater about a third as wide as Mimas itself, on the smallest known body pulled round by its own gravity.

Cassini's heat maps of Saturn's moon Tethys show a pattern shaped like which arcade game character?

Pac-Man shows up in infrared because one stretch of Tethys's surface stays cooler at midday than the ground around it.

In Marvel Comics, which warlord nicknamed the Mad Titan was born on Saturn's largest moon?

Thanos hails from Titan, and his name echoes Thanatos, a label for Freud's idea of a human drive toward destruction, which creator Jim Starlin met in a psychology class.

Mountains on Saturn's moon Titan are named after peaks from which author's fictional world?

J. R. R. Tolkien's Middle-earth gives Titan a Doom Mons and an Erebor Mons, under a naming rule that borrows only fictional mountains.

Saturn's moon Titan is so large that it is wider than which planet of the solar system?

Mercury is about 6% narrower than Titan yet more than twice as massive, because it is iron and rock while Titan is mostly ice.

Titan was thought the solar system's largest moon until 1980, when which rival proved bigger?

Ganymede took the title because Titan's deep haze had padded its apparent size: the solid surface underneath is about 120 km narrower than Ganymede.

Why was the Cassini spacecraft deliberately crashed into Saturn in 2017 as its fuel ran low?

To protect its moons: a dead, drifting Cassini might one day have struck Titan or Enceladus and seeded a possibly habitable world with Earth microbes.

Which European probe, released by Cassini, made the first landing on a moon other than Earth's?

Huygens parachuted onto Titan and kept transmitting for about 90 minutes, three times longer than its engineers had hoped.

Plains on Titan, such as Arrakis Planitia, are named after planets from which science-fiction series?

Dune and its desert world Arrakis suit Titan well: belts of dark sand dunes, some more than 100 km long, wrap around the moon's equator.

Titan is the only moon with air thicker than Earth's; which gas makes up most of that atmosphere?

Nitrogen makes up about 95% of the air at Titan's surface, where the pressure is roughly one and a half times that at sea level on Earth.

Titan is the only world besides Earth with stable lakes and seas; which liquids fill them?

Methane and ethane stay liquid at about −179 °C, so Titan has rain, rivers and seas much as Earth does, with natural gas standing in for water.

Seen from space, the thick haze that hides Titan's surface gives the moon which colour?

Orange smog forms when sunlight breaks up gases high above Titan, and it is so thick that no camera saw the surface clearly until 2004.

Which spacecraft flew close past Titan in 1980, a detour that ended any chance of it visiting Pluto?

Voyager 1 was aimed at Titan because the moon was known to have a substantial atmosphere, and the swing past it flung the craft out of the plane of the planets.

Which NASA mission is designed to fly a robotic rotorcraft from site to site across Saturn's moon Titan?

Dragonfly should find flying easy: Titan's air is about four times as dense as Earth's, while its gravity is under a seventh as strong.

Titan's haze blocks ordinary cameras, so which instrument did Cassini use to map its lakes and seas?

Radar pulses pass straight through the smog, and their echoes off the sea floor let scientists measure how deep Titan's seas are.

Titan always shows Saturn the same face, as the Moon does to Earth, because of which effect?

Tidal locking also raises a permanent bulge of about 100 metres on the sides of Titan that face toward and away from Saturn.

In 2019, twenty new discoveries lifted Saturn past which planet as the one with the most known moons?

Jupiter had led the count since 2000, and another 62 moons announced in May 2023 pushed Saturn's total past 140.

Which small moon of Saturn is named after the first mortal woman of Greek myth, made on Zeus's orders?

Pandora circles just outside Saturn's thin F ring and was long credited with helping to confine it, a job her inner neighbour now seems to do alone.

Which moon of Saturn, named after the Titan who stole fire, tugs streamers of material out of the F ring?

Prometheus dips into the ring's inner edge on each orbit, pulling out a streamer of material and leaving a dark channel behind.

Which moon of Saturn is two-toned, with a dark leading hemisphere and a bright trailing hemisphere?

Iapetus also wears a mountain ridge around its equator, with peaks more than 20 km high, that makes the whole moon look like a walnut.

Which sponge-like moon of Saturn tumbles so chaotically that its spin cannot be predicted?

Hyperion was the first moon ever found that is not round, and it is so porous that roughly 40% of its volume is empty space.

Which outer moon of Saturn orbits backwards and was the first moon ever discovered using photography?

Phoebe sheds the dust of a vast, nearly invisible ring found around Saturn in 2009, which circles the planet backwards just as the moon does.

Which moon, named after the mother of Zeus and his siblings, is the second-largest of Saturn's moons?

Rhea is still less than a third as wide as Titan, and Cassini found it wrapped in a whisper-thin atmosphere of oxygen and carbon dioxide.

Which moon of Saturn, named after a two-faced Roman god, swaps orbits with a neighbour every four years?

Janus and its partner never come closer than about 10,000 km: as one catches up, their gravity trades momentum and the two switch lanes.

Which tiny moon at the edge of Saturn's A ring is named after the Titan who held up the sky?

Atlas got the name because it seemed to hold the rings on its shoulders, and a smooth ridge around its equator makes up about a quarter of its volume.

Which ravioli-shaped moon of Saturn keeps the Encke Gap in the A ring swept clear of particles?

Pan was predicted before it was seen: wavy edges on the gap betrayed a hidden moon, later found in old photos within 1° of the forecast spot.

Ice sprayed into space by geysers on Enceladus builds which of Saturn's rings?

The E ring is vast yet nearly invisible: it stretches from the orbit of Mimas out to Titan and is more than 2,000 km thick.

What did Cassini find hidden beneath the icy crust of Enceladus, feeding the jets at its south pole?

A saltwater ocean wraps the entire moon beneath the ice: Enceladus wobbles slightly as it orbits, which shows its crust floats free of the rocky core.

The four long fractures at the south pole of Enceladus, where its jets erupt, are nicknamed what?

Tiger stripes are far warmer than sunlight alone could make them, with spots near −116 °C amid ice below −180 °C, so the heat must come from inside.

Fresh snow from its own geysers gives Saturn's moon Enceladus which solar-system record?

Most reflective body it is: Enceladus bounces back nearly all the sunlight that hits it, so its surface at noon is a frigid −198 °C.

Cassini flew through the plumes of Enceladus and found which gas, a possible food for microbes?

Hydrogen in the jets is a sign of chemical reactions with rock deep inside the moon, the kind that feed microbes around vents on Earth.

Craters and valleys on Enceladus are named after characters and places from which collection of tales?

The Arabian Nights gives Enceladus craters called Aladdin and Ali Baba, with every name drawn from Richard Burton's Victorian translation.

Almost every crater on Saturn's moon Mimas is named after a character from which medieval story cycle?

Arthurian legend supplies craters called Arthur, Merlin and Galahad; the lone exception honours the astronomer who discovered Mimas.

Which astronomer gave Saturn's first seven known moons their mythological names in 1847?

John Herschel proposed the names while writing up his observations from South Africa; his father William had discovered two of the seven moons.

Giovanni Cassini named the four moons of Saturn he discovered in honour of which French king?

Louis XIV was honoured in Latin as Sidera Lodoicea, the stars of Louis, a label later dropped for the Greek-myth names used today.

Saturn's outer moons Ymir, Fenrir and Skoll are named after giants and wolves of which mythology?

Norse names go to the moons of Saturn's largest outer family, whose members all orbit in the opposite direction to the planet's spin.

Saturn's moons Kiviuq, Ijiraq and Siarnaq are named after figures from which people's legends?

The Inuit names mark a family of moons with similarly tilted orbits, the largest of which, Siarnaq, is only about 39 km across.

Saturn's moons Albiorix, Tarvos and Erriapus are named after gods of which ancient people?

The Gauls lend their gods to a small family of moons whose orbits tilt between about 34° and 41°, led by 29-km Albiorix.

At Saturn, a small satellite whose gravity keeps a ring's edge sharp is called what?

A shepherd moon can open a whole gap, as one does in Saturn's A ring, or pin a strand in place, as one does beside the narrow F ring.

Hidden moonlets in Saturn's A ring reveal themselves by stirring up disturbances shaped like what?

Propellers several kilometres long are all Cassini could see: the moonlets that make them are only about a hundred metres across.

A bright region of Titan the size of Australia is named after which fabled place in a Coleridge poem?

Xanadu was spotted by the Hubble Space Telescope in 1994, a decade before any spacecraft arrived to peer through Titan's haze and confirm it.

Which astronomer, namesake of a belt of icy bodies beyond Neptune, detected Titan's atmosphere in 1944?

Gerard Kuiper split Titan's light into a spectrum and found the fingerprint of a gas, proof that the moon had air of its own.

Carl Sagan coined which word for the gunky organic solids formed in Titan-like gas mixtures?

Tholins take their name from a Greek word for muddy, chosen by Sagan and his colleague Bishun Khare for the residue of their experiments.

In 2022, MIT scientists proposed that Saturn's rings are the wreck of a lost moon they named what?

Chrysalis was named for a butterfly's pupa: about 99% of the moon is thought to have fallen into Saturn, with the rest emerging as the rings.

Dozens of Saturn's small outer moons were found with the Subaru telescope on which Hawaiian volcano?

Mauna Kea's Subaru telescope pairs an 8.2-metre mirror with a wide-field camera, a combination able to pick out extremely faint moons.

Which moon of Saturn, named after the nymph who detained Odysseus, follows Tethys in the same orbit?

Calypso sits 60 degrees behind Tethys at a gravitational balance point, making it what astronomers call a trojan moon.

In Greek myth, the giant Enceladus, namesake of Saturn's moon, was said to lie buried under which volcano?

Mount Etna's eruptions were said to be the buried giant's breath, a neat fit for a moon that is itself constantly erupting.

Which tiny moon of Saturn raises ripples along the edges of the Keeler Gap as it orbits inside the A ring?

Daphnis was inferred from those ripples before any camera caught it, and it is named after a pipe-playing poet of Greek myth.

Which small moon of Saturn, orbiting between Mimas and Enceladus, is shaped like a smooth egg?

Methone may be coated in an icy fluff loose enough to flow, which would explain why the little moon shows no craters at all.

William Pickering announced a tenth moon of Saturn in 1905 that never existed; what did he name it?

Themis was never seen by anyone else, though Pickering went as far as computing its orbit and estimating it at 38 miles wide.