Gallery: The Most Badass Moons in the Solar System
01mimas
The solar system is stuffed with mighty moons. Some are tiny, some are enormous. One is a raging volcanic inferno, others create rings around their planets. One has a giant ocean that could be home to extraterrestrial plesiosaurs. Another hangs in Earth’s sky every evening. And others have bizarre landscapes, lakes, and geysers. But which is the most badass? Enceladus is the astrobiology It-Moon of the moment, but can it be beaten in a satellite smackdown? Vote (below) for your favorite from this list — or let us know which we’ve forgotten. [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/death-star-mimas.jpg) __Above:__ Mimas: A Giant Death Star ------------------------- __Planet:__ Saturn __Diameter:__ 396 km __Date of Discovery:__ 1789 (William Herschel) __Most Badass Feature:__ It's Darth Vader's weapon of choice. Mimas looks exactly like the Death Star. What better evidence of badassness could you possibly find? *Images: 1) NASA/JPL/Space Science Institute. 2) Lucasarts.*
02europa
Europa: Icy Abode of (Possible) Life ------------------------------------ __Planet:__ Jupiter __Diameter:__ 3,100 km __Date of Discovery:__ 1610 (Galileo Galilei) __Most Badass Feature:__ Potential alien abode Scientists are pretty sure that beneath Europa's icy exterior is an ocean with almost twice the water that Earth has (and our planet is covered in water). Given that we know our own oceans to be teeming with organisms, most people are convinced that Europa is among the top contenders to find wriggling alien creatures somewhere other than Earth. All we need to do is invent a deep-drilling deep space robot that can crunch through the moon's 100-km-thick crust and scope out the surroundings. There are even hints that the ice shell is much thinner in places, where [enormous lake-like reservoirs](http://stag-komodo.wired.com/wiredscience/2011/11/lake-europa/) wait a mere 3 km below the surface. Even if Europa had no life, its place in the lunar badass hall of fame would be secure by virtue of it being one of the largest moons in the solar system. It's covered in beautiful cracks that make it look like some insane tattoo artist went to town on the place. And it gets the best shoutout in all of science fiction with when the god-like aliens of *2010: Odyssey Two* tell humanity: "All these worlds are yours, except Europa. Attempt no landings there." [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/europagalieleo.jpg) *Images: 1) [NASA/JPL](http://photojournal.jpl.nasa.gov/catalog/PIA01503) 2) [NASA/JPL/University of Arizona/University of Colorado](http://photojournal.jpl.nasa.gov/catalog/PIA03878)*
03io
Io: The Realm of Raging Volcanoes --------------------------------- __Planet:__ Jupiter __Diameter:__ 3,642 km __Date of Discovery:__ 1610 (Galileo Galilei) __Most Badass Feature:__ It’s a moon. With hundreds of active volcanoes. [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/io970321_gal_big.jpg) You think saltwater geysers are special? Wait until you meet this moon. Io is the most geologically active object in the solar system. The moon’s surface is [pockmarked with more than 400 volcanoes](http://stag-komodo.wired.com/wiredscience/2012/03/jupiter-io-moon-map/) — many of which erupt simultaneously. The extraterrestrial eruptions send plumes of sulfur and ash hundreds of kilometers into space and painting the moon in shades yellow, red, green, white, and black. Don't believe us? Check out this eruption from the moon's Tvashtar region (animation above), captured by the New Horizons spacecraft. That plume is 330 kilometers tall. Also, there are icy sulfur-bergs. And, when charged particles from Io’s volcanoes (see close-up, below) slam into Jupiter’s magnetosphere, [they create auroras](http://onlinelibrary.wiley.com/doi/10.1029/2011GL050253/abstract) – shimmering lights at the giant planet’s poles. [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/iovol1.jpg) *Images: 1) [The Galileo Project/NASA/JPL](http://apod.nasa.gov/apod/ap970321.html) 2) [NASA/Voyager Project/Calvin Hamilton](http://apod.nasa.gov/apod/ap950804.html)* *Animation: NASA/[Wikipedia](http://en.wikipedia.org/wiki/File:Tvashtarvideo.gif)*
04enceladus
Enceladus: Giant Plumes of Life (Maybe) --------------------------------------- __Planet:__ Saturn __Diameter:__ 504 km __Date of Discovery:__ 1789 (William Herschel) __Most Badass Feature:__ Cryovolcanoes The argument for Enceladus being Saturn's most badass moon isn't even worth making. It's so obvious. But here's why it is the most badass in the solar system: It's not just one of the [best candidates for life](http://stag-komodo.wired.com/wiredscience/2008/12/enceladus/) beyond Earth, it is [spewing plumes](http://stag-komodo.wired.com/wiredscience/2012/05/enceladus-plumes/) of the evidence of this into space through cryovolcanoes. The icy surface of Enceladus is covering a hidden subsurface ocean that scientists believe may contain the ingredients necessary to harbor life. In addition, the surface is covered with cracks and folds and "tiger stripes" that get geologists all worked up. And it doesn't hurt that the most badass space probe has taken so many [awesome shots of this moon](http://stag-komodo.wired.com/wiredscience/2010/02/gallery-enceladus/). [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/enceladus-rise.jpg) *Images: NASA/JPL/Space Science Institute.*
05hyperion
Hyperion: Land of the Honeycomb ------------------------------- __Planet:__ Saturn __Diameter:__ 270-ish km __Date of Discovery:__ 1848 (William Bond, George Bond, William Lassell) __Most Badass Feature:__ Deep, sharp-edged craters that make it look like a giant angry space wasp nest Some of these craters have names like [Bahloo and Jarilo](http://planetarynames.wr.usgs.gov/SearchResults?target=HYPERION&featureType=Crater,%20craters). Scientists think Hyperion is a loose rubble pile held together by gravity. It has a fairly low density, suggesting that it's composed mostly of water ice with a bit of rock thrown in for good measure. Hyperion also rates as the moon most likely to be a good exfoliant if you printed a tiny model of it and kept it in your shower. *Image: [NASA/JPL/Space Science Institute](http://photojournal.jpl.nasa.gov/catalog/PIA07761)*
06iapetus
Iapetus: A Cranky, Mysterious Moon ---------------------------------- __Planet:__ Saturn __Diameter:__ 1,468 km __Date of Discovery:__ 1671 (Giovanni Domenico Cassini) __Most Badass Feature:__ Huge, mysterious equatorial mountain range Two-toned Iapetus is Saturn’s weirdest and most mysterious moon. One half of the moon is white, the other is black. It’s squashed and shaped like a walnut. There are [huge, icy avalanches.](http://stag-komodo.wired.com/wiredscience/2012/07/iapetus-ice-avalanches/) And running straight as an arrow along 75 percent of the moon's bulging equator is [an enormous mountain range](http://stag-komodo.wired.com/wiredscience/2012/12/iapetus-ridge-theory/) with peaks stretching 20 kilometers high, the likes of which have never been seen anywhere else. [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/iapetusterrain_cassini.jpg) *Images: 1) [NASA/JPL/Space Science Institute](http://photojournal.jpl.nasa.gov/catalog/PIA06166) 2) [NASA/JPL/Space Science Institute](http://www.nasa.gov/mission_pages/cassini/multimedia/pia08372.html)*
07charon
Charon: The Almost-Planet ------------------------- __(Dwarf) Planet:__ Pluto __Diameter:__ 1,206 km __Date of Discovery:__ 1978 (James W. Christy) __Most Badass Feature:__ The main moon of an inherently badass planet Named after the mythological boatman who ferried doomed souls across the river Styx, Charon is Pluto’s largest moon. At roughly half the diameter of Pluto, the moon is so big that it [basically forms a binary planet](http://news.discovery.com/space/is-charon-a-moon-of-pluto-or-a-binary-planet-120715.htm) with its dwarfish host. In fact, the pair orbits a center of mass that lies between the two objects, rather than inside Pluto. Though there aren’t any fantastic images of this moon-with-delusions-of-grandeur, there will be soon. In 2015, when NASA’s [New Horizons probe](http://pluto.jhuapl.edu) swings by the system, we can expect to see Charon — and its underworldly friends — in detail. Charon is joined by moons Nix and Hydra, as well as tiny runt satellites P4 and P5, [still awaiting names](http://stag-komodo.wired.com/wiredscience/2013/02/name-plutos-tiniest-moons/). Could the two small moons soon be named [Vulcan and Cerberus](http://www.plutorocks.com/current-tally)? If the results of a recent popular vote are any indication, it appears that the cast of characters will soon include a three-headed dog and the Roman god of lave and smoke. Charon could still kick both their asses. [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/Pluto_and_charon.jpg) *Images: 1) Lanthanum-138/[Wikimedia](http://commons.wikimedia.org/wiki/File:Charon.png), based on [Mapping the surface of Pluto and Charon](http://www.boulder.swri.edu/~buie/pluto/plutomap1.html) 2) [Dr. R. Albrecht, ESA/ESO Space Telescope European Coordinating Facility; NASA](http://hubblesite.org/newscenter/archive/releases/1994/17/image/a/)*
08triton
Triton: Geysers at the Solar System's Edge ------------------------------------------ __Planet:__ Neptune __Diameter:__ 2,700 km __Date of Discovery:__ 1846 (William Lassell) __Most Badass Feature:__ Active tectonics and cryovolcanoes Though moons like Enceladus hog all the attention with their spectacular geysers, Triton gets no love. Maybe that's because it's at the very edge of the solar system and hardly anyone remembers it even exists. But Triton's cryovolcanoes are incredibly alien, spewing out nitrogen and keeping the surface free of any blemishing impact craters. No one exactly understands how Triton's active volcanism works, especially considering that its surface temperature is only slightly above absolute zero. Instead of molten rock, water and ammonia flow over its face, carving complex valleys and ridges. Vast swathes of the moon are also covered in weird, mottled plains resembling cantaloupe peel. The bizarre cantaloupe terrain is completely unlike anything else in the solar system, and is thought to form when lumps of material rise upward through a layer of denser surface. Only one probe, Voyager 2, has ever ventured anywhere near the frozen moon. *Image: [NASA/JPL/USGS](http://photojournal.jpl.nasa.gov/catalog/PIA00317)*
09the-moon
The Moon: Earth's Constant Companion ------------------------------------ __Planet:__ Earth __Diameter:__ 3,474 km __Date of Discovery:__ Unknown. __Most Badass Feature:__ It’s the only extraterrestrial object humans have walked on. [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/apollo11_footprint_big.jpg) About 4.5 billion years ago, Earth collided with a Mars-size object. The cataclysm shot a flaming ball of debris into space -- a fiery, roiling mass that eventually became the moon. Over time, the satellite's nascent magma oceans solidified. Asteroids pummeled its surface. And out of fire came the dusty, gleaming white surface that man eventually pressed his moon boots into. Now, the moon hangs serenely in Earth’s skies, our planet’s nearest neighbor and perpetual companion, an inspiration for mystics and poets, and a tease for the optimists who wish it were made of cheese. But though it's nearby, the moon still holds many mysteries, and scientists are working hard to solve its riddles. As NASA's Juno spacecraft made its way toward Jupiter, it took a minute to capture this image of the celestial pair. [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/583510main_juno20110830-full.jpg) *Images: 1) [NASA/JPL](http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=9763) 2) [NASA](http://www.nasa.gov/audience/forstudents/k-4/stories/who-was-neil-armstrong-k4_prt.htm) 3) [NASA/JPL/SwRI](http://www.nasa.gov/mission_pages/juno/news/juno20110830.html)*
10asteroid-moons
Asteroid Moons -------------- __Planet:__ None __Diameter:__ Variable __Date of Discovery:__ First confirmed in 1993 (around 243 Ida) __Most Badass Feature:__ Umm. They orbit asteroids. Mooneroids: Moons orbiting asteroids. Space rock thugs. Bodyguards. You know asteroids with moons are wandering around thinking they’re all awesome because they’ve got an entourage. [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/243_ida.jpg) *Image: 243 Ida and Dactyl, [NASA/JPL](http://photojournal.jpl.nasa.gov/catalog/?IDNumber=PIA00069)* *Animation: (136617) 1994 CC, [NASA](http://www.nasa.gov/images/content/376755main_neo20090806-516.gif)*
11phoebe
Phoebe: The Black Sheep ----------------------- __Planet:__ Saturn __Diameter:__ 212 km __Date of Discovery:__ 1898-1899 (W.H. Pickering) __Most Badass Feature:__ It creates a huge, nearly invisible ring around Saturn. [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/Saturn_largest_ring_Spitzer_telescope_20091006.jpg) Phoebe is the rogue moon in the Saturnian system. It orbits the planet backward. Cratered and oddly shaped, the moon is most likely an icy, tiny seed that never grew into a planet. Then one day, Phoebe left its home in the Kuiper Belt, and wandered too close to the great ringed world. Saturn snared it. Now Phoebe flings dark dust into the space around its new home. (In fact, the moon is the source of Iapetus’ darkened face.) And not just a little bit. Debris coming from the moon creates an enormous ring around Saturn (see illustration, right) — a ring so big and so dark that astronomers didn’t even know it was there until 2009. *Images: 1) [NASA/JPL/Space Science Institute](http://photojournal.jpl.nasa.gov/catalog/PIA06064) 2) [NASA/JPL-Caltech/Keck](http://en.wikipedia.org/wiki/File:Saturn_largest_ring_Spitzer_telescope_20091006.jpg)*
12titan-2
Titan: Seasons, Lakes and Life ------------------------------ __Planet:__ Saturn __Diameter:__ 5,150 km __Date of Discovery:__ 1655 (Christiaan Huygens) __Most Badass Feature:__ Enormous, hydrocarbon-filled seas with names like Kraken Mare [](http://stag-komodo.wired.com/images_blogs/wiredscience/2013/02/huygens_titan_04.jpg)Titan has [seasonal vortexes](http://www.nasa.gov/mission_pages/cassini/multimedia/pia14919.html) at its poles, a subterranean ocean, a landscape covered in [hydrocarbon lakes](http://stag-komodo.wired.com/wiredscience/2011/12/titan-lakes-rivers/) and water-ice rocks, [a mighty, Nile-like river](http://stag-komodo.wired.com/wiredscience/2012/12/nile-river-titan/), cryovolcanoes, and the potential to host life. Covered in a dense orange haze, Titan is among the largest moons in the solar system, and the only body other than Earth to continually have liquid on its surface. In fact, the moon is deceptively Earth-like except for its surface chemistry. Finding life in one of Titan’s lakes would be strong evidence for a second genesis: Instead of liquid water, critters would be living in frozen ethane or methane, normally gases but for the exceptionally cold temperature. In 2005, the Cassini-Huygens probe descended through Titan's haze, bounced a few times, slid, and wobbled to rest in a dry (methane) riverbed. Then, as all good spacecraft do, it took a picture (right). *Images: [NASA/JPL/Space Science Institute](http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=2783), [ESA/NASA/JPL/University of Arizona](http://nssdc.gsfc.nasa.gov/planetary/titan_images.html)*
