Jupiter's+Satellites

Jupiter has 63 known moons. Jupiter's 4 largest moons, Callisto, Europa, Ganymede and Io, exhibit some of the most interesting geology in the solar system. They were discovered by Galileo Galilei and are known as the Galilean moons. Jupiter's largest moon, Ganymede, is larger than Mercury while the other three are larger than Pluto.

**Callisto **

**Europa **
 * Composition: The exact composition of Callisto's [|rock] component is not known, but is probably close to the composition of L/LL type [|ordinary chondrites], which are characterized by less total [|iron], less metallic iron and more [|iron oxide] than [|H chondrites].
 * Size: 4821 km
 * Density: 1.86 grams/cubic cm
 * Orbit: an average orbital radius of 1,882,700 km and an orbital period of 16.69 days
 * Surface features: Callisto is the most heavily cratered object in the solar system. It is thought to be a long dead world, with hardly any geologic activity on its surface.
 * Tectonic activity: none
 * Surface temperature: -279° F (-172° C)
 * Suitability for life: It is unlikely that any living organisms inhabit Callisto.
 * Additional information: Callisto was originally designated Jupiter IV by Galileo because it is the fourth satellite of Jupiter. Callisto is named for the beautiful daughter of Lycaon, who followed Artemis, the chaste goddess of the Moon and the hunt. Unfortunately, Callisto was seduced by Zeus and became pregnant, so she was banished by Artemis as a result. Zeus changed Callisto into a bear to protect her from his wife Hera's jealousy. Later, Zeus placed Callisto and their son in the sky, where mother and son became Ursa Major and Ursa Minor (Great Bear and Little Bear).

**Ganymede **
 * Composition: Europa is somewhat similar in bulk composition to the other terrestrial planets (primarily composed of silicate rock). Recent data from Galileo indicate that Europa has a layered internal structure perhaps with a small metallic core. However, Europa's surface is not at all like anything in the inner solar system. Its surface is exceedingly smooth with few features more than a few hundred meters high.
 * Size: 3122 km
 * Density: 3.0 grams/cubic cm
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Orbit: an average orbital radius of 671,100 km and orbital period of 3.55 days.
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Surface features: Europa shows surface features such as domes and ridges, as well as a region of disrupted terrain including crustal plates which are thought to have broken apart and "rafted" into new positions.
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Tectonic activity: tectonically active and young
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Surface temperature: at the equator never rises above -260° F (-160° C); at the poles, never rises above -370° F (-220° C).
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Suitability for life: There is a possibility that life exists on Europa, it has the potential.
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Additional information: Europa was originally designated Jupiter II by Galileo because it was the second satellite of Jupiter. Europa is named for the daughter of Agenor. She was abducted by Zeus (the Greek equivalent of Jupiter), who had taken the shape of a spotless white bull. Europa was so delighted by the gentle beast that she decked it with flowers and rode upon its back. Zeus seizing his opportunity rode away with her into the ocean to the island of Crete, where he transformed back into his true shape. Europa bore Zeus many children, including Minos.


 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Composition: Ganymede is composed of nearly equal amounts of silicate rock and water ice and has an iron-rich, liquid core, thought to be responsible for its magnetic field. Scientists think that a saltwater ocean lies about 200 km below the surface, floating between layers of ice. There are two types of surface on Ganymede: dark regions and lighter regions.
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Size: 5262 km
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Density: 1.93 grams/cubic cm
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Orbit: an average orbital radius of 1,070,400 km and orbital period of 7.16 days
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Surface features: In 2004, scientists discovered irregular lumps beneath the icy surface of Ganymede. The irregular masses may be rock formations, supported by Ganymede's icy shell for billions of years. This tells scientists that the ice is probably strong enough, at least near the surface, to support these possible rock masses from sinking to the bottom of the ice. However, this anomaly could also be caused by piles of rock at the bottom of the ice. Spacecraft images of Ganymede show the moon has a complex geological history. Ganymede's surface is a mixture of two types of terrain. Forty percent of the surface of Ganymede is covered by highly cratered dark regions, and the remaining sixty percent is covered by a light grooved terrain, which forms intricate patterns across Ganymede. The term "sulcus," meaning a groove or burrow, is often used to describe the grooved features. This grooved terrain is probably formed by tensional faulting or the release of water from beneath the surface
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Tectonic activity: Ganymede does show signs of tectonic activity. But the surface is also covered by craters, indicating any tectonic activity was long ago.
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Surface temperature: -171° F to -297° F (during the day); -193° C (during the night)
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Suitability for life: It is unlikely that any living organisms inhabit Ganymede.
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Additional information: In mythology, Ganymede ("GAN uh meed") was a beautiful young boy who was carried to Olympus by Zeus (the Greek equivalent of Jupiter) disguised as an eagle. Ganymede became the cupbearer of the Olympian gods.


 * <span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 110%; text-align: justify;">Io **


 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Composition: Io's colorful appearance is the result of various materials produced by its extensive volcanism. These materials include [|silicates] (such as [|orthopyroxene]), [|sulfur], and [|sulfur dioxide].
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Size: 3643 km
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Density: 3.55 grams/cubic cm
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Orbit: average orbital radius of 421,800 km and orbital period of 1.77 days.
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Surface features: This tidal pumping generates a tremendous amount of heat within Io, keeping much of its subsurface crust in liquid form seeking any available escape route to the surface to relieve the pressure. Thus, the surface of Io is constantly renewing itself, filling in any impact craters with molten lava lakes and spreading smooth new floodplains of liquid rock.
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Tectonic activity: Although there is no direct evidence of tectonic activity on Io, scientists feel confident it exists since the processes that fuel volcanism also fuel tectonics. The volcanic eruptions are so frequent and cover the surface so thoroughly that any clear evidence of tectonic activity is likely to be buried.
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Surface temperature: about -202° F; volcanoes can reach 3,000° F
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Suitability for life: It is unlikely that any living organisms inhabit Io.
 * <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; vertical-align: sub;">Additional information: Io was originally designated Jupiter I by Galileo because it is the first satellite of Jupiter. Io is named for the daughter of Inachus, who was raped by Jupiter (the Roman counterpart of Zeus). Jupiter, in an effort to hide his crime from his wife, Juno (the Roman counterpart of Hera), transformed Io into a heifer.


 * <span style="color: #000080; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 90%; text-align: left; vertical-align: super;">Works Cited **


 * <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 90%; text-align: justify; vertical-align: sub;">"Jupiter’s Moon Ganymede." Universe Today — Space and astronomy news. N.p., n.d. Web. 1 May 2013. <http://www.universetoday.com/15205/jupiters-moon-ganymede/#ixzz2RQKvQTn9>.
 * <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 90%; text-align: justify; vertical-align: sub;">"Moons of Jupiter." Lunar calendar, moon phases and space weather. N.p., n.d. Web. 1 May 2013. <http://lunaf.com/english/live-data/jupiter-moons-position/>.
 * <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 90%; text-align: justify; vertical-align: sub;">"Solar System Exploration: Planets: Jupiter: Moons: Callisto: Overview." Solar System Exploration. N.p., n.d. Web. 1 May 2013. <http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Callisto>.
 * <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 90%; text-align: justify; vertical-align: sub;">"Solar System Exploration: Planets: Jupiter: Moons: Europa: Overview." Solar System Exploration. N.p., n.d. Web. 1 May 2013. <http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Europa>.
 * <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 90%; text-align: justify; vertical-align: sub;">"Solar System Exploration: Planets: Jupiter: Moons: Ganymede: Overview." Solar System Exploration. N.p., n.d. Web. 1 May 2013. <http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Ganymede>.
 * <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 90%; text-align: justify; vertical-align: sub;">"Solar System Exploration: Planets: Jupiter: Moons: Io: Overview." Solar System Exploration. N.p., n.d. Web. 1 May 2013. <http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Io>.