Jupiter Images Menu Shoemaker - Levy 9 Impacts Jupiter MENU Jupiter's moon Io has many active volcanoes. It's surface is one of the youngest in the Solar System (it rivals only the Earth). This picture taken by Voyager 2 in July 1979, shows two color-enhanced (blue) volcanic plumes erupting to heights of 100 km above the surface. Io is about the same size as Earth's Moon. (Courtesy NASA/JPL) Jupiter on February 13, 1979. Voyager 1 was approaching the giant planet and captured this view showing the Great Red Spot, the satellite Io (orange moon on left), and Europa (brighter moon on right). (Courtesy NASA/JPL). Callisto seen by Voyager 1 in March 1979. Callisto is about the size of the planet Mercury . It is a heavily-cratered moon, which contrasts starkly with Io. Io's surface is as young as Callisto's is old. Callisto probably consists of a mixture of ice and rock.

When the Galileo spacecraft begins studying Jupiter's system in 1995-1997, some parts of Callisto are planned to be imaged at much higher resolution (greater detail) than was available from the Voyagers. Satellites of Jupiter Satellites of Jupiter Sixteen of the larger satellites of Jupiter are denoted in the Table below, where it is seen that the ratios of their distances from the giant planet are given in terms of the Golden Mean , F (or f), as well as Fn, ï¿½2, and e/2 -- the latter being the base of the natural log and one of the three Transcendental Number s . This is particularly true of the so-called Galilean satellites (Io, Europa, Ganymede, and Callisto), which have a very strong F connection in their respective distances from the planet. 153 .0000ï¿½ The degree to which Jupiterï¿½s satellites fall into four groups of four satellites is really quite phenomenal and exceptionally quantum-like in the partiality to certain energetic levels or orbits.

The is particularly true when one realizes that the grouping is by: 1) distance from Jupiter, 2) eccentricity of orbits, 3) inclination of orbits, and 4) approximate size. (On the other hand, Saturnï¿½s satellites connect with F on only two or three occasions, do not display the same quantum grouping as Jupiter, and appear to be obeying some other -- possibly quantum -- connection(s).) There is, of course, the possibility that a captured body split into four bodies due to the gravitational attraction of Jupiter (something like the breaking up of Comet Shoemaker Levy into 22 pieces). But four sets of four? And how does this explain the connection between the four sets of satellites? The big four are, of course, the Galilean Satellites, which were named after their discover (and which constituted the first observational evidence in favor of Copernicusï¿½ radical, heretical theory that the Sun was the center of our planetary system, and that it was the Earth revolving about the Sun rather than the other way around). In many respects the other satellites are not much more than large rocks -- and even possibly asteroids captured from one of the asteroid belts by the gravitational or other attractive qualities of Jupiter.

But even if captured asteroids, why would they gravitate to a particular orbital pattern!? As for the relative distances from Jupiter, we can begin with the Big Four: Europa / Io Naiad SEE figure of different sizes, Encyclopedia of Solar System, p. 436. Outer planet icy satellites are any of the celestial bodies in orbit around Jupiter, Saturn, Uranus, Neptune, or Pluto. All composed mainly of some frozen volatile, usually water ice May also be methane, carbon dioxide, or sulfur dioxide at least 60 satellites (more undoubtedly exist, we just haven't found them yet!) I.

History none was known until after the invention of the telescope 1610: Galileo found 4 Jovian satellites ("Galilean satellites": Io, Europa, Ganymede, and Callisto) best early evidence for Sun-centered (heliocentric) solar system 1655: Huygens found Titan 1680's: Cassini found Rhea, Iapetus, Dione, Tethys 1980's and 1990's: small satellites found in Pioneer and Voyager flybys most recently, U1 and U2 discovered in 1997 around Uranus International Astronomical Union names them... Generally named after figures in mythologies associated with planet's name SURFACE FEATURES also assigned... e.g., Iapetus = people and places from Chanson de Roland (medieval French) Mimas = people and places from Malory's Le Morte d'Arthur Ganymede = Gods, heros and places from ancient Egypt Rhea = people, places from African, Asiatic, S. American creation myths Miranda = humans from Shakespeare's The Tempest, his place names II.

Physical Properties motion of a satellite around a primary defines an ellipse with three elements: 1. semimajor axis 2. eccentricity = departure of orbit from circle 3. angle of inclination intersection btwn plane of orbit and plane of spin equator regular orbit = prograde = same direction as primary also low eccentricity and inclination majority of satellites irregular orbit = retrograde = opposite sense of motion or highly eccentric or highly inclined most believed to be captured objects SEE Encyclopedia of the Solar System, p. 439, for summary table most satellites present same hemisphere toward their primaries 1. gravitational force exerted on near side > far side therefore, you get a bulge/distortion which lags behind rotation 2. synchronous rotation occurs as satellite rotates, the bulge moves with respect to the satellite this induces internal friction, which creates heat spin rate is sacrificed to create heat, so rotation slows longest axis of bulge locks onto line btwn primary and satellite because that's the lowest energy state happens very quickly, so most satellites are in synch. rotation 10,000-10 my.

when close to primary, rotation lags (falls behind) satellite is moving faster so rotation can't keep up when farther from primary, rotation leads satellite is moving slower, rotation is too fast once believed to be dead worlds w/o heat sources recent work has re-written the book tidal interactions provide heat sources non-H2O ice components change melting points and viscosities III. Satellite Formation think back to formation of solar system... denser materials toward center (e.g., Si, Al, Fe, Ti, Ca, etc. on Moon) so inner planet satellites are generally denser outer planet satellites mostly lighter things that condensed at colder T C-based material makes up Phobos and some Saturnian and Jovian ice+silicates form most Jovian satellite (except Io, which has lost H2O) Saturnian and Uranus are: ice+silicates+methane (CH4) + ammonia(NH3) Neptune and Pluto: solid forms of N, carbon monoxide (CO), and dioxide (CO2) contaminants lower the melting temperature of the ice e.g., salts, ammonia, methane, sulfates, carbonates ASK THE STUDENTS: How close can you have a satellite?

satellites can't accrete close to the surface of a planet, because they'll be attracted by gravity to the planet's surface Roche limit = distance (about 2.44 x radius of primary) at which tidal forces exerted on the satellite equal internal gravitation forces of the satellite satellite must be far enough away that tidal forces don't destroy it satellites can't accrete within this limit satellite system form like mini-solar systems (e.g., on Jupiter, Neptune) have density gradients as a function of distance from primary therefore, there's more ice as you get further out from primary BUT this doesn't work on Saturn or Uranus retrograde satellites are captured asteroids left over from planetary formation too small to retain an atmosphere against thermal escape B. Evolution after accretion, satellites began to heat up 1. from release of gravitational potential energy 2. from mechanical release of energy during bombardment e.g., Phobos, Mimas, and Tethys have huge impact craters 3. release of heat from radioactive decay in silicates on larger bodies with lots of silicates, this heat was enough to cause differentiation into core and crust 4.

tidal interactions frictional energy released as heat orbital periods of satellites within a system turn into multiples of each other due to gravitational interactions Io: Europa: Ganymede have 4:2:1 orbits (Fig. 2, p. 242, Beatty et al) this mutual gravity can cause significant heat production TWO types of erosional processes on satellites: 1. Endogenic = internally-produced e.g. volcanism, tectonics, weathering produced by climate 2. Exogenic = brought on by external agents bombardment impact melting darkens and reddens soil leading hemispheres are brighter; higher micrometoerite flux? leading = sides that lead in direction of orbital motion bimodal ice size distribution on leading side 1-2% fine-grained ice, only on leading side trailing side has only one, blocky size of ice interactions with magnetosphere implantation of energetic particles and sputtering volatiles are most susceptible accretion of particles from rings IV. Satellite Observations How do we know what these planets are made of? Spectroscopy... individual minerals absorb at characteristic wavelengths... so, we can detect mineral species AND ice SEE viewgraphs...

heavily cratered terrain crossed by brighter grooved terrain must be differentiated - has a magnetic core and magnetic field 2. Callisto relatively uniform, dark terrain saturated with craters craters >150 km and very small craters are lacking probably due to viscous relaxation i.e., the material's not strong enough to maintain large indentations! covered with loose, particulate matter delivered by meteorites 3. Io most volcanically active body in the solar system! uniform distribution of volcanoes, idicating global source of magma lavas >1200-1300C, maybe as hot at 1500C! much of Io's mantle must be melted... Io has interior of hot crystal/magma mush! about 40% molten surfaces bulges up and down about 100 m crust probably about 100 km thick magma ocean extends down to perhaps 875 km (radius = 1821 km) NO impact craters - rapid resurfacing STILL erupting ; plumes 100 km high!

calderas 300x100 km (vs Kilauea, 8 x 5 km) see PSR Discoveries article on Io, Feb. 2000 4. Europa icy plains crossed by darker fractures - "linea" few impact craters, age 10-100 my So something is actively resurfacing this satellite! crater floors are at same elevation as exteriors very smooth, little topography chaos terrain: rotated blocks of ice several city blocks in size shadows suggest they're 3-5 km thick models say 20-30 km thick probably no melt-through wedges = gaps between plates of ice dark features may be silicate-laden water at the surface thin atmosphere of molecular O (formed by impacts) 1/100 billionth of Earth's atmosphere! gravity data suggest metallic core, rocky interio, 100 km water, 10-15 km ice 2x Earths ocean of water LIFE there? 1. Can life originate without sunlight (photosynthesis)? NO (recent work by Guidos, Kirschvink, et al., Science) 2. Can like survive without sunlight?

MAYBE models of impacts suggest 25% of impacts deliver material there may also be a radiation-driven ecosystem there it'll be hard to detect! Europa Orbiter Mission approved in 2006, arrives 2009 5. Others Adrastea, Metis are just outside the outer edge of the ring, may be sources of it particles probably rock-ice mixtures Lysithea, Elara, Himalia, Leda have highly inclined normal orbits similar to C and D asteroids Sinope, Pasiphae, Carme, Ananke also have inclined orbits retrograde, probably captured asteroids largely water-ice satellites (Voyager flybys 1980-1981) 1. Mimas Herschel is 1/3 of its diameter!!!! surface grooves caused by impact high-rimmed craters suggest little gravity 2. Enceladas very reflective - pure water ice? extensively resurfaced and grooved terrain few impact craters -> surface is less than 1 by old! ice volcanism possible! the other half of the planet is extensively cratered, 4 by may provide particles that form E ring of Saturn 3.

Tethys Odysseus is largest known impact strusture in solar system flatter craters suggest viscous relaxation some regions have fewer craters and higher albedos Ithaca chasm = huge trench one hemisphere is much more reflective than the other don't know if this is endogenic or exogenic highly inclined orbit less dense than other satellites - maybe more ice in its interior? 7. Hyperion covered with ice mixed with dark rocky stuff has highly irregular shape may be in chaotic rotation - perhaps a recent collision? 8. Phoebe dark object, smiliar to C-type asteroids highly inclined, retrograde orbit - captured asteroid? 9. Others shepherding satellites: Atlas, Pandora, Prometeus define Saturn's rings co-orbital Janus and Epimetheus, exchange orbits every 4 years ? maybe were once parts of a larger body Lagrangians: locations within an object's orbit in which a less massive body can move in an identical orbit C.

Uranus major ones are Miranda, Ariel, Umbriel, Titania, Oberon because Uranus' rotational axis is inclined 98 to plane of solar system, these are observed pole-on all composed of water ice, +/- ammonia and methane relatively dark albedo - dark component on surface graphite? How Many Moons Does Jupiter Have? - Universe Today Universe Today How Many Moons Does Jupiter Have? Article Updated: 11 Aug , 2016 by Matt Williams Jupiter was appropriately named by the Romans, who chose to name it after the king of the gods. In addition to being the largest planet in our Solar System – with two and a half times the mass of all the other planets combined – it also has the most moons of any Solar planet. So far, 67 natural satellites have been discovered around the gas giant, and more could be on the way. The moons of Jupiter are so numerous and so diverse that they are broken down into several groups. First, there are the largest moons known as the Galileans, or Main Group. Together with the smaller Inner Group, they make up Jupiter’s Regular Satellites. Beyond them, there are the many Irregular Satellites that circle the planet, along with its debris rings.

Here’s what we know about them… Discovery and Naming: Using a telescope of his own design , which allowed for 20 x normal magnification, Galileo Galilei was able to make the first observations of celestial bodies that were not visible to the naked eye. In 1610, he made the first recorded discovery of moons orbiting Jupiter, which later came to be known as the Galilean Moons . At the time, he observed only three objects, which he believed to be fixed stars. However, between January and March of 1610, he continued to observe them, and noted a fourth body as well. In time, he realized that these four bodies did not behave like fixed stars, and were in fact objects that orbited Jupiter. Portrait of Galileo Galilei by Giusto Sustermans, 1636 . Credit: Royal Museum Greenwhich These discoveries proved the importance of using the telescope to view celestial objects that had previously remained unseen. More importantly, by showing that planets other than Earth had their own system of satellites, Galileo dealt a significant blow to the Ptolemaic model of the universe , which was still widely accepted.

Seeking the patronage of the Grand Duke of Tuscany, Cosimo de Medici, Galileo initially sought permission to name the moons the “Cosmica Sidera” (or Cosimo’s Stars). At Cosimo’s suggestion, Galileo changed the name to Medicea Sidera (“the Medician stars”), honouring the Medici family. The discovery was announced in the Sidereus Nuncius (“Starry Messenger”), which was published in Venice in March 1610. However, German astronomer Simon Marius had independently discovered these moons at the same time as Galileo. At the behest of Johannes Kepler , he named the moons after the lovers of Zues (the Greek equivalent of Jupiter). In his treatise titled Mundus Jovialis (“The World of Jupiter”, published in 1614) he named them Io, Europa, Ganymede, and Callisto. Galileo steadfastly refused to use Marius’ names and instead invented the numbering scheme that is still used today, alongside proper moon names. In accordance with this scheme, moons are assigned numbers based on their proximity to their parent planet and increase with distance.

Hence, the moons of Io, Europa, Ganymede and Callisto were designated as Jupiter I, II, III, and IV, respectively. Drawing of Jupiter made on Nov. 1, 1880 by French artist and astronomer Etienne Trouvelot showing transiting moon shadows and a much larger Great Red Spot. Credit: E.L. Trouvelot, New York Public Library After Galileo made the first recorded discovery of the Main Group, no additional satellites were discovered for almost three centuries – not until E. E. Barnard observed Amalthea in 1892. In fact, it was not until the 20th century, and with the aid of telescopic photography and other refinements, that most of the Jovian satellites began to be discovered. Himalia was discovered in 1904, Elara in 1905, Pasiphaë in 1908, Sinope in 1914, Lysithea and Carme in 1938, Ananke in 1951, and Leda in 1974.

By the time Voyager space probes reached Jupiter around 1979, 13 moons had been discovered, while Voyager herself discovered an additional three – Metis, Adrastea, and Thebe. Between October 1999 and February 2003, researchers using sensitive ground-based detectors found and later named another 34 moons, most of which were discovered by a team led by Scott S. Sheppard and David C. Jewitt. Since 2003, 16 additional moons have been discovered but not yet named, bringing the total number of known moons of Jupiter to 67. Though the Galilean moons were named shortly after their discovery in 1610, the names of Io, Europa, Ganymede and Callisto fell out of favor until the 20th century. Amalthea (aka. Jupiter V) was not so named until an unofficial convention took place in 1892, a name that was first used by the French astronomer Camille Flammarion. Jupiter and its largest moons. Image credit: NASA/JPL The other moons, in the majority of astronomical literature, were simply labeled by their Roman numeral (i.e.

Jupiter IX) until the 1970s. This began in 1975 when the International Astronomical Union’s (IAU) Task Group for Outer Solar System Nomenclature granted names to satellites V–XIII, thus creating a formal naming process for any future satellites discovered. The practice was to name newly discovered moons of Jupiter after lovers and favorites of the god Jupiter (Zeus); and since 2004, also after their descendants. Regular Satellites: Jupiter’s Regular Satellites are so named because they have prograde orbits – i.e. they orbit in the same direction as the rotation of their planet. These orbits are also nearly circular and have a low inclination, meaning they orbit close to Jupiter’s equator. Of these, the Galilean Moons (aka. the Main Group) are the largest and the most well known. These are Jupiter’s largest moons, not to mention the Solar System’s fourth, sixth, first and third largest satellites, respectively. They contain almost 99.999% of the total mass in orbit around Jupiter, and orbit between 400,000 and 2,000,000 km from the planet.

They are also among the most massive objects in the Solar System with the exception of the Sun and the eight planets, with radii larger than any of the dwarf planets. They include Io, Europa, Ganymede, and Callisto, and were all discovered by Galileo Galilei and named in his honor. The names of the moons, which are derived from the lovers of Zeus in Greek mythology, were prescribed by Simon Marius soon after Galileo discovered them in 1610. Of these, the innermost is Io , which is named after a priestess of Hera who became Zeus’ lover. This global view of Jupiter’s moon, Io, was obtained during the tenth orbit of Jupiter by NASA’s Galileo spacecraft. Credit: NASA With a diameter of 3,642 kilometers, it is the fourth-largest moon in the Solar System. With over 400 active volcanoes , it is also the most geologically active object in the Solar System. Its surface is dotted with over 100 mountains, some of which are taller than Earth’s Mount Everest.

Unlike most satellites in the outer Solar System (which are covered with ice), Io is mainly composed of silicate rock surrounding a molten iron or iron sulfide core. Io has an extremely thin atmosphere made up mostly of sulfur dioxide (SO2). The second innermost Galilean moon is Europa , which takes its name from the mythical Phoenician noblewoman who was courted by Zeus and became the queen of Crete. At 3121.6 kilometers in diameter, it is the smallest of the Galileans, and slightly smaller than the Moon. Europa’s surface consists of a layer of water surrounding the mantle which is thought to be 100 kilometers thick. The uppermost section is solid ice while the bottom is believed to be liquid water, which is made warm due to heat energy and tidal flexing. If true, then it is possible that extraterrestrial life could exist within this subsurface ocean, perhaps near a series of deep-ocean hydrothermal vents . The surface of Europa is also one of the smoothest in the Solar System, a fact which supports the idea of liquid water existing beneath the surface. The lack of craters on the surface is attributed to the surface being young and tectonically active.

Europa is primarily made of silicate rock and likely has an iron core, and a tenuous atmosphere composed primarily of oxygen. Next up is Ganymede . At 5262.4 kilometers in diameter, Ganymede is the largest moon in the Solar System. While it is larger than the planet Mercury, the fact that it is an icy world means that it has only half of Mercury’s mass. It is also the only satellite in the Solar System known to possess a magnetosphere, likely created through convection within the liquid iron core. Ganymede is composed primarily of silicate rock and water ice, and a salt-water ocean is believed to exist nearly 200 km below Ganymede’s surface – though Europa remains the most likely candidate for this. Ganymede has a high number of craters, most of which are now covered in ice, and boasts a thin oxygen atmosphere that includes O, O2, and possibly O3 (ozone), and some atomic hydrogen. Callisto is the fourth and farthest Galilean moon. At 4820.6 kilometers in diameter, it is also the second largest of the Galileans and third largest moon in the Solar System.

Callisto is named after the daughter of the Arkadian King, Lykaon, and a hunting companion of the goddess Artemis. Composed of approximately equal amounts of rock and ices, it is the least dense of the Galileans, and investigations have revealed that Callisto may also have an interior ocean at depths greater than 100 kilometers from the surface. Callisto is also one of the most heavily cratered satellites in the Solar System – the greatest of which is the 3000 km wide basin known as Valhalla. It is surrounded by an extremely thin atmosphere composed of carbon dioxide and probably molecular oxygen. Callisto has long been considered the most suitable place for a human base for future exploration of the Jupiter system since it is furthest from the intense radiation of Jupiter. This natural color view of Ganymede was taken from the Galileo spacecraft during its first encounter with the Jovian moon. Credit: NASA/JPL The Inner Group (or Amalthea group) are four small moons that have diameters of less than 200 km, orbit at radii less than 200,000 km, and have orbital inclinations of less than half a degree.

This groups includes the moons of Metis, Adrastea, Amalthea, and Thebe. Along with a number of as-yet-unseen inner moonlets, these moons replenish and maintain Jupiter’s faint ring system – Metis and Adrastea helping Jupiter’s main ring, while Amalthea and Thebe maintain their own faint outer rings. Metis is the closest moon to Jupiter at a distance of 128,000 km. It is roughly 40 km in diameter, tidally-locked, and highly-asymmetrical in shape (with one of the diameters being almost twice as large as the smallest one). It was not discovered until the 1979 flyby of Jupiter by the Voyager 1 space probe. It was named in 1983 after the first wife of Zeus. The second closest moon is Adrastea , which is about 129,000 km from Jupiter and 20 km in diameter. Also known as Jupiter XV, Amalthea is the second by distance, and the smallest of the four inner moons of Jupiter.

It was discovered in 1979 when the Voyager 2 probe photographed it during a flyby. A schema of Jupiter’s ring system showing the four main components. For simplicity, Metis and Adrastea are depicted as sharing their orbit. Credit: NASA/JPL/Cornell University Amalthea , also known as Jupiter V, is the third moon of Jupiter in order of distance from the planet. It was discovered on September 9, 1892, by Edward Emerson Barnard and named after a nymph in Greek mythology. It is thought to consist of porous water ice with unknown amounts of other materials. Its surface features include large craters and ridges. Thebe (aka. Jupiter XIV) is the fourth and final inner moon of Jupiter. It is irregularly shaped and reddish in colour, and is thought like Amalthea to consist of porous water ice with unknown amounts of other materials. Its surface features also include large craters and high mountains – some of which are comparable to the size of the moon itself. Irregular Satellites: The Irregular Satellites are those that are substantially smaller and have more distant and eccentric orbits than the Regular Satellites.

These moons are broken down into families that have similarities in orbit and composition. It is believed that these were at least partially formed as a result of collisions, most likely by asteroids that were captured by Jupiter’s gravitational field. Amalthea, as photographed by the Galileo spacecraft. The left is from August 12, 1999 at a range of 446,000 km, the right from November 26, 1999 at a range of 374,000. Credit: NASA/JPL Those that are grouped into families are all named after their largest member. For example, the Himalia group is named after Himalia – a satellite with a mean radius of 85 km, making it the fifth largest moon orbiting Jupiter. It is believed that Himalia was once an asteroid that was captured by Jupiter’s gravity, which then experienced a impact that formed the moons of Leda, Lysithea, and Elara. These moons all have prograde orbits, meaning they orbit in the same direction as Jupiter’s rotation. The Carme group takes its name from the Moon of the same name.

With a mean radius of 23 km, Carme is the largest member of a family of Jovian satellites which have similar orbits and appearance (uniformly red), and are therefore thought to have a common origin. The satellites in this family all have retrograde orbits, meaning they orbit Jupiter in the opposite direction of its rotation. The Ananke group is named after its largest satellite, which has a mean radius of 14 km. It is believed that Ananke was also an asteroid that was captured by Jupiter’s gravity and then suffered a collision which broke off a number of pieces. Those pieces became the other 15 moons in the Ananke group, all of which have retrograde orbits and appear gray in color. This image shows the Themis Main Belt which sits between Mars and Jupiter. Credit: Josh Emery/University of Tennessee, Knoxville The Pasiphae group is a very diverse group which ranges in color from red to grey – signifying the possibility of it being the result of multiple collisions. Named after Paisphae , which has a mean radius of 30 km, these satellites are retrograde, and are also believed to be the result of an asteroid that was captured by Jupiter and fragmented due to a series of collisions.

There are also several irregular satellites that are not part of any particular family. These include Themisto and Carpo , the innermost and outermost irregular moons, both of which have prograde orbits. S/2003 J 12 and S/2011 J 1 are the innermost of the retrograde moons, while S/2003 J 2 is the outermost moon of Jupiter. Structure and Composition: As a rule, the mean density of Jupiter’s moons decrease with their distance from the planet. Callisto, the least dense of the four, has an intermediate density between ice and rock, whereas Io has a density that indicates its made of rock and iron. Callisto’s surface also has a heavily cratered ice surface, and the way it rotates indicates that its density is equally distributed. This suggests that Callisto has no rocky or metallic core, but consists of a homogeneous mix of ice and rock. The rotation of the three inner moons, in contrast, indicates differentiation between a core of denser matter (such as silicates, rock and metals) and a mantle of lighter material (water ice). Surface features of the four members at different levels of zoom in each row.

Credit: NASA/JPL The distance from Jupiter also accords with significant alterations in the surface structure of its moons. Ganymede reveals past tectonic movement of the ice surface, which would mean that the subsurface layers underwent partial melting at once time. Europa reveals more dynamic and recent movement of this nature, suggesting a thinner ice crust. Finally, Io, the innermost moon, has a sulfur surface, active volcanism, and no sign of ice. All this evidence suggests that the nearer a moon is to Jupiter, the hotter its interior – with models suggesting that the level of tidal heating is in inverse proportion to the square of their distance from the planet. It is believed that all of Jupiter’s moons may have once had an internal composition similar to that of modern-day Callisto, while the rest changed over time as a result of tidal heating caused by Jupiter’s gravitational field. What this means is that for all of Jupiter’s moons, except Callisto, their interior ice melted, allowing rock and iron to sink to the interior and water to cover the surface. In Ganymede, a thick and solid ice crust then formed while in warmer Europa, a thinner more easily broken crust formed.

On Io, the closest planet to Jupiter, the heating was so extreme that all the rock melted and the water boiled out into space. Jupiter, a gas giant of immense proportions, was appropriately named after the king of the Roman pantheon. It is only befitting that such a planet has many, many moons orbiting it. Given the discovery process, and how long it has taken us, it would not be surprising if there are more satellites around Jupiter just waiting to be discovered. Sixty-seven and counting! Moons Moons: Moons are `fossils" into a planet's past.

The major, named moon systems are: Earth: Luna (The Moon) Mars: Deimos, Phobos Jupiter: Adrastea, Amalthea, Ananke, Callisto, Carme, Elara, Europa, Ganymede, Himalia, Io, Leda, Lysithea, Metis, Pasiphae, Sinope, Thebe Saturn: Atlas, Calypso, Dione, Enceladus, Epimetheus, Helene, Hyperion, Iapetus, Janus, Mimas, Pan, Pandora, Phoebe, Prometheus, Rhea, Telesto, Tethys, Titan Uranus: Ariel, Belinda, Bianca, Cordelia, Cressida, Desdemona, Juliet, Miranda, Oberon, Ophelia, Portia, Puck, Rosalind, Titania, Umbriel Neptune: Despina, Galatea, Larissa, Naiad, Nereid, Proteus, Thalassa, Triton Pluto: Charon (note: Pluto/Charon form a binary system, but Charon is the smaller so it is classed as the moon of Pluto) New, smaller moons are being discovered all the

 time with recent space missions.

The total count of moons (as of 12/18/2001) are: Mercury - 0 moons Mars - 2 moons Uranus - 20 moons Venus - 0 moons Jupiter - 28 moons Neptune - 8 moons Earth - 1 moon Saturn - 30 moons Pluto - 1 moon Moons range in shape from highly irregular to spheres. Their shape reflects their formation history, irregular objects are ill-formed moons (captured asteroids or comets) or pieces of a larger moon, spherical objects were once molten spheres, probably at the time of their formation. Moons of Mars: Deimos & Phobos We speculate, from their irregular appearances and low mean densities, that Deimos and Phobos, are captured asteroids. Both Deimos and Phobos are saturated with craters. Deimos has a smoother appearance caused by partial filling of some of its craters. Moons of Jupiter: Jupiter has 63 confirmed moons as of Jan 2009, i.e. moons with known orbits around Jupiter. Eight of these moons are regular, meaning they have prograde, nearly circular orbits.

They are composed of the four Galilean satellites, plus the inner or Amalthea group: Adrastea is a typical small moon Metis is the innermost known satellite of Jupiter Amalthea is one of Jupiter's smaller, irregular moons, an example of moon collecting dust from another moon (Io) The remaining 55 moons are irregular, they have a mixture of prograde and retrograde orbits with high inclinations and eccentricities. Jupiter's regular satellites are believed to have formed from a circumplanetary disk, a ring of accreting gas and solid debris analogous to a protoplanetary disk. The irregular satellites are substantially smaller objects with more distant and eccentric orbits. They form families with shared similarities in orbit (semi-major axis, inclination, eccentricity) and composition; it is believed that these are at least partially collisional families that were created when larger (but still small) parent bodies were shattered by impacts from asteroids captured by Jupiter's gravitational field. Moons of Saturn: The moons of Saturn are numerous and diverse, ranging from tiny moonlets less than 1 kilometer across to the enormous Titan, which is larger than the planet Mercury.

Saturn has sixty-two moons with confirmed orbits, fifty-three of which have names, and only thirteen of which have diameters larger than 50 kilometers. Saturn has seven moons that are large enough to become spherical. Twenty-four of Saturn's moons are regular satellites; they have prograde orbits not greatly inclined to the Saturn's equatorial plane. These include the seven major satellites, four small moons which exist in a Trojan orbit with larger moons, two mutually co-orbital moons and two moons which act as shepherds of Saturn's F Ring. Two other known regular satellites orbit within gaps in Saturn's rings. The relatively large Hyperion is locked in a resonance with Titan. The remaining regular moons orbit near the outer edge of the A Ring, within G Ring and between the major moons Mimas and Enceladus. The regular satellites are traditionally named after Titans and Titanesses or other figures associated with the mythological Saturn. The remaining thirty-eight, all small except one, are irregular satellites, whose orbits are much farther from Saturn, have high inclinations, and are mixed between prograde and retrograde. These moons are probably captured minor planets, or debris from the breakup of such bodies after they were captured, creating collisional families.

The irregular satellites have been classified by their orbital characteristics into the Inuit, Norse, and Gallic groups, and their names are chosen from the corresponding mythologies. The largest of the irregular moons is Phoebe, the ninth moon of Saturn, discovered at the end of the 19th century. The rings of Saturn are made up of objects ranging in size from microscopic to hundreds of meters, each of which is on its own orbit about the planet. Thus, a precise number of Saturnian moons cannot be given, as there is no objective boundary between the countless small anonymous objects that form Saturn's ring system and the larger objects that have been named as moons. At least 150 moonlets embedded in the rings have been detected by the disturbance they create in the surrounding ring material, though this is thought to be only a small sample of the total population of such objects. Daphnis drifts through the Keeler gap Atlas the second of Saturn's known satellites, orbits near the outer edge of the A-ring Enceladus is one of the innermost moons of Saturn.

Enceladus reflects almost 100 percent of the sunlight that strikes it and has evidence of internal heating and recent resurfacing effects Hyperion is one of the smaller moons of Saturn. It has a pock-marked body and is the largest irregularly shaped satellite ever observed.

Iapetus is one of the stranger moons of Saturn, its leading side is dark with a slight reddish color while its trailing side is bright Dione is the densest moon of Saturn other than Titan, and has several usual characteristics: 1) has a rocky core and ice crust, 2) is heavy cratering on trailing hemisphere, 3) has bright, wispy features Rhea is the largest airless satellite of Saturn that has different regions with different crater sizes indicating that parts of the moon have undergone resurfacing since formation Mimas is one of the innermost moons of Saturn with a very large impact crater that came close to fracturing the moon Tethys is an icy body similar in nature to Dione and Rhea Phoebe is the last of the known satellites of Saturn and orbits in a retrograde direction (opposite to the direction of the other satellites' orbits) in a plane much closer to the ecliptic than to Saturn's equatorial plane. Thus, Phoebe may be a captured asteroid with a composition unmodified since the time it was formed in the outer Solar System.

Moons of Uranus: Uranus, the seventh planet of the Solar System, has 27 known moons, all of which are named after characters from the works of William Shakespeare and Alexander Pope. William Herschel discovered the first two moons, Titania and Oberon, in 1787, and the other spherical moons were discovered in 1851 by William Lassell (Ariel and Umbriel) and in 1948 by Gerard Kuiper (Miranda). The remaining moons were discovered after 1985, either during the Voyager 2 flyby mission or with the aid of advanced Earth-based telescopes. A montage of Uranus' large moons and one smaller moon: from left to right Puck, Miranda, Ariel, Umbriel, Titania and Oberon. Uranian moons are divided into three groups: thirteen inner moons, five major moons, and nine irregular moons. The inner moons are small dark bodies that share common properties and origins with the planet's rings. The five major moons are massive enough to have achieved hydrostatic equilibrium (they were once molten spheres), and four of them show signs of internally driven processes such as canyon formation and volcanism on their surfaces.

The largest of these five, Titania, is 1,578 km in diameter and the eighth-largest moon in the Solar System, and about 20 times less massive than Earth's Moon. Uranus's irregular moons have elliptical and strongly inclined (mostly retrograde) orbits at great distances from the planet. Ariel is a relatively small satellite and is the brightest moon of Uranus Miranda with a jumbled surface unlike anything in the Solar System, indicates evidence of violent past with possible multiple shattering and reassembly Titania is the largest moon of Uranus and is marked by a few large impact basins Moons of Neptune: Neptune has thirteen known moons, by far the largest of which is Triton, discovered by William Lassell just 17 days after the discovery of Neptune itself. Over a century passed before the discovery of the second natural satellite, called Nereid. Neptune's moons are named for minor water deities in Greek mythology. Unique among all large planetary moons, Triton is an irregular satellite, as its orbit is retrograde to Neptune's rotation and inclined relative to the planet's equator.

The next-largest irregular satellite in the Solar System, Saturn's moon Phoebe, is only 0.03% Triton's mass. Triton is massive enough to have achieved hydrostatic equilibrium and to retain a thin atmosphere capable of forming clouds and hazes. Both its atmosphere and its surface are composed mainly of nitrogen with small amounts of methane and carbon monoxide. Triton's surface appears relatively young, and was probably modified by internally driven processes within the last few million years. The temperature at its surface is about 38K. Inward of Triton are six regular satellites, all of which have prograde orbits in planes that lie close to Neptune's equatorial plane. Some of these orbit among Neptune's rings. The largest of them is Proteus. Neptune also has six outer irregular satellites, including Nereid, whose orbits are much farther from Neptune, have high inclinations, and are mixed between prograde and retrograde. The two outermost ones, Psamathe and Neso, have the largest orbits of any natural satellites discovered in the Solar System to date. Proteus is one of the darkest objects in the Solar System What are the names of the satellites orbiting Jupiter?

| Reference.com What are the names of the satellites orbiting Jupiter? A: Quick Answer Galileo Galilei made a significant contribution to science when he discovered four satellites of Jupiter. These moons were first observed as of January 1610, and were originally named the “Medicean planets.” Full Answer Each of the individual moons were numerically numbered as I, II, III and IV, this naming system was used for over two hundred years. As of the mid 1800s the Galilean moons adopted the names Callisto, Ganymede, Europa and Io. It became apparent that the number system would be confusing with the discovery of all the additional new moons. As of January 2011, the planet Jupiter has 50 officially named satellites. There are 13 other moons proposed for the planet based on various observations; these discoveries have not yet been named nor confirmed.

The 50 satellites on Jupiter include: Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede, Callisto, Themisto, Leda, Himalia, Lysithea, Elara, Carpo, Euporie, Orthosie, Euanthe, Thyone, Mneme, Harpalyke, Hermippe, Praxidike, Thelxinoe, Iocaste, Ananke, Arche, Pasithee, Herse, Chaldene, Kale, Isonoe, Aitne, Erinome, Taygete, Carme, Kalyke, Eukelade, Kallichore, Helike, Eurydome, Autonoe, Sponde, Pasiphae, Megaclite, Sinope, Hegemone, Aoede, Callirrhoe, Cyllene, Kore. After Galileo Galilei made this great contribution to science, Copernicus dismissed the earth-centric theory in favor of the helio-centric theory. Jupiter's satellites | Article about Jupiter's satellites by The Free Dictionary Jupiter's satellites | Article about Jupiter's satellites by The Free Dictionary Also found in: Wikipedia .

Jupiter's satellites (Jovian satellites) A system of diverse satellites orbiting Jupiter at distances between 128 000 km and 24 million km and ranging in size from the planet-like Galilean satellites to tiny worlds of rock and ice measuring barely 1 kilometer across. At the end of 2004, 63 Jovian satellites were known, most of which were discovered after 2000 through analysis of photographs taken either by spacecraft such as the Voyager probes or Galileo mission or by high-quality groundbased instruments using large-format CCDs. Their physical and orbital properties are given in Table 2, backmatter. The satellites can be divided into three main groups. The largest is an outer group of at least 48 small bodies moving in loosely bound retrograde orbits (see direct motion ) that are highly eccentric and are inclined to Jupiter's equatorial plane by an angle of about 150°–160°; most of them orbit the planet in periods of about 700 days and at mean distances of roughly 21 to 24 million km. Chief among them are Ananke, Carme, Pasiphae, and Sinope.

The most remote one of this group so far known, designated S/2003 J2, in fact orbits Jupiter in more than 900 days at a mean distance of more than 28 million km. An intermediate group of five small satellites (Leda, Himalia, Lysithea, Elara, and S/2000 J11) move in approximately 250-day direct orbits at mean orbital distances between 11 and 12 million km; the orbits are generally less eccentric than those of the outer group and are inclined at an angle of about 28° to Jupiter's equatorial plane. Two other satellites follow direct orbits that do not fit neatly into either the outer or intermediate groups. These are Themisto, which orbits Jupiter in 130 days at a mean distance of about 7 million km and with an inclination of 43°, and S/2003 J20, which completes an orbit every 456 days at a mean distance of 17 million km and an inclination of 51°.

The inner group is comprised of the four large Galilean satellites – Io , Europa , Ganymede , and Callisto – together with Amalthea and the three satellites Thebe, Adrastea, and Metis; these all move in near-circular direct orbits that lie close to the plane of Jupiter's equator. The members of the outer and intermediate groups are probably captured asteroids , although the capturing process that would place objects into one group rather than the other has not been defined. Possibly some of them were former members of the Trojan group of asteroids. All eight inner satellites are believed to have formed out of the dust particles that surrounded the disk of gas and dust from which Jupiter formed. These inner satellites all lie within Jupiter's magnetosphere and are effective in sweeping up the charged particles found there, becoming intensely radioactive in the process. Metis, Jupiter's innermost satellite, was unknown before Voyager 2 photographed it in 1979. So too were Thebe and Adrastea. The irregularly shaped Amalthea had been discovered in 1892, but few details of it were known before the visit of the Voyager probes.

The Galilean satellites, however, have been studied throughout the telescopic era but came under much more intensive scrutiny from Pioneer 10 and 11, as well as the Voyager and Galileo missions. Metis | The Solar System Wiki | Fandom powered by Wikia THE SOLAR SYSTEM WIKI Alternate Name(s) Jupiter XVI Metis, also known as Jupiter XVI, is the innermost irregular-shaped satellite belonging to the outer planet of Jupiter . It is one of the three satellites known in the Solar System to orbit its home planet in less time than its home planet's day, the other being Adrastea , another satellite belonging to Jupiter, and Mars ' largest moon, Phobos . This satellite was discovered by Stephen P. Synnott on March 4, 1979. Orbit Edit Metis orbits in the inner regions of Jupiter's main ring and is one of the planets in the Solar System to orbit its home planet in less time than its home planet's day. Tidal forces, which is a gravitational pull on a planet caused by a satellite's inner ocean, keep this planet in a constant orbit around Jupiter.

Since this pull is so strong, however, Metis is predicted to collide with Jupiter in the next few million years. Metis is one of the three moons in the Solar System that orbit its home planet in less time than the planet's day. The others are another one of Jupiter's satellites, Adrastea , and Mars' largest satellite, Phobos . JUPITER'S Moons - EnchantedLearning.com Jupiter's Moons Activities, Web Links JUPITER'S MOONS Jupiter has four large moons and dozens of smaller ones (there are about 67 known moons so far). Galileo first discovered the four largest moons of Jupiter, Io, Europa, Ganymede, and Callisto in 1610, using a 20-power telescope; these moons are known as the Galilean moons.

The moons of Jupiter are (in order by their distance from Jupiter): Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede (the biggest), Callisto (the second biggest), Leda (the smallest), Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae, Sinope, and many newly-discovered moons that haven't been named yet. METIS Metis is the closest moon to Jupiter. Metis is 25 miles (40 km) in diameter and orbits 79,500 miles (128,000 km) from Jupiter, within its main ring. Metis and the next moon, Adrastea, are probably the source of the dust in this ring. Metis has a mass of 9 x 1016kg. It orbits Jupiter in 0.294780 (Earth) days; this is faster than Jupiter rotates on its axis. Metis was discovered by Stephen Synnott (Voyager 2) in 1980. ADRASTEA Adrastea is the second-closest moon to Jupiter.

Adrastea is 12 miles (20 km) in diameter and orbits 80,000 miles (129,000 km) from Jupiter, within its main ring. Adrastea and the first moon, Metis, are probably the source of the dust in this ring. Adrastea has a mass of 1.91 x 1016kg. It orbits Jupiter in 0.29826 (Earth) days; this is faster than Jupiter rotates on its axis. Adrastea was discovered by D. Jewitt and E. Danielson (Voyager 2) in 1979. AMALTHEA Amalthea is the third-closest moon to Jupiter and the reddest object in our solar system . Amalthea is 145 x 91 x 83 miles (232 x146 x134 km) in diameter and orbits 112,700 miles (181,300 km) from Jupiter, within the faint Gossamer ring. Amalthea and Thebe likely provide the dust for the Gossamer ring.

Amalthea has a mass of 7.2 x 1021kg. It orbits Jupiter in 0.49817905 (Earth) days and is in synchronous rotation (always keeping the same side facing Jupiter). Amalthea gives off more heat than it receives from the Sun. Amalthea was discovered by Edward Emerson Barnard in 1892. THEBE Thebe is the fourth-closest moon to Jupiter. Thebe is 68 x 56 miles (110 x 90 km) in diameter and orbits 138,000 miles (222,000 km) from Jupiter. Amalthea and Thebe likely provide the dust for the Gossamer ring. Thebe has a mass of 8 x 1017kg. It orbits Jupiter in 0.6745 day (Earth) days and is in synchronous rotation (always keeping the same side facing Jupiter). Thebe was discovered by Stephen Synnott (Voyager 1) in 1980. THE GALILEAN MOONS Two sulfurous eruptions on Io.

Pillan Patera, a volcanic caldera at the left, spews sulfur 86 miles above the surface. IO Io is a large, rocky, volcanically active moon of Jupiter. Its volcanoes spew out molten sulfur, making Io a very colorful moon. It is the innermost of Jupiter's four large moons and the third largest. It has a diameter of 1,942 miles (3,636 km), very close in size to our moon . Io's mean distance from Jupiter is 220,000 miles (422,000 km). It has a mass of 8.93x1022 kg. It takes Io 1.77 days to orbit Jupiter. There is a doughnut-shaped plasma cloud around Jupiter near Io's orbit (known as the "Io plasma torus") This torus is caused by Jupiter's strong magnetic field, which strips ions from Io as it rotates; Io acts like an electrical generator. Io was discovered by Galileo and Marius (independently) in 1610.

Ole Romer (1644-1710) was a Danish astronomer who, in 1675-1676, was the first person to demonstrate that the speed of light is finite. Romer did this by observing eclipses of Jupiter's moon Io as Jupiter's distance from Earth varied through the year. He noticed that the observed period of Io's orbit differed by about 20 minutes; he concluded that this difference was due to the extra distance that the light had to travel to Earth. His calculations put the speed of light at about 225,000 kilometers per second (it is really a bit faster, at 299,792 kilometers per second). EUROPA Europa is a large, dense, icy moon of Jupiter. Europa is the smoothest object in our Solar System . Its surface is covered with long, crisscrossing trackways (but few craters) on water ice. Frozen sulfuric acid has been found on its surface. Europa's diameter is less than 2,000 miles (3,138 km), smaller than the Earth's moon .

It takes Europa 3.55 days to orbit Jupiter (in a synchronous orbit). Its mean distance from Jupiter is about 420,000 miles (670,900 km). Its mass is 4.80x1022 kg. It was discovered by Galileo and S. Marius (independently) in 1610. GANYMEDE Ganymede is the largest moon of Jupiter, a large, icy, outer moon that is scarred with impact craters and many parallel faults. It has a diameter of about 3,400 miles (5,268 km) and orbits Jupiter at a mean distance of 664,000 miles (1,070,000 km). It has a magnetic field and probably has a molten iron core. It takes Ganymede 171.75 hours (7.15 Earth days) to orbit Jupiter. Its mass is 1.48x1023 kg. It was discovered by Galileo and S. Marius (independently) in 1610.

Ganymede is the largest moon in the solar system; it is also larger than the planets Mercury and Pluto. CALLISTO Callisto is a large, icy, dark-colored, low-density outer moon of Jupiter that is scarred with impact craters and ejecta. It has a diameter of about 3,000 miles (4800 km), the second-largest moon of Jupiter; it is roughly the size of Mercury . Callisto has the largest-known impact crater in the Solar System, Valhalla, which has a bright patch 600 km across and rings that go out to almost 3000 km. Callisto orbits Jupiter at a mean distance of 1,170,000 miles (1,883,000 km). Its mass is 1.08x1023 kg. It takes Callisto 400.8 hours = 16.7 days to orbit Jupiter (in a synchronous orbit). Callisto was discovered by Galileo and S. Marius (independently) in 1610. LEDA Leda is Jupiter's ninth and smallest moon.

Leda is 9.9 miles (16 km km) in diameter and orbits at an average of 6,900,000 miles (11,094,000 km) from Jupiter. Leda has a mass of 5.68 x 1015kg. It orbits Jupiter in 238.72 (Earth) days. Very little is known about Leda. Leda was discovered by Charles Kowal in 1974. HIMALIA Himalia is Jupiter's tenth moon. Himalia is 110 miles (170 km) in diameter and orbits 7,000,000 miles (11,480,000 km) from Jupiter. Himalia has a mass of 9.5 x 1018kg. It orbits Jupiter in 250.5662 (Earth) days. Very little is known about Himalia. Himalia was discovered by C. Perrine in 1904. LYSITHEA Lysithea is Jupiter's eleventh moon.

Lysithea is 15 miles (24 km) in diameter and orbits 7,200,000 miles (11,720,000 km) from Jupiter. Lysithea has a mass of 8 x 1016kg. It orbits Jupiter in 259.22 (Earth) days. Very little is known about Lysithea. Lysithea was discovered by S. Nicholson in 1938. ELARA Elara is Jupiter's twelfth moon. Elara is 50 miles (80 km) in diameter and orbits 7,250,000 miles (11,737,000 km) from Jupiter. Elara has a mass of 8 x 1017kg. It orbits Jupiter in 259.6528 (Earth) days. Very little is known about Elara. Elara was discovered by C. Perrine in 1905. ANANKE Ananke is Jupiter's thirteenth moon.

Ananke is 12.5 miles (20 km) in diameter and orbits 13,100,000 miles (21,200,000 km) from Jupiter. Ananke has a mass of 4 x 1016kg. It orbits Jupiter in 631 (Earth) days and is in a retrograde orbit (orbiting opposite to the direction of Jupiter). Very little is known about Ananke. Ananke was discovered by S. Nicholson in 1951. CARME Carme is Jupiter's fourteenth moon. Carme is 18.5 miles (30 km) in diameter and orbits 13,800,000 miles (22,600,000 km) from Jupiter. Carme has a mass of 9 x 1016kg. It orbits Jupiter in 692 (Earth) days and is in a retrograde orbit (orbiting opposite to the direction of Jupiter). Very little is known about Carme. Carme was discovered by S. Nicholson in 1938. PASIPHAE Pasiphae is Jupiter's fifteenth moon.

Pasiphae is 22 miles (36 km) in diameter and orbits 14,600,000 miles (23,500,000 km) from Jupiter. Pasiphae has a mass of 2 x 1023kg. It orbits Jupiter in 735 (Earth) days and is in a retrograde orbit (orbiting opposite to the direction of Jupiter). Very little is known about Pasiphae. Pasiphae was discovered by P. Melotte in 1908. SINOPE Sinope is Jupiter's sixteenth moon. Sinope is 17.5 miles (28 km) in diameter and orbits 14,700,000 miles (23,700,000 km) from Jupiter. Sinope has a mass of 8 x 1016kg. It orbits Jupiter in 758 (Earth) days and is in a retrograde orbit (orbiting opposite to the direction of Jupiter). Very little is known about Sinope. Sinope was discovered by S. Nicholson in 1914.

S/1999 J 1 (a provisional name) The seventeenth and outermost moon; S/1999 J 1 is the smallest-known moon orbiting a major planet. This moon is 3 miles (5 km) in diameter and has an irregular orbit roughly 15 million miles (24 million km) from Jupiter. It orbits Jupiter in 774 (Earth) days and is in a retrograde orbit (orbiting opposite to the direction of Jupiter). It was discovered by Robert S. McMillan et al (at the Spacewatch program at the University of Arizona ) in 2000.

Question: 'Metis', 'Callisto', and 'Sinope' are three of the satellites of which planet?
Answer: JUPITER