Europa (moon)

Europa
True color image taken by the Galileo probe
Europa's trailing hemisphere, as seen by the Galileo spacecraft. The prominent crater in the lower right is Pwyll. Darker regions are areas where Europa's primarily water ice surface has a higher mineral content.
Discovery
Discovered by Galilei, Galileo
Marius, Simon
Discovery date January 7, 1610[1]
Designations
Alternate name(s) Jupiter II
Adjective Europan
Epoch January 8, 2004
Periapsis 664 862 km[3]
Apoapsis 676 938 km[3]
Mean orbit radius 670 900 km[4]
Eccentricity 0.009[4]
Orbital period 3.551 181 d[4]
Average orbital speed 13.740 km/s[4]
Inclination 0.470° (to Jupiter's equator)[4]
Satellite of Jupiter
Physical characteristics
Mean radius 1569 km (0.245 Earths)[4]
Surface area 3.09 × 107 km2 (0.061 Earths)[5]
Volume 1.593 × 1010 km3 (0.015 Earths)[5]
Mass 4.80 × 1022 kg (0.008 Earths)[4]
Mean density 3.01 g/cm3[4]
Equatorial surface gravity 1.314 m/s2 (0.134 g)[3]
Escape velocity 2.025 km/s[3]
Rotation period Synchronous[6]
Axial tilt 0.1°[7]
Albedo 0.67 ± 0.03[8]
Surface temp.
   Surface
min mean max
~50 K[9] 102 K 125 K
Apparent magnitude 5.29 (opposition)[8]
Atmosphere
Surface pressure 0.1 µPa (10-12 bar)[10]

Europa (pronounced /jʊˈroʊpə/ ( listen);[11] or as Greek Ευρώπη) is the sixth moon of the planet Jupiter, and the smallest of its four Galilean satellites. Europa was discovered in 1610 by Galileo Galilei (and possibly independently by Simon Marius), and named after a mythical Phoenician noblewoman, Europa, who was courted by Zeus and became the queen of Crete.

Roughly the size of Earth's Moon, Europa is primarily made of silicate rock and probably has an iron core. It has a tenuous atmosphere composed primarily of oxygen. Its surface is composed of ice and is one of the smoothest in the Solar System. This surface is striated by cracks and streaks, while craters are relatively infrequent. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it, which could conceivably serve as an abode for extraterrestrial life.[12] This hypothesis proposes that heat energy from tidal flexing causes the ocean to remain liquid and drives geological activity similar to plate tectonics.[13]

Although only fly-by missions have visited the moon, the intriguing characteristics of Europa have led to several ambitious exploration proposals. The Galileo mission provided the bulk of current data on Europa. A new mission to Jupiter's icy moons, the Europa Jupiter System Mission (EJSM), is proposed for a launch in 2020.[14] Conjecture on extraterrestrial life has ensured a high profile for the moon and has led to steady lobbying for future missions.[15][16]

Contents

Discovery and naming

Europa, along with Jupiter's three other largest moons, Io, Ganymede, and Callisto, was discovered by Galileo Galilei in January 1610. The first reported observation of Io was made by Galileo Galilei on January 7, 1610 using a 20x-power, refracting telescope at the University of Padua. However, in that observation, Galileo could not separate Io and Europa due to the low power of his telescope, so the two were recorded as a single point of light. Io and Europa were seen for the first time as separate bodies during Galileo's observations of the Jupiter system the following day, January 8, 1610 (used as the discovery date for Europa by the IAU).[1]

Like all the Galilean satellites, Europa is named after a lover of Zeus, the Greek counterpart of Jupiter, in this case Europa, daughter of the king of Tyre. The naming scheme was suggested by Simon Marius, who apparently discovered the four satellites independently, though Galileo alleged that Marius had plagiarized him. Marius attributed the proposal to Johannes Kepler.[17][18]

The names fell out of favor for a considerable time and were not revived in general use until the mid-20th century.[19] In much of the earlier astronomical literature, Europa is simply referred to by its Roman numeral designation as Jupiter II (a system introduced by Galileo) or as the "second satellite of Jupiter". In 1892, the discovery of Amalthea, whose orbit lay closer to Jupiter than those of the Galilean moons, pushed Europa to the third position. The Voyager probes discovered three more inner satellites in 1979, so Europa is now considered Jupiter's sixth satellite, though it is still sometimes referred to as Jupiter II.[19]

Orbit and rotation

Animation showing Io's Laplace resonance with Europa and Ganymede

Europa orbits Jupiter in just over three and a half days, with an orbital radius of about 670,900 km. With an eccentricity of only 0.009, the orbit itself is nearly circular, and the orbital inclination relative to the Jovian equatorial plane is small, at 0.470°.[20] Like its fellow Galilean satellites, Europa is tidally locked to Jupiter, with one hemisphere of the satellite constantly facing the planet. Europa's prime meridian intersects the north and south poles, and the equator at the sub-Jovian point.[21] Research suggests the tidal locking may not be full, as a non-synchronous rotation has been proposed: Europa spins faster than it orbits, or at least did so in the past. This suggests an asymmetry in internal mass distribution and that a layer of subsurface liquid separates the icy crust from the rocky interior.[22]

The slight eccentricity of Europa's orbit, maintained by the gravitational disturbances from the other Galileans, causes Europa's sub-Jovian point to oscillate about a mean position. As Europa comes slightly nearer to Jupiter, the planet's gravitational attraction increases, causing the moon to elongate towards it. As Europa moves slightly away from Jupiter, the planet's gravitational force decreases, causing the moon to relax back into a more spherical shape. The orbital eccentricity of Europa is continuously pumped by its mean-motion resonance with Io.[23] Thus, the tidal flexing kneads Europa's interior and gives the moon a source of heat, allowing its ocean to stay liquid and driving subsurface geological processes.[13][23] The ultimate source of this energy is Jupiter's rotation, which is tapped by Io through the tides it raises on Jupiter and is transferred to Europa and Ganymede by the orbital resonance.[23][24]

Physical characteristics

Model of Europa's interior showing a solid ice crust over a layer of liquid water or soft ice, a silicate mantle and a metallic core.

Europa is slightly smaller than Earth's Moon. At just over 3,100 kilometres (1,900 mi) in diameter, it is the sixth-largest moon and fifteenth largest object in the Solar System. Though by a wide margin the least massive of the Galilean satellites, it is nonetheless more massive than all known moons in the Solar System smaller than itself combined.[25] Its bulk density suggests that it is similar in composition to the terrestrial planets, being primarily composed of silicate rock.[26]

Internal structure

It is believed that Europa has an outer layer of water around 100 km (62 mi) thick; some as frozen-ice upper crust, some as liquid ocean underneath the ice. Recent magnetic field data from the Galileo orbiter showed that Europa has an induced magnetic field through interaction with Jupiter's, which suggests the presence of a subsurface conductive layer. The layer is likely a salty liquid water ocean. The crust is estimated to have undergone a shift of 80°, nearly flipping over (see true polar wander), which would be unlikely if the ice were solidly attached to the mantle.[27] Europa probably contains a metallic iron core.[28]

Surface features

Mosaic of Galileo images showing features indicative of internal geologic activity: lineae, lenticulae (domes, pits) and Conamara Chaos.

Europa is one of the smoothest objects in the Solar System.[29] The prominent markings crisscrossing the moon seem to be mainly albedo features, which emphasize low topography. There are few craters on Europa because its surface is tectonically active and young.[30][31] Europa's icy crust gives it an albedo (light reflectivity) of 0.64, one of the highest of all moons.[20][31] This would seem to indicate a young and active surface; based on estimates of the frequency of cometary bombardment that Europa probably endures, the surface is about 20 to 180 million years old.[32] There is currently no full scientific consensus among the sometimes contradictory explanations for the surface features of Europa.[33]

The radiation level at the surface of Europa is equivalent to a dose of about 540 rem (5400 mSv) per day,[34] an amount of radiation that would cause illness in human beings.[35]

Lineae

Approximately natural color image of Europa by the Galileo spacecraft, showing lineae

Europa's most striking surface features are a series of dark streaks crisscrossing the entire globe, called lineae (English: lines). Close examination shows that the edges of Europa's crust on either side of the cracks have moved relative to each other. The larger bands are more than 20 km (12 mi) across, often with dark, diffuse outer edges, regular striations, and a central band of lighter material.[36]

The most likely hypothesis states that these lineae may have been produced by a series of eruptions of warm ice as the Europan crust spread open to expose warmer layers beneath.[37] The effect would have been similar to that seen in the Earth's oceanic ridges. These various fractures are thought to have been caused in large part by the tidal stresses exerted by Jupiter. Since Europa is tidally locked to Jupiter, and therefore always maintains the same approximate orientation towards the planet, the stress patterns should form a distinctive and predictable pattern. However, only the youngest of Europa's fractures conform to the predicted pattern; other fractures appear to occur at increasingly different orientations the older they are. This could be explained if Europa's surface rotates slightly faster than its interior, an effect which is possible due to the subsurface ocean mechanically decoupling the moon's surface from its rocky mantle and the effects of Jupiter's gravity tugging on the moon's outer ice crust.[38] Comparisons of Voyager and Galileo spacecraft photos serve to put an upper limit on this hypothetical slippage. The full revolution of the outer rigid shell relative to the interior of Europa occurs over a minimum of 12,000 years.[39]

Other geological features

Enhanced-color view of part of Conamara Chaos, showing ice rafts up to 10 km (6 mi) across. White areas are ejecta rays from the crater Pwyll.
Craggy, 250 m high peaks and smooth plates are jumbled together in a close-up of Conamara Chaos.

Other features present on Europa are circular and elliptical lenticulae (Latin for "freckles"). Many are domes, some are pits and some are smooth, dark spots. Others have a jumbled or rough texture. The dome tops look like pieces of the older plains around them, suggesting that the domes formed when the plains were pushed up from below.[40]

One hypothesis states that these lenticulae were formed by diapirs of warm ice rising up through the colder ice of the outer crust, much like magma chambers in the Earth's crust.[40] The smooth, dark spots could be formed by meltwater released when the warm ice breaks through the surface. The rough, jumbled lenticulae (called regions of "chaos"; for example, Conamara Chaos) would then be formed from many small fragments of crust embedded in hummocky, dark material, appearing like icebergs in a frozen sea.[41]

An alternative hypothesis suggest that lenticulae are actually small areas of chaos and that the claimed pits, spots and domes are artefacts resulting from over-interpretation of early, low-resolution Galileo images. The implication is that the ice is too thin to support the convective diapir model of feature formation. [42] [43]

Subsurface ocean

Most planetary scientists believe that a layer of liquid water exists beneath Europa's surface, kept warm by tidally generated heat.[44] The heating by radioactive decay, which is almost the same as in Earth (per kg of rock), cannot provide necessary heating in Europa because the volume-to-surface ratio is much lower due to the moon's smaller size. Europa's surface temperature averages about 110 K (−160 °C; −260 °F) at the equator and only 50 K (−220 °C; −370 °F) at the poles, keeping Europa's icy crust as hard as granite.[9] The first hints of a subsurface ocean came from theoretical considerations of tidal heating (a consequence of Europa's slightly eccentric orbit and orbital resonance with the other Galilean moons). Galileo imaging team members argue for the existence of a subsurface ocean from analysis of Voyager and Galileo images.[44] The most dramatic example is "chaos terrain", a common feature on Europa's surface that some interpret as a region where the subsurface ocean has melted through the icy crust. This interpretation is extremely controversial. Most geologists who have studied Europa favor what is commonly called the "thick ice" model, in which the ocean has rarely, if ever, directly interacted with the present surface.[45] The different models for the estimation of the ice shell thickness give values between a few kilometers and tens of kilometers.[46]

Two possible models of Europa

The best evidence for the thick ice model is a study of Europa's large craters. The largest impact structures are surrounded by concentric rings and appear to be filled with relatively flat, fresh ice; based on this and on the calculated amount of heat generated by Europan tides, it is predicted that the outer crust of solid ice is approximately 10–30 km (6–19 mi) thick, including a ductile "warm ice" layer, which could mean that the liquid ocean underneath may be about 100 km (60 mi) deep.[32] This leads to a volume of Europa's oceans of 3 × 1018 m3, slightly more than two times the volume of Earth's oceans.

The thin ice model suggests that Europa's ice shell may be only a few kilometers thick. However, most planetary scientists conclude that this model considers only those topmost layers of Europa's crust which behave elastically when affected by Jupiter's tides. One example is flexure analysis, in which the moon's crust is modeled as a plane or sphere weighted and flexed by a heavy load. Models such as this suggest the outer elastic portion of the ice crust could be as thin as 200 metres (660 ft). If the ice shell of Europa is really only a few kilometers thick, this "thin ice" model would mean that regular contact of the liquid interior with the surface could occur through open ridges, causing the formation of areas of chaotic terrain.[46]

In late 2008, it was suggested Jupiter may keep Europa's oceans warm by generating large planetary tidal waves on the moon because of its small but non-zero obliquity. This previously unconsidered kind of tidal force generates so-called Rossby waves that travel quite slowly, at just a few kilometers per day, but can generate significant kinetic energy. For the current axial tilt estimate of 0.1 degree, the resonance from Rossby waves would store 7.3 × 1017 J of kinetic energy, which is two hundred times larger than that of the flow excited by the dominant tidal forces.[47][48] Dissipation of this energy could be the principal heat source of Europa's ocean.

The Galileo orbiter found that Europa has a weak magnetic moment, which is induced by the varying part of the Jovian magnetic field. The field strength at the magnetic equator (about 120 nT) created by this magnetic moment is about one-sixth the strength of Ganymede's field and six times the value of Callisto's.[49] The existence of the induced moment requires a layer of a highly electrically conductive material in the moon's interior. The most plausible candidate for this role is a large subsurface ocean of liquid saltwater.[28] Spectrographic evidence suggests that the dark, reddish streaks and features on Europa's surface may be rich in salts such as magnesium sulfate, deposited by evaporating water that emerged from within.[50] Sulfuric acid hydrate is another possible explanation for the contaminant observed spectroscopically.[51] In either case, since these materials are colorless or white when pure, some other material must also be present to account for the reddish color, and sulfur compounds are suspected.[52]

Atmosphere

Magnetic field around Europa. The red line shows a trajectory of the Galileo spacecraft during a typical flyby (E4 or E14).

Observations with the Goddard High Resolution Spectrograph of the Hubble Space Telescope, first described in 1995, revealed that Europa has a tenuous atmosphere composed mostly of molecular oxygen (O2).[53][54] The surface pressure of Europa's atmosphere is 0.1 μPa, or 10−12 times that of the Earth.[10] In 1997, the Galileo spacecraft confirmed the presence of a tenuous ionosphere (an upper-atmospheric layer of charged particles) around Europa created by solar radiation and energetic particles from Jupiter's magnetosphere,[55][56] providing evidence of an atmosphere.

Unlike the oxygen in Earth's atmosphere, Europa's is not of biological origin. The surface-bounded atmosphere forms through radiolysis, the dissociation of molecules through radiation[57]. Solar ultraviolet radiation and charged particles (ions and electrons) from the Jovian magnetospheric environment collide with Europa's icy surface, splitting water into oxygen and hydrogen constituents. These chemical components are then adsorbed and "sputtered" into the atmosphere. The same radiation also creates collisional ejections of these products from the surface, and the balance of these two processes forms an atmosphere.[58] Molecular oxygen is the densest component of the atmosphere because it has a long lifetime; after returning to the surface, it does not stick (freeze) like a water or hydrogen peroxide molecule but rather desorbs from the surface and starts another ballistic arc. Molecular hydrogen never reaches the surface, as it is light enough to escape Europa's surface gravity.[59][60]

Observations of the surface have revealed that some of the molecular oxygen produced by radiolysis is not ejected from the surface. Because the surface may interact with the subsurface ocean (considering the geological discussion above), this molecular oxygen may make its way to the ocean, where it could aid in biological processes.[61] One estimate suggests that, given the turnover rate inferred from the apparent ~0.5 Gyr maximum age of Europa's surface ice, subduction of radiolytically generated oxidizing species might well lead to oceanic free oxygen concentrations that are comparable to those in terrestrial deep oceans.[62]

The molecular hydrogen that escapes Europa's gravity, along with atomic and molecular oxygen, forms a torus (ring) of gas in the vicinity of Europa's orbit around Jupiter. This "neutral cloud" has been detected by both the Cassini and Galileo spacecraft, and has a greater content (number of atoms and molecules) than the neutral cloud surrounding Jupiter's inner moon Io. Models predict that almost every atom or molecule in Europa's torus is eventually ionized, thus providing a source to Jupiter's magnetospheric plasma. [63]

Potential for extraterrestrial life

A black smoker in the Atlantic Ocean. Driven by geothermal energy, this and other types of hydrothermal vents create chemical disequilibria that can provide energy sources for life.
This giant tube worm colony dwells beside a Pacific Ocean vent. While the worms require oxygen (hence their blood-red color), methanogens and some other microbes in the vent communities do not.

Europa's unlit interior is now considered to be the most likely location for extant extraterrestrial life in the Solar System.[64] Life could exist in its under-ice ocean, perhaps subsisting in an environment similar to Earth's deep-ocean hydrothermal vents or the Antarctic Lake Vostok.[65] Life in such an ocean could possibly be similar to microbial life on Earth in the deep ocean.[66][67] So far, there is no evidence that life exists on Europa, but the likely presence of liquid water has spurred calls to send a probe there.[68]

Until the 1970s, life, at least as the concept is generally understood, was believed to be entirely dependent on energy from the Sun. Plants on Earth's surface capture energy from sunlight to photosynthesize sugars from carbon dioxide and water, releasing oxygen in the process, and are then eaten by oxygen-respiring animals, passing their energy up the food chain. Even life in the deep ocean far below the photic zone was believed to obtain its nourishment either from the organic detritus raining down from the surface, or by eating animals that in turn depend on that stream of nutrients.[69] A world's ability to support life was thus thought to depend on its access to sunlight.

In 1977, during an exploratory dive to the Galapagos Rift in the deep-sea exploration submersible Alvin, scientists discovered colonies of giant tube worms, clams, crustaceans, mussels, and other assorted creatures clustered around undersea volcanic features known as black smokers.[69] These creatures thrive despite having no access to sunlight, and it was soon discovered that they comprise an entirely independent food chain. Instead of plants, the basis for this food chain was a form of bacterium that derived its energy from oxidization of reactive chemicals, such as hydrogen or hydrogen sulfide, that bubbled up from the Earth's interior. This chemosynthesis revolutionized the study of biology by revealing that life need not be sun-dependent; it only requires water and an energy gradient in order to exist. It opened up a new avenue in astrobiology by massively expanding the number of possible extraterrestrial habitats.

While the tube worms and other multicellular eukaryotic organisms around these hydrothermal vents respire oxygen and thus are indirectly dependent on photosynthesis, anaerobic chemosynthetic bacteria and archaea that inhabit these ecosystems provide a possible model for life in Europa's ocean.[62] The energy provided by tidal flexing drives active geological processes within Europa's interior, just as they do to a far more obvious degree on its sister moon Io. While Europa, like the Earth, may possess an internal energy source from radioactive decay, the energy generated by tidal flexing would be several orders of magnitude greater than any radiological source.[70] However, such an energy source could never support an ecosystem as large and diverse as the photosynthesis-based ecosystem on Earth's surface.[71] Life on Europa could exist clustered around hydrothermal vents on the ocean floor, or below the ocean floor, where endoliths are known to inhabit on Earth. Alternatively, it could exist clinging to the lower surface of the moon's ice layer, much like algae and bacteria in Earth's polar regions, or float freely in Europa's ocean.[72] However, if Europa's ocean were too cold, biological processes similar to those known on Earth could not take place. Similarly, if it were too salty, only extreme halophiles could survive in its environment.[72]

In September 2009, planetary scientist Richard Greenberg calculated that cosmic rays impacting on Europa's surface convert the ice into oxidizers, which could then be absorbed into the ocean below as water wells up to fill cracks. Via this process, Greenberg estimates that Europa's ocean could eventually achieve an oxygen concentration greater than that of Earth's oceans within just a few million years. This would enable Europa to support not merely anaerobic microbial life but potentially larger, aerobic organisms such as fish.[73]

In 2006, Robert T. Pappalardo, an assistant professor in the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder said,

We’ve spent quite a bit of time and effort trying to understand if Mars was once a habitable environment. Europa today, probably, is a habitable environment. We need to confirm this … but Europa, potentially, has all the ingredients for life … and not just four billion years ago … but today.[16]

Exploration

Most human knowledge of Europa has been derived from a series of flybys since the 1970s. The sister crafts Pioneer 10 and Pioneer 11 were the first to visit Jupiter, in 1973 and 1974, respectively; the first photos of Jupiter's largest moons produced by the Pioneers were fuzzy and dim.[29] The Voyager flybys followed in 1979, while the Galileo mission orbited Jupiter for eight years beginning in 1995 and provided the most detailed examination of the Galilean moons that is expected until the end of the 2020s.

Various proposals have been made for future missions. The aims of these missions have ranged from examining Europa's chemical composition to searching for extraterrestrial life in its subsurface ocean.[66][74] Any mission to Europa would need to be protected from the high radiation levels sustained by Jupiter.[15] Europa receives about 540 rem of radiation per day.[75]

Spacecraft proposals and cancellations

Artist's concept of the cryobot and hydrobot

Plans to send a probe to study Europa for signs of liquid water and possible life have been plagued by false starts and budget cuts.[76] Proposed for a launch in 2020, the Europa Jupiter System Mission (EJSM) is a joint NASA/ESA proposal for exploration of Jupiter's moons. In February 2009 it was announced that ESA/NASA had given this mission priority ahead of the Titan Saturn System Mission.[77] ESA's contribution will still face funding competition from other ESA projects.[78] EJSM consists of the NASA-led Jupiter Europa Orbiter, the ESA-led Jupiter Ganymede Orbiter, and possibly a JAXA-led Jupiter Magnetospheric Orbiter. Russia has expressed interest in sending a lander to Europa as part of an international flotilla.

Prior to EJSM, the plan for the extremely ambitious Jupiter Icy Moons Orbiter was cancelled in 2005.[15][76] Before that, the Europa Orbiter received a go-ahead in 1999 but was canceled in 2002. Another possible mission, known as the Ice Clipper mission, would have used an impactor similar to the Deep Impact mission—it would make a controlled crash into the surface of Europa, generating a plume of debris which would then be collected by a small spacecraft flying through the plume.[79][80]

More ambitious ideas have been put forward including an impactor in combination with a thermal drill to search for biosignatures that might be frozen in the shallow subsurface[81][82]. Another proposal calls for a large nuclear-powered "melt probe" (cryobot) which would melt through the ice until it hit the ocean below.[15][83] Once it reached the water, it would deploy an autonomous underwater vehicle (hydrobot) which would gather information and send it back to Earth.[84] Both the cryobot and the hydrobot would have to undergo some form of extreme sterilization to prevent detection of Earth organisms instead of native life and to prevent contamination of the subsurface ocean.[85] This proposed mission has not yet reached a serious planning stage.[86]

See also

References

  1. ↑ 1.0 1.1 Blue, Jennifer (November 9, 2009). "Planet and Satellite Names and Discoverers". USGS. http://planetarynames.wr.usgs.gov/append7.html. Retrieved 2010-01-13. 
  2. ↑ "JPL HORIZONS solar system data and ephemeris computation service". Solar System Dynamics. NASA, Jet Propulsion Laboratory. http://ssd.jpl.nasa.gov/horizons.cgi. Retrieved 2007-08-10. 
  3. ↑ 3.0 3.1 3.2 3.3 Calculated on the basis of other parameters
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 "Overview of Europa Facts". NASA. http://www2.jpl.nasa.gov/galileo/europa/. Retrieved 2007-12-27. 
  5. ↑ 5.0 5.1 Using the mean radius
  6. ↑ See Geissler et al. (1998) in orbit section for evidence of non-synchronous orbit.
  7. ↑ Bills, Bruce G. (2005). "Free and forced obliquities of the Galilean satellites of Jupiter". Icarus 175: 233–247. doi:10.1016/j.icarus.2004.10.028. http://adsabs.harvard.edu/abs/2005Icar..175..233B. 
  8. ↑ 8.0 8.1 Yeomans, Donald K. (2006-07-13). "Planetary Satellite Physical Parameters". JPL Solar System Dynamics. http://ssd.jpl.nasa.gov/?sat_phys_par. Retrieved 2007-11-05. 
  9. ↑ 9.0 9.1 McFadden, Lucy-Ann; Weissman, Paul; and Johnson, Torrence (2007). The Encyclopedia of the Solar System. Elsevier. pp. 432. 
  10. ↑ 10.0 10.1 McGrath (2009). "Atmosphere of Europa". In Pappalardo, Robert T.; McKinnon, William B.; and Khurana, Krishan K.. Europa. University of Arizona Press. ISBN 0-816-52844-6. 
  11. ↑ In US dictionary transcription, us dict: ū·rō′·pə
  12. ↑ Tritt, Charles S. (2002). "Possibility of Life on Europa". Milwaukee School of Engineering. http://people.msoe.edu/~tritt/sf/europa.life.html. Retrieved 2007-08-10. 
  13. ↑ 13.0 13.1 "Tidal Heating". geology.asu.edu. http://web.archive.org/web/20060329000051/http://geology.asu.edu/~glg_intro/planetary/p8.htm. Retrieved 2007-10-20. 
  14. ↑ "NASA and ESA Prioritize Outer Planet Missions". NASA. 2009. http://www.nasa.gov/topics/solarsystem/features/20090218.html. Retrieved 2009-07-26. 
  15. ↑ 15.0 15.1 15.2 15.3 Friedman, Louis (2005-12-14). "Projects: Europa Mission Campaign; Campaign Update: 2007 Budget Proposal". The Planetary Society. http://www.planetary.org/programs/projects/explore_europa/update_12142005.html. Retrieved 2007-08-10. 
  16. ↑ 16.0 16.1 David, Leonard (2006-02-07). "Europa Mission: Lost In NASA Budget". Space.com. http://www.space.com/news/060207_europa_budget.html. Retrieved 2007-08-10. 
  17. ↑ "Simon Marius". Students for the Exploration and Development of Space. University of Arizona. http://seds.lpl.arizona.edu/messier/xtra/Bios/marius.html. Retrieved 2007-08-09. 
  18. ↑ Marius, S.; (1614) Mundus Iovialis anno M.DC.IX Detectus Ope Perspicilli Belgici [1], where he attributes the suggestion to Johannes Kepler
  19. ↑ 19.0 19.1 Marazzini, Claudio (2005). "I nomi dei satelliti di Giove: da Galileo a Simon Marius (The names of the satellites of Jupiter: from Galileo to Simon Marius)". Lettere Italiane 57 (3): 391–407. 
  20. ↑ 20.0 20.1 "Europa, a Continuing Story of Discovery". Project Galileo. NASA, Jet Propulsion Laboratory. http://www2.jpl.nasa.gov/galileo/europa/#overview. Retrieved 2007-08-09. 
  21. ↑ "Planetographic Coordinates". Wolfram Research. 2010. http://documents.wolfram.com/applications/astronomer/AdditionalInformation/PlanetographicCoordinates.html. Retrieved 2010=03-29. 
  22. ↑ Geissler, P. E.; Greenberg, R.; Hoppa, G.; Helfenstein, P.; McEwen, A.; Pappalardo, R.; Tufts, R.; Ockert-Bell, M.; Sullivan, R.; Greeley, R.; Belton, M. J. S.; Denk, T.; Clark, B. E.; Burns, J.; Veverka, J. (January 1998). "Evidence for non-synchronous rotation of Europa". Nature 391 (6665): 368. doi:10.1038/34869. PMID 9450751. http://adsabs.harvard.edu/abs/1998Natur.391..368G. Retrieved 2007-08-09. 
  23. ↑ 23.0 23.1 23.2 Showman, Adam P.; Malhotra, Renu (1997). "Tidal Evolution into the Laplace Resonance and the Resurfacing of Ganymede". Icarus 127: 93–111. doi:10.1006/icar.1996.5669. http://www.lpl.arizona.edu/~showman/publications/showman-malhotra-1997.pdf. 
  24. ↑ "Tidal heating of Io and orbital evolution of the Jovian satellites". 1982. http://adsabs.harvard.edu/full/1982MNRAS.201..415G}accessdate=2008-01-02. 
  25. ↑ Mass of Europa: 48 Yg. Mass of Triton plus all smaller moons: 39.5 Yg (see note g here)
  26. ↑ Jeffrey S. Kargel, Jonathan Z. Kaye, James W. Head, III, et al. (2000). "Europa’s Crust and Ocean: Origin, Composition, and the Prospects for Life". Icarus 148: 226 –265. doi:10.1006/icar.2000.6471. http://www.planetary.brown.edu/pdfs/2440.pdf. 
  27. ↑ Cowen, Ron (2008-06-07). "A Shifty Moon". Science News. http://www.sciencenews.org/view/generic/id/32135/title/A_shifty_moon. 
  28. ↑ 28.0 28.1 Kivelson, Margaret G.; Khurana, Krishan K.; Russell, Christopher T.; Volwerk, Martin; Walker, Raymond J.; and Zimmer, Christophe (2000). "Galileo Magnetometer Measurements: A Stronger Case for a Subsurface Ocean at Europa". Science 289 (5483): 1340–1343. doi:10.1126/science.289.5483.1340. PMID 10958778. http://www.sciencemag.org/cgi/content/abstract/289/5483/1340. 
  29. ↑ 29.0 29.1 "Europa: Another Water World?". Project Galileo: Moons and Rings of Jupiter. NASA, Jet Propulsion Laboratory. 2001. http://www2.jpl.nasa.gov/galileo/moons/europa.html. Retrieved 2007-08-09. 
  30. ↑ Arnett, Bill; Europa (November 7, 1996)
  31. ↑ 31.0 31.1 Hamilton, Calvin J.. "Jupiter's Moon Europa". http://www.solarviews.com/eng/europa.htm. 
  32. ↑ 32.0 32.1 Schenk, Paul M.; Chapman, Clark R.; Zahnle, Kevin; and Moore, Jeffrey M.; Chapter 18: Ages and Interiors: the Cratering Record of the Galilean Satellites, in Jupiter: The Planet, Satellites and Magnetosphere, Cambridge University Press, 2004
  33. ↑ "High Tide on Europa". Astrobiology Magazine. astrobio.net. 2007. http://www.astrobio.net/news/article603.html. Retrieved 2007-10-20. 
  34. ↑ Frederick A. Ringwald (2000-02-29). "SPS 1020 (Introduction to Space Sciences)". California State University, Fresno. http://zimmer.csufresno.edu/~fringwal/w08a.jup.txt. Retrieved 2009-07-04.  (Webcite from 2009-09-20)
  35. ↑ The Effects of Nuclear Weapons, Revised ed., US DOD 1962, pp. 592–593
  36. ↑ Geissler, Paul E.; Greenberg, Richard; et al. (1998). "Evolution of Lineaments on Europa: Clues from Galileo Multispectral Imaging Observations". http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WGF-45K1008-2F&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=e07fc794760364108153faa049c4b4cf. Retrieved 2007-12-20. 
  37. ↑ Figueredo, Patricio H.; and Greeley, Ronald (2003). "Resurfacing history of Europa from pole-to-pole geological mapping". http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WGF-4B28TH7-7&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=ec75f638368d30b181df7d17da020644. Retrieved 2007-12-20. 
  38. ↑ Hurford, Terry A.; Sarid, Alyssa R.; and Greenberg, Richard (2006). "Cycloidal cracks on Europa: Improved modeling and non-synchronous rotation implications". http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WGF-4M645DK-6&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1d983b9bb7b16c980ee900dbaf61e277. Retrieved 2007-12-20. 
  39. ↑ Kattenhorn, Simon A. (2002). "Nonsynchronous Rotation Evidence and Fracture History in the Bright Plains Region, Europa". Icarus 157: 490–506. doi:10.1006/icar.2002.6825. http://adsabs.harvard.edu/abs/2002Icar..157..490K. 
  40. ↑ 40.0 40.1 Sotin, Christophe; Head III, James W.; and Tobie, Gabriel (2001). "Europa: Tidal heating of upwelling thermal plumes and the origin of lenticulae and chaos melting" (PDF). http://planetary.brown.edu/planetary/documents/2685.pdf. Retrieved 2007-12-20. 
  41. ↑ Goodman, Jason C.; Collins, Geoffrey C.; Marshall, John; and Pierrehumbert, Raymond T.. "Hydrothermal Plume Dynamics on Europa: Implications for Chaos Formation" (PDF). http://www-paoc.mit.edu/paoc/papers/europa_plume.pdf. Retrieved 2007-12-20. 
  42. ↑ O'Brien, David P.; Geissler, Paul; and Greenberg, Richard (October 2000). "Tidal Heat in Europa: Ice Thickness and the Plausibility of Melt-Through". Bulletin of the American Astronomical Society 30: 1066. http://adsabs.harvard.edu/abs/2000DPS....32.3802O. 
  43. ↑ Greenberg, Richard (2008). "Unmasking Europa". http://www.springer.com/astronomy/book/978-0-387-47936-1. 
  44. ↑ 44.0 44.1 Greenberg, Richard; Europa: The Ocean Moon: Search for an Alien Biosphere, Springer Praxis Books, 2005
  45. ↑ Greeley, Ronald; et al.; Chapter 15: Geology of Europa, in Jupiter: The Planet, Satellites and Magnetosphere, Cambridge University Press, 2004
  46. ↑ 46.0 46.1 Billings, Sandra E.; and Kattenhorn, Simon A. (2005). "The great thickness debate: Ice shell thickness models for Europa and comparisons with estimates based on flexure at ridges". Icarus 177 (2): 397–412. doi:10.1016/j.icarus.2005.03.013. 
  47. ↑ Zyga, Lisa (12 December 2008). "Scientist Explains Why Jupiter's Moon Europa Could Have Energetic Liquid Oceans". PhysOrg.com. http://www.physorg.com/news148278114.html. Retrieved 2009-07-28. 
  48. ↑ Tyler, Robert H. (11 December 2008). "Strong ocean tidal flow and heating on moons of the outer planets". Nature 456 (7223): 770–772. doi:10.1038/nature07571. PMID 19079055. http://www.nature.com/nature/journal/v456/n7223/abs/nature07571.html. 
  49. ↑ Zimmer, Christophe; and Khurana, Krishan K. (2000). "Subsurface Oceans on Europa and Callisto: Constraints from Galileo Magnetometer Observations" (PDF). Icarus 147: 329–347. doi:10.1006/icar.2000.6456. http://www.igpp.ucla.edu/people/mkivelson/Publications/ICRUS147329.pdf. 
  50. ↑ McCord, Thomas B.; Hansen, Gary B.; et al. (1998). "Salts on Europa's Surface Detected by Galileo's Near Infrared Mapping Spectrometer". http://www.sciencemag.org/cgi/content/abstract/280/5367/1242. Retrieved 2007-12-20. 
  51. ↑ Carlson, Robert W.; Anderson, Mark S.; Mehlman, Robert; and Johnson, Robert E. (2005). "Distribution of hydrate on Europa: Further evidence for sulfuric acid hydrate". http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WGF-4G9Y58G-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=5cf6924793fa56559bb84c45faafd445. Retrieved 2007-12-20. 
  52. ↑ Calvin, Wendy M.; Clark, Roger N.; Brown, Robert H.; and Spencer, John R. (1995). "Spectra of the ice Galilean satellites from 0.2 to 5 µm: A compilation, new observations, and a recent summary". Journal of Geophysical Research 100: 19,041–19,048. doi:10.1029/94JE03349. http://adsabs.harvard.edu/abs/1995JGR...10019041C. 
  53. ↑ Hall, Doyle T.; et al.; Detection of an oxygen atmosphere on Jupiter's moon Europa, Nature, Vol. 373 (23 February 1995), pp. 677–679 (accessed 15 April 2006)
  54. ↑ Savage, Donald; Jones, Tammy; and Villard, Ray (1995-02-23). "Hubble Finds Oxygen Atmosphere on Europa". Project Galileo. NASA, Jet Propulsion Laboratory. http://www2.jpl.nasa.gov/galileo/europa/hst.html. Retrieved 2007-08-17. 
  55. ↑ Kliore, Arvydas J.; Hinson, D. P.; Flasar, F. Michael; Nagy, Andrew F.; Cravens, Thomas E. (July 1997). "The Ionosphere of Europa from Galileo Radio Occultations". Science 277 (5324): 355–358. doi:10.1126/science.277.5324.355. PMID 9219689. http://www.sciencemag.org/cgi/content/abstract/277/5324/355. Retrieved 2007-08-10. 
  56. ↑ "Galileo Spacecraft Finds Europa has Atmosphere". Project Galileo. NASA, Jet Propulsion Laboratory. July 1997. http://www2.jpl.nasa.gov/galileo/status970718.html. Retrieved 2007-08-10. 
  57. ↑ Johnson, Robert E.; Lanzerotti, Louis J.; and Brown, Walter L. (1982). "Planetary applications of ion induced erosion of condensed-gas frosts". http://adsabs.harvard.edu/abs/1982NucIM.198..147J. Retrieved 2007-12-20. 
  58. ↑ Shematovich, Valery I.; Cooper, John F.; and Johnson, Robert E. (April 2003). "Surface-bounded oxygen atmosphere of Europa". EGS - AGU - EUG Joint Assembly (Abstracts from the meeting held in Nice, France). http://adsabs.harvard.edu/abs/2003EAEJA....13094S. Retrieved 2007-08-10. 
  59. ↑ Liang, Mao-Chang; Lane, Benjamin F.; Pappalardo, Robert T.; Allen, Mark; and Yung, Yuk L. (2005). "Atmosphere of Callisto" (PDF). Journal of Geophysical Research 110: E02003. doi:10.1029/2004JE002322. http://yly-mac.gps.caltech.edu/ReprintsYLY/N164Liang_Callisto%2005/Liang_callisto_05.pdf. 
  60. ↑ Smyth, William H.; Marconi, Max L. (August 15, 2007). "Processes Shaping Galilean Satellite Atmospheres from the Surface to the Magnetosphere" (pdf). Abstracts. Workshop on Ices, Oceans, and Fire: Satellites of the Outer Solar System, Boulder, Colorado. pp. 131–132. http://www.lpi.usra.edu/meetings/icysat2007/pdf/6039.pdf. 
  61. ↑ Chyba, Christopher F.; and Hand, Kevin P.; Life without photosynthesis
  62. ↑ 62.0 62.1 Hand, Kevin P.; Carlson, Robert W.; Chyba, Christopher F. (December 2007). "Energy, Chemical Disequilibrium, and Geological Constraints on Europa". Astrobiology 7 (6): 1006–1022. doi:10.1089/ast.2007.0156. PMID 18163875. http://www.liebertonline.com/doi/abs/10.1089/ast.2007.0156. 
  63. ↑ Smyth, William H.; Marconi, Max L. (2006). "Europa's atmosphere, gas tori, and magnetospheric implications". Icarus 181: 510. doi:10.1016/j.icarus.2005.10.019. http://adsabs.harvard.edu/abs/2006Icar..181..510S. 
  64. ↑ Schulze-Makuch, Dirk; and Irwin, Louis N. (2001). "Alternative Energy Sources Could Support Life on Europa" (PDF). Departments of Geological and Biological Sciences, University of Texas at El Paso. http://www.geo.utep.edu/pub/dirksm/geobiowater/pdf/EOS27March2001.pdf. Retrieved 2007-12-21. 
  65. ↑ Exotic Microbes Discovered near Lake Vostok, Science@NASA (December 10, 1999)
  66. ↑ 66.0 66.1 Chandler, David L. (2002-10-20). "Thin ice opens lead for life on Europa". NewScientist.com. http://www.newscientist.com/article.ns?id=dn2929. 
  67. ↑ Jones, Nicola; Bacterial explanation for Europa's rosy glow, NewScientist.com (11 December 2001)
  68. ↑ Phillips, Cynthia; Time for Europa, Space.com (28 September 2006)
  69. ↑ 69.0 69.1 Chamberlin, Sean (1999). "Creatures Of The Abyss: Black Smokers and Giant Worms". Fullerton College. http://earthscape.org/t2/chs01/chs01i/chs01ib.html. Retrieved 2007-12-21. 
  70. ↑ Wilson, Colin P. (2007). "Tidal Heating on Io and Europa and its Implications for Planetary Geophysics". Geology and Geography Dept., Vassar College. http://gsa.confex.com/gsa/2007NE/finalprogram/abstract_117688.htm. Retrieved 2007-12-21. 
  71. ↑ McCollom, Thomas M. (1999). "Methanogenesis as a potential source of chemical energy for primary biomass production by autotrophic organisms in hydrothermal systems on Europa". Woods Hole Oceanographic Institute. http://adsabs.harvard.edu/abs/1999JGR...10430729M. Retrieved 2007-12-21. 
  72. ↑ 72.0 72.1 Marion, Giles M.; Fritsen, Christian H.; Eicken, Hajo; and Payne, Meredith C. (2003). "The Search for Life on Europa: Limiting Environmental Factors, Potential Habitats, and Earth Analogues". Astrobiology. http://www.liebertonline.com/doi/abs/10.1089/153110703322736105?cookieSet=1&journalCode=ast. Retrieved 2007-12-21. 
  73. ↑ Nancy Atkinson (2009). "Europa Capable of Supporting Life, Scientist Says". Universe Today. http://www.universetoday.com/2009/10/08/europa-capable-of-supporting-life-scientist-says/. Retrieved 2009-10-11. 
  74. ↑ Muir, Hazel; Europa has raw materials for life, NewScientist.com (22 May 2002)
  75. ↑ Ringwald, Frederick A. ; SPS 1020 (Introduction to Space Sciences) Course Notes, 2000 February 29
  76. ↑ 76.0 76.1 Berger, Brian; NASA 2006 Budget Presented: Hubble, Nuclear Initiative Suffer Space.com (7 February 2005)
  77. ↑ Rincon, Paul (2009-02-20). "Jupiter in space agencies' sights". BBC News. http://news.bbc.co.uk/1/hi/sci/tech/7897585.stm. Retrieved 2009-02-20. 
  78. ↑ "Cosmic Vision 2015–2025 Proposals". ESA. 2007-07-21. http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=41177. Retrieved 2009-02-20. 
  79. ↑ Goodman, Jason C.; Re: Galileo at Europa, MadSci Network forums, September 9, 1998
  80. ↑ McKay, Christopher P. (2002). "Planetary protection for a Europa surface sample return: The ice clipper mission". Advances in Space Research 30 (6): 1601–1605. doi:10.1016/S0273-1177(02)00480-5. 
  81. ↑ P. Weiss, K.L. Yung, N. Koemle, S.M. Ko, E. Kaufmann, G. Kargl ; Thermal drill sampling system onboard high-velocity impactors for exploring the subsurface of Europa, Advances in Space Research (18 January 2010)
  82. ↑ Hsu, J.. "Dual Drill Designed for Europa’s Ice". Astrobiology Magazine. http://www.astrobio.net/exclusive/3463/dual-drill-designed-for-europa’s-ice. 
  83. ↑ Knight, Will; Ice-melting robot passes Arctic test, NewScientist.com (14 January 2002)
  84. ↑ Bridges, Andrew; Latest Galileo Data Further Suggest Europa Has Liquid Ocean, Space.com (10 January 2000)
  85. ↑ National Academy of Sciences Space Studies Board, Preventing the Forward Contamination of Europa, National Academy Press, Washington (DC), June 29, 2000
  86. ↑ Powell, Jesse; Powell, James; Maise, George; and Paniagua, John (July 2005). "NEMO: A mission to search for and return to Earth possible life forms on Europa". Acta Astronautica 57 (2–8): 579–593. doi:10.1016/j.actaastro.2005.04.003. 

Further reading

External links

[1] Protection policies for Europa.

Moons of Jupiter
Listed in increasing distance from Jupiter. Temporary names in italics.
Inner moons
Galilean moons
Io · Europa · Ganymede · Callisto
 
Themisto
Himalia group
Leda · Himalia · Lysithea · Elara · S/2000 J 11
 
Carpo · S/2003 J 12
Ananke group
core
Ananke · Praxidike · Harpalyke · Iocaste · Euanthe · Thyone
peripheral
Euporie · S/2003 J 3 · S/2003 J 18 · Thelxinoe · Helike · Orthosie · S/2003 J 16 · Hermippe · Mneme · S/2003 J 15
Carme group
Herse · S/2003 J 10 · Pasithee · Chaldene · Arche · Isonoe · Erinome · Kale · Aitne · Taygete · S/2003 J 9 · Carme · S/2003 J 5 · S/2003 J 19 · Kalyke · Eukelade · Kallichore
Pasiphaë group
Eurydome · S/2003 J 23 · Hegemone · Pasiphaë · Sponde · Cyllene · Megaclite · S/2003 J 4 · Callirrhoe · Sinope · Autonoe · Aoede · Kore
 
S/2003 J 2
Rings of Jupiter · In fiction
Natural satellites of the Solar System
Planetary satellites
Terrestrial · Martian · Jovian · Saturnian · Uranian · Neptunian
Other satellite systems
Largest satellites
Ganymede · Titan · Callisto · Io · Moon · Europa · Triton
Titania · Rhea · Oberon · Iapetus · Charon · Umbriel · Ariel · Dione · Tethys  · Enceladus · Miranda · Proteus · Mimas
Inner satellites · Trojans · Irregulars · List · Timeline of discovery · Naming
Jupiter
Characteristics Jupiter.jpg
Moons
Io  · Europa · Ganymede · Callisto
Himalia group · Carme group · Ananke group · Pasiphaë group
Trojans
Greek camp · Trojan camp
Exploration
Pioneer program (Pioneer 10  · Pioneer 11) · Voyager program (Voyager 1  · Voyager 2) · Ulysses · Galileo · Cassini · New Horizons · Juno · Europa Jupiter System Mission (Jupiter Europa Orbiter · Jupiter Ganymede Orbiter) · Colonization of Europa
Miscellaneous
Comet Shoemaker-Levy 9 · 2009 Jupiter impact event · Jupiter-crossing minor planets · Jupiter (mythology) · Jupiter in fiction · Jupiter's moons in fiction
Wikipedia book Book:Jupiter · Category Category:Jupiter  · Portal Portal:Solar System
Atmospheres
Major
Sun · Venus · Earth · Mars · Jupiter · Saturn · Titan · Uranus · Neptune · Triton · Pluto  · HD 209458 b
 Toward the top of Earth's atmosphere
Tenuous
Mercury · Moon · Io · Europa · Ganymede · Callisto · Enceladus · Rhea
See also
Stellar atmosphere · Coma (cometary) · Extraterrestrial atmospheres
Extraterrestrial life
Events and objects

ALH84001 · Close encounter · Murchison meteorite · Radio source SHGb02+14a · Shergotty meteorite · Wow! signal
Extraterrestrial
bodies

Europa · Mars · Titan · Enceladus

Goldilocks planet · Gliese 581 g  · Gliese 581 d
Communication

Allen Telescope Array · Arecibo Observatory · Bracewell probe · Communication with Extraterrestrial Intelligence · Lincos (language) · Pioneer plaque · Project Cyclops · Project Ozma · Project Phoenix · SERENDIP · SETI · SETI@home · Active SETI
Related topics

Astrobiology · Astroecology · Biosignature · Brookings Report · Catalog of Nearby Habitable Systems · Exopolitics · Exotheology · Extraterrestrials in fiction · Extraterrestrial liquid water · Habitable zone · Habitability of red dwarf systems · Hypothetical types of biochemistry · Interstellar communication · Noogenesis · Planetary habitability · Planetary protection · San Marino Scale · Shermer's Last Law · Silencium universi · Xenoarchaeology · Xenolinguistics
Theories

Ancient astronauts · Aurelia and Blue Moon · Back-contamination · Cosmic pluralism · Drake equation · Fermi paradox · Great Filter · Kardashev scale · Mediocrity principle · Neocatastrophism · Panspermia · Planetarium hypothesis · Rare Earth hypothesis · Sentience quotient · Zoo hypothesis
Missions

Mars sample return mission · Mars Astrobiology Explorer-Cacher · Darwin space mission · ExoMars
Exhibitions

The Science of Aliens
The Solar System
The Sun Mercury Venus The Moon Earth Mars Phobos and Deimos Ceres The main asteroid belt Jupiter Moons of Jupiter Rings of Jupiter Saturn Moons of Saturn Rings of Saturn Uranus Moons of Uranus Rings of Uranus Neptune Rings of Neptune Pluto Moons of Pluto Haumea Makemake The Kuiper Belt Eris Dysnomia The Scattered Disc The Hills Cloud The Oort CloudSolar System Template Final.png
Moons (Terrestrial · Martian · Jovian · Saturnian · Uranian · Neptunian · Plutonian · Haumean · Eridian) · Rings (Jovian · Saturnian · Uranian · Neptunian)
Related articles: astronomical object, star, planet, dwarf planet, small body and planetary system
See also the Solar System's list of objects, sorted by size, the list of minor planets, or the Solar System Portal

References

  1. ↑ http://www2.jpl.nasa.gov/galileo/europa/