Jupiter, in Roman religion and mythology
Jupiter, in Roman religion and mythology, the supreme god, also called Jove. Originally a sky deity associated with rain and agriculture, he developed into the great father god, prime protector of the state, concerned, like the Greek Zeus Zeus , in Greek religion and mythology, son and successor of Kronos as supreme god. His mother, Rhea, immediately after his birth concealed him from Kronos, who, because he was fated to be overthrown by one of his children, ate all his offspring...... Click the link for more information. (with whom he is identified), with all aspects of life. At his temple on the Capitol, triumphant generals honored him with their spoils and magistrates paid homage to him with sacrifices. Jupiter was the son of Saturn Saturn, in Roman religion and mythology, god of harvests, later identified with the Greek Kronos. Little is known of the origins of his cult. His reign was regarded as the Golden Age.
..... Click the link for more information. and Ops Ops , in Roman religion, goddess of harvests. She was the wife of Saturn, by whom she bore Jupiter and Juno. At her festivals, the Opiconsivia and the Opalia, held in August and December, respectively, she was worshiped as a goddess of sowing and reaping and was
..... Click the link for more information. and the brother and husband of Juno Juno, in Roman religion and mythology, wife and sister of Jupiter. In early Roman times she, like the Greek Hera (with whom she was later identified), was goddess and protector of women, concerned especially with their sexual life.
..... Click the link for more information. .
Jupiter, in astronomy
Jupiter (j
`pətər), in astronomy, 5th planet from the sun and largest planet of the solar system.
Astronomical and Physical Characteristics
Jupiter's orbit lies beyond the asteroid asteroid, planetoid, or minor planet, small body orbiting the sun. More than 10,000 asteroids have orbits sufficiently well known to have been cataloged and named; thousands more exist.
..... Click the link for more information. belt at a mean distance of 483.6 million mi (778.3 million km) from the sun; its period of revolution is 11.86 years. In order from the sun it is the first of the Jovian planets—Jupiter, Saturn Saturn, in astronomy, 6th planet from the sun.
Astronomical and Physical Characteristics of Saturn
Saturn's orbit lies between those of Jupiter and Uranus; its mean distance from the sun is c.886 million mi (1.
..... Click the link for more information. , Uranus Uranus , in astronomy, 7th planet from the sun, at a mean distance of 1.78 billion mi (2.87 billion km), with an orbit lying between those of Saturn and Neptune; its period of revolution is slightly more than 84 years.
..... Click the link for more information. , and Neptune Neptune, in astronomy, 8th planet from the sun at a mean distance of about 2.8 billion mi (4.5 billion km) with an orbit lying between those of Uranus and the dwarf planet Pluto; its period of revolution is about 165 years.
..... Click the link for more information. —very large, massive planets of relatively low density, having rapid rotation and a thick, opaque atmosphere. Jupiter has a diameter of 88,815 mi (142,984 km), more than 11 times that of the earth. Its mass is 318 times that of the earth and about 2 1-2 times the mass of all other planets combined.
The atmosphere of Jupiter is composed mainly of hydrogen, helium, methane, and ammonia. However, the concentration of nitrogen, carbon, sulfur, argon, xenon, and krypton—as measured by an instrument package dropped by the space probe Galileo during its 1995 flyby of the planet—is more than twice what was expected, raising questions about the accepted theory of Jupiter's formation. The atmosphere appears to be divided into a number of light and dark bands parallel to its equator and shows a range of complex features, including a storm called the Great Red Spot. Located in the southern hemisphere and varying from c.15,600 to 25,000 mi (25,000 to 40,000 km) in one direction and 7,500 to 10,000 mi (12,000 to 16,000 km) in the other, the storm rotates counterclockwise and has been observed ever since 1664, when Robert Hooke first noted it. Also in the southern hemisphere is the Little Red Spot, c.8,000 mi (13,000 km) across. It formed from three white-colored storms that developed in the 1940s, merged in 1998–2000, and became clearly red by 2006. Analysis of the data obtained when massive pieces of the comet Shoemaker Levy 9 plunged into Jupiter in 1994 has extended our knowledge of the Jovian atmosphere.
Jupiter has no solid rock surface. One theory pictures a gradual transition from the outer ammonia clouds to a thick layer of frozen gases and finally to a liquid or solid hydrogen mantle. Beneath that Jupiter probably has a core of rocky material with a mass 10–15 times that of the earth. The spot and other markings of the atmosphere also provide evidence for Jupiter's rapid rotation, which has a period of about 9 hr 55 min. This rotation causes a polar flattening of over 6%. The temperature ranges from about −190°F; (−124°C;) for the visible surface of the atmosphere, to 9°F; (−13°C;) at lower cloud levels; localized regions reach as high as 40°F; (4°C;) at still lower cloud levels near the equator. Jupiter radiates about four times as much heat energy as it receives from the sun, suggesting an internal heat source. This energy is thought to be due in part to a slow contraction of the planet. Jupiter is also characterized by intense nonthermal radio emission; in the 15-m range it is the strongest radio source in the sky. Jupiter has a huge asymetrical magnetic field, extending past the orbit of Saturn in one direction but far less in the direction of the sun. This magnetosphere traps high levels of energetic particles far more intense than those found within earth's Van Allen radiation belts Van Allen radiation belts, two belts (sometimes considered as a single belt of varying intensity) of radiation outside the earth's atmosphere, extending from c.400 to c.40,000 mi (c.650–c.65,000 km) above the earth.
..... Click the link for more information. . Six space probes space probe, space vehicle carrying sophisticated instrumentation but no crew, designed to explore various aspects of the solar system (see space exploration).
..... Click the link for more information. have encountered the Jovian system: Pioneers 10 and 11 (1973 and 1974), Voyagers 1 and 2 (both 1979), Ulysses (1992), and Galileo (1995–2003).
Its Moons and Rings
At least 63 natural satellites orbit Jupiter. They are conveniently divided into six main groups (in order of increasing distance from the planet): Amalthea, Galilean, Himalia, Ananke, Carme, and Pasiphae. The first group is comprised of the four innermost satellites—Metis, Adrastea, Amalthea, and Thebe. The red color of
Amalthea (diameter: 117 mi/189 km), a small, elongated satellite discovered (1892) by Edward Barnard Barnard, Edward Emerson, 1857–1923, American astronomer, b. Nashville, Tenn., grad. Vanderbilt Univ., 1887. From 1887 to 1895 he was astronomer at Lick Observatory in California, and from 1895 he was professor of practical astronomy at the Univ.
..... Click the link for more information. , probably results from a coating of sulfur particles ejected from Io.
Metis (diameter: 25 mi/40 km),
Adrastea (diameter: 12 mi/20 km), and
Thebe (diameter: 62 mi/100 km) are all oddly shaped and were discovered in 1979 in photographs returned to earth by the Voyager 1 space probe. Metis and Adrastea orbit close to Jupiter's thin ring system; material ejected from these moons helps maintain the ring.
The four largest satellites—Io, Europa, Ganymede, and Callisto—were discovered by Galileo in 1610, shortly after he invented the telescope, and are known as the Galilean satellite group.
Io (diameter: 2,255 mi/3,630 km), the closest to Jupiter of the four, is the most active geologically, with 30 active volcanoes that are probably energized by the tidal effects of Jupiter's enormous mass.
Europa (diameter: 1,960 mi/3,130 km) is a white, highly reflecting body whose smooth surface is covered with dark streaks up to 43 mi/70 km in width and from several hundred to several thousand miles in length.
Ganymede (diameter: 3,268 mi/5,262 km), second most distant of the four and the largest satellite in the solar system, has heavily cratered regions, tens of miles across, that are surrounded by younger, grooved terrain.
Callisto (diameter: 3,000 mi/4,806 km), the most distant and the least active geologically of the four, has a heavily cratered surface.
Themisto (diameter: 5 mi/8 km) orbits Jupiter midway between the Galilean and next main group of satellites, the Himalias. The Himalia group consists of five tightly clustered satellites with orbits outside that of Callisto—
Leda (diameter: 6 mi/10 km),
Himalia (diameter: 106 mi/170 km),
Lysithea (diameter: 15 mi/24 km),
Elara (diameter: 50 mi/80 km), and
S/2000 J11 (diameter: 2.5 mi/4 km). These 14 inner satellites are regular, that is, their orbits are relatively circular, near equatorial, and prograde, i.e., moving in the same orbital direction as the planet. Almost all of the remainder are irregular in that their orbits are large, elliptical, inclined to that of the planet, and usually retrograde, i.e., motion opposite to that of the planet's rotation. (Jupiter's irregular satellites are distinguished from the regular by the spelling of their names, which all end in the letter "e".)
Situated between the Himalia and Ananke groups is Carpo (diameter: 2 mi/3 km), which like Thermisto doesn't seem to fit into any of the main groups. The Ananke group comprises 17 satellites, which share similar orbits and range from 1.2 to 2.5 mi (2–4 km) in diameter except for two:
S/2003 J12,
Euporie,
Orthosie,
Euanthe,
Thyone,
Mneme,
Harpalyke,
Hermippe,
Praxidike (diameter: 4.5 mi/7 km),
Thelexinoe,
Iocaste,
Ananke (diameter: 12.5 mi/20 km),
S/2003 J16,
S/2003 J3,
S/2003 J18,
Helike, and
S/2003 J15.
Like the Ananke group, the Carme group is remarkably homogeneous. It comprises 17 satellites, which share similar orbits and, except for one, range from 1.2 to 3 mi (2–5 km) in diameter:
Arche,
Pasithee,
Chaldene,
Kale,
Isonoe,
Aitne,
Erinome,
Taygete,
Carme (diameter: 28 mi/46 km),
Kalyke,
Eukelade,
Kallichore,
S/2003 J17,
S/2003 J10,
S/2003 J9,
S/2003 J5, and
S/2003 J19. The most distant of the groups from the planet is the Pasiphae, which comprises 14 widely dispersed satellites that, except for two, range from 1.2 to 4.5 mi (2–7 km) in diameter:
S/2000 J12,
Eurydome,
Autonoe,
Sponde,
Pasiphae (diameter: 36 mi/58 km),
Megaclite,
Sinope (diameter: 23 mi/38 km),
Hegemone,
Aode,
Callirrhoe,
Cyllene,
S/2000 J23,
S/2000 J4, and
S/2000 J14. The odd orbits of the irregular satellites indicate that they were captured after Jupiter's formation. Because they are small, irregularly shaped, and clustered into groups, it is believed that they originated as parts of a larger body that either shattered due to Jupiter's enormous gravity or broke apart in a collision with another body.
Jupiter has three rings ring, in astronomy, relatively thin band of rocks and dust and ice particles that orbit around a planet in the planet's equatorial plane. All four of the giant planets in the solar system—Jupiter, Saturn, Uranus, and Neptune— have rings, although only
..... Click the link for more information. —
Halo,
Main, and
Gossamer—similar to those of Saturn but much smaller and fainter. An intense radiation belt lies between the rings and Jupiter's uppermost atmospheric layers.
Jupiter
)
Jupiter
or JoveChief god of ancient Rome and Italy. Like his Greek counterpart, Zeus, he was worshiped as a sky god. With Juno and Minerva he was a member of the triad of deities traditionally believed to have been introduced into Rome by the Etruscans. Jupiter was associated with treaties, alliances, and oaths; he was the protecting deity of the republic and later of the reigning emperor. His oldest temple was on the Capitoline Hill in Rome. He was worshiped on the summits of hills throughout Italy, and all places struck by lightning became his property. His sacred tree was the oak.
Jupiter1
Jupiter2
Jupiter [′jü·pəd·ər]
| jupiter - To kill an IRC robot or user and then take its place by adopting its nick so that it cannot reconnect. Named after a particular IRC user who did this to NickServ, the robot in charge of preventing people from inadvertently using a nick claimed by another user. |
Jupiter
the fifth planet from the sun in our solar system; astronomical symbol, 
.
General information. Jupiter, the largest of the Jovian planets, has been known since antiquity. It revolves around the sun at a mean distance of 5.203 astronomical units (778 million km). Its orbit has an eccentricity of 0.048, and the inclination of its orbital plane to the plane of the ecliptic is 1.3°. Jupiter completes one revolution around the sun in 11,862 years, traveling at an average velocity of 13.06 km/sec. The mean synodic period of revolution is 399 days. In 12 years Jupiter traverses the entire sky along the ecliptic and can be seen at opposition as a pale yellowish star of stellar magnitude – 2.6; at favorable opposition it is surpassed only by Venus and Mars in brightness. Its visible disk has the form of an ellipse, whose axes at mean opposition can be seen at an angle of 46.5″ and 43.7″. At conjunction with the sun, Jupiter’s angular dimensions are one-third smaller and its brightness is 0.84 stellar magnitude fainter than at oppositions. The visual albedo is 0.67.
Jupiter’s equatorial diameter is 142,600 km, and its polar diameter, 134,140 km; the planet’s oblateness (1/15.9) is due to its rapid axial rotation. The rotation period is 9 hr 50 min 30 sec near the equator (System I) and 9 hr 55 min 40 sec at middle latitudes (System II). Jupiter’s volume exceeds the volume of the earth by a factor of 1,315, while its mass exceeds the earth’s mass by a factor of 318. Jupiter’s mass is 1/1047.39 the mass of the sun. Its mean density (1.33 g/cm3) differs little from the solar density. The acceleration of gravity is 27.90 m/sec2 at the poles and 25.90 m/sec2 at the equator; the centrifugal acceleration at the equator is 2.25 m/sec2. The escape velocity from Jupiter’s surface is 61 km/sec. (All the geometrical, mechanical, and physical characteristics are from 1974 data.) Information on Jupiter and its satellites was greatly enriched by the measurements and observations made by the American space probes Pioneer 10 (1973) and Pioneer 11 (1974).
Atmosphere. Jupiter’s observable surface consists of clouds and other atmospheric formations and is crossed by numerous dark bands (belts) separated by light zones running parallel to the equator, which is inclined only 3°04′ to Jupiter’s orbital plane. The bands display a variety of colors and have a complex structure that is constantly changing. The appearance of the north and south equatorial bands, which disappear and reappear with an established cyclicity of about four years, is especially variable. The very narrow equatorial band also sometimes becomes invisible. By contrast, the circumpolar regions are comparatively stable.
The amount of solar heat incident per unit area of Jupiter is 51.0 W/m2, that is, it is smaller by a factor of 27 than the amount of heat incident on the earth. It is capable of heating the surface of Jupiter to an equilibrium temperature of 110°K. However, direct measurements by both ground-based equipment and space probes indicate a temperature of up to 145°K from measurements in the infrared radiation of Jupiter and even higher values, up to 170°K, in the microwave region. In some parts of the dark bands, infrared radiation at very long waves implies temperatures of 200°–270°K. A record high temperature of 310°K was detected in one dark spot (6,000 × 12,000 km) near the equator. Such a temperature can result only from a flow of heat from the planet’s interior that exceeds the heat coming from the sun by a factor of 2.
Jupiter’s cloud structure contains more or less constant formations, such as the Great Red Spot, located at a latitude of about 22° in the southern tropical zone. The Great Red Spot is oval in shape, with a length of about 40,000 km and a width of about 13,000 km. Although its color is red, there are years when it can be distinguished only with difficulty against the white background of the zone. Rotational effects and vertical movements in the atmosphere, combined with different cloud levels, are responsible for the complex dependence of the visible systematic motions at various distances from the equator. The rotation periods System I and System II describe only the average rotation of Jupiter’s atmosphere. In fact, systematically directed winds, acting in a given belt or zone, lead to markedly different values of the period of rotation.
The chemical composition of Jupiter’s atmosphere has been determined spectroscopically. Methane (CH4) and ammonia (NH3) were the first compounds detected in Jupiter’s atmosphere on the basis of the strong absorption bands. Subsequently, molecular hydrogen (H2), water vapor (H2O), and the molecules of acetylene (C2H2), ethane (C2H6), phosphene (PH3), and finally carbon monoxide (CO) were detected from weak absorption bands in the infrared region of the spectrum.
The dark bands of Jupiter are aerosol-like, consisting of particles measuring 0.2–0.3 ptm. Ammonia crystals have been detected above the level where the atmospheric pressure is 1 atmosphere (the geometrical dimensions of Jupiter given above correspond to this level). Solid polysulfide particles are located somewhat below this level, ice crystals are found still lower, and finally, 60 km below this level, suspended drops of an ammonia-water solution are found.
Internal structure. There are several models of Jupiter’s structure based on different assumptions regarding its chemical composition. Because of Jupiter’s strong gravity, the gas pressure increases very rapidly with depth, and even at a distance of 10,000 km from the surface it becomes so great that the predominant gas, hydrogen, undergoes a change of state, from the normal molecular phase to the metallic. The temperature increases as the center of the planet is approached, and consequently the metallic hydrogen melts (the temperature near the center of Jupiter approaches 20,000°K at a pressure of the order of 100 million atmospheres and a density of 20–30 g/cm3). Some models of Jupiter assume the existence of an ice layer (H2O) of significant thickness, but only near the surface, where the temperature is low.
Apparently, Jupiter has a solid shell comparatively close to the surface. The assumption that such a shell exists could explain the magnetic field, which rigidly rotates together with the planet, and the inhomogeneities of the heat fluxes, which are manifested in numerous details of the bands and especially in the long-existing Great Red Spot, which rotates with nearly the same period as Jupiter’s magnetic field.
Magnetic field. Jupiter’s magnetic field has been detected from strong radio-frequency radiation, which is especially intense at decimeter and decameter wavelengths. Decimeter waves originate from near-planetary space and are synchrotron radiation of electrons trapped by Jupiter’s magnetosphere in radiation belts similar to those of the earth. The decameter radiation (at a 7.5-m wavelength) is in the form of noise storms, lasting from a few hours to a few minutes. The radiation is directed and originates from certain small areas on Jupiter’s surface. It follows from the periodic recurrence of the radio outbursts that their sources rotate with a period of 9 hr 55 min 30 sec (System III). The decimeter radiation also changes with this period. It is this period that is ascribed to the rotation of the solid layer that actually forms the surface of Jupiter. The nature of Jupiter’s solid layer remains unknown (as of the 1970’s). Its upper boundary should be located near the visible surface, and its lower boundary may be located where the metallic hydrogen changes from the solid phase to the liquid. Electrical currents that are responsible for Jupiter’s magnetic field arise at this boundary and within the liquid core. The strength of Jupiter’s magnetic field is 4 oersteds. The direction of its magnetic axis forms an angle of about 10° with its axis of rotation.
Jupiter’s magnetosphere is very large. In the regions closest to the planet (up to 20 radii from the planet), it has a marked dipole character and includes radiation belts, containing field-trapped electrons with energies above 6 megaelectron volts. The interaction of the electrons with the field gives rise to decimeter synchrotron radiation. In more distant regions, the central magnetosphere extends to a distance of 60 Jupiter radii and is deformed by rotation. Plasma emissions and oscillations that emit in the decameter band are possible here. The outer magnetosphere, which extends to the magnetopause, whose size is variable, is located still farther out, up to 90–100 Jupiter radii from the planet. On the far side it extends beyond Saturn’s orbit. All five of the satellites closest to Jupiter lie within the central magnetosphere. The closest large satellite—Io—apparently has its own magnetic field and significantly influences the frequency of Jupiter’s radio outbursts.
Satellites. Thirteen satellites of Jupiter are known. Satellite XIII (JXIII) was the last to be discovered (1974). The first four satellites, which are also the largest, were discovered by Galileo in 1610. The fifth satellite—JV, discovered in 1892, nearly three centuries later—is the closest to the planet, only 2.54 Jupiter equatorial radii from the planet. All of these five satellites move essentially in circular orbits, whose planes coincide with the plane of Jupiter’s equator. Their periods of revolution range from 12 hr for JV to 16.8 days for JIV. The remaining satellites of Jupiter, all of which have been discovered in the 20th century, lie at greater distances from the planet.
In 1976 the names of all the satellites were officially confirmed. Nearly all are named after mythological figures in one way or another associated with Jupiter (the first four satellites were named
| Table 1. Jupiter’s satellites1 | ||
|---|---|---|
| Satellite | Radius (km) | Stellar magnitude at opposition |
| 11976 data | ||
| Io(JI) ............... | 1,820 | 49 |
| Europa (JII) ............... | 1,530 | 5.3 |
| Ganymede (JIII) ............... | 2,610 | 46 |
| Callista (JIV) ............... | 2,450 | 5.6 |
| Amalthea (JV) ............... | 120 | 13 |
| Himalia (JVI) ............... | ~80 | 142 |
| Elara(JVII) ............... | ~50 | 17 |
| Pasiphae(JVIII) ............... | ~12 | 18 |
| Sinope(JIX) ............... | ~10 | 18.6 |
| Lysithea (JX) ............... | ~8 | 188 |
| Carme (JXI) ............... | ~9 | 186 |
| Ananke(JXII) ............... | ~8 | 18.7 |
| Leda (JXIII) ............... | ~5 | 20 |
by Galileo). Table 1 lists Jupiter’s satellites, along with a number of their characteristics.
The four Galilean satellites are the sizes of planets (Ganymede and Callisto are larger than Mercury). Their periods of axial rotation and revolution around Jupiter coincide. Their average densities are higher than the density of Jupiter: 2.89, 3.20, 2.07, and 1.54 g/cm3. They all have low temperatures, close to the equilibrium temperature. Their albedos are quite high but lower than Jupiter’s albedo, implying the presence of surface features rather than the presence of a thick atmosphere. Indeed, radar and infrared observations have established that their surfaces consist of ice or an ice-rock mixture, since sizable irregularities have been observed. Pioneer 10 and Pioneer 11 photographed Ganymede from nearby, revealing stable dark and light formations. Io has been found to have an atmosphere and a significant ionosphere. It may be assumed from the close coincidence of the planes of the first five satellites with Jupiter’s equatorial plane that the satellites were formed at the same time as the planet from one cluster of primary material. As far as the other satellites are concerned, they most probably were asteroids at one time in the past and were captured by Jupiter.
REFERENCES
Moroz, V. I. Fizika planet. Moscow, 1967.Fizicheskie kharakteristiki planet-giganlov. Alma-Ata, 1971.
Zharkov. V. N. Vnutrennee stroenie Zemli, Luny i planet. Moscow, 1973.
Dolginov, Sh. Sh. Magnetizmplanet. Moscow, 1974.
Martynov, D. Ia. Planety: Reshennye i nereshennye problemy. Moscow, 1970.
Zemlia i Vselennaia. (Articles and comments on Jupiter for the period 1974–77.)
D. IA. MARTYNOV
Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|