Jupiter Planet statistics Distance from the Sun (in millions) Maximum: 505.7 miles 815.7 km 5.455 AU Minimum: 459.4 miles 740.9 km 4.951 AU Mean: 482.6 miles 778.3 km 5.203 AU Period of revolution ("one year"): 11.86 years Period of rotation (equatorial): 9 hr. 50 min. 30 sec. Mean orbital velocity per second: 8.1 miles (13.1 km) Inclination of axis: 3.1░ Orbital eccentricity: 0.048 Orbital inclination: 1.31░ Diameter at equator: 89,424 miles 143,884 km 11.2 x Earth's diameter Oblateness: 0.064 Escape velocity per second: 37.0 miles (59.5 km) Mean surface temperature: -238 F / -150 C / 123░ K (at cloud tops) Mass 1.9 x 10^30 kg (Earth = 1): 318 Volume (Earth =1): 1,319 Density (water = 1): 1.33 Surface gravity: 22.9 m/s^2 (Earth = 1): 2.64 Maximum apparent diameter as seen from Earth (seconds of arc): 50".1 Mean diameter of Sun as seen from the planet: 6' 09" Albedo: 0.44 Number of knwon satellites: 16 Satellite data Metis Mean distance from center of planet: 79,530 mi. (127,960 km) Orbital period: 0.295 days Orbital eccentricity: 0 Orbital inclination to planet's equator: 0░ Diameter: 25 mi. (40 km) Escape velocity: 0.010? mph (0.02? kph) Magnitude: 17.4 Maximum apparent diameter as seen from the planet: --- Adrastea Mean distance from center of planet: 80,160 mi. (128,980 km) Orbital period: 0.298 days Orbital eccentricity: 0 Orbital inclination to planet's equator: 0░ Diameter: 16 x 12 x 10 mi. (26 x 20 x 16 km) Escape velocity: 0.006? mph (0.01? kph) Magnitude: 18.9 Maximum apparent diameter as seen from the planet: --- Amalthea Mean distance from center of planet: 112,680 mi. (181,300 km) Orbital period: 0.498 days Orbital eccentricity: 0.003 Orbital inclination to planet's equator: 0.45░ Diameter: 163 x 91 x 83 mi. (262 x 146 x 134 km) Escape velocity: 0.010? mph (0.16? kph) Magnitude: 14.1 Maximum apparent diameter as seen from the planet: 7' 24" Thebe Mean distance from center of planet: 137,900 mi. (221,900 km) Orbital period: 0.675 days Orbital eccentricity: 0.013 Orbital inclination to planet's equator: 0.9░ Diameter: 68 x 62 x 56 mi. (110 x 100 x 90 km) Escape velocity: 0.006? mph (0.1? kph) Magnitude: 15.5 Maximum apparent diameter as seen from the planet: --- Io Mean distance from center of planet: 262,030 mi. (421,600 km) Orbital period: 1.769 days Orbital eccentricity: 0.004 Orbital inclination to planet's equator: 0.04░ Diameter: 2, 264 mi. (3,642 km) Escape velocity: 1.590 mph (2.56 kph) Magnitude: 5.0 Maximum apparent diameter as seen from the planet: 35' 40" Europa Mean distance from center of planet: 416,970 mi. (670,900 km) Orbital period: 3.551 days Orbital eccentricity: 0.009 Orbital inclination to planet's equator: 0.47░ Diameter: 1,945 mi. (3,130 km) Escape velocity: 1.310 mph (2.10 kph) Magnitude: 5.3 Maximum apparent diameter as seen from the planet: 17' 30" Ganymede Mean distance from center of planet: 665,000 mi. (1.,070,000 km) Orbital period: 7.155 days Orbital eccentricity: 0.002 Orbital inclination to planet's equator: 0.21░ Diameter: 3,274 mi. (5,268 km) Escape velocity: 1.730 mph (2.78 kph) Magnitude: 4.6 Maximum apparent diameter as seen from the planet: 18' 06" Callisto Mean distance from center of planet: 1,168,400 mi. (1,880,000 km) Orbital period: 16.689 days Orbital eccentricity: 0.007 Orbital inclination to planet's equator: 0.51░ Diameter: 2,987 mi. (4,806 km) Escape velocity: 1.510 mph (2.43 kph) Magnitude: 5.6 Maximum apparent diameter as seen from the planet: 9' 30" Leda Mean distance from center of planet: 6,805,000 mi. (11,094,000 km) Orbital period: 238.7 days Orbital eccentricity: 0.148 Orbital inclination to planet's equator: 26.1░ Diameter: 6 mi. (10 km) Escape velocity: 0.003? mph (0.005? kph) Magnitude: 20.2 Maximum apparent diameter as seen from the planet: 0" .2 Himalia Mean distance from center of planet: 7,134,900 mi. (11,480,000 km) Orbital period: 250.6 days Orbital eccentricity: 0.158 Orbital inclination to planet's equator: 27.6░ Diameter: 106 mi. (170 km) Escape velocity: 0.060? mph (0.1? kph) Magnitude: 14.8 Maximum apparent diameter as seen from the planet: 8" .2 Lysithea Mean distance from center of planet: 7,284,000 mi. (11,720,000 km) Orbital period: 259.2 days Orbital eccentricity: 0.107 Orbital inclination to planet's equator: 29.0░ Diameter: 15 mi. (24 km) Escape velocity: 0.006? mph (0.01? kph) Magnitude: 18.4 Maximum apparent diameter as seen from the planet: 0" .1 Elara Mean distance from center of planet: 7,295,000 mi. (11,737,000 km) Orbital period: 259.7 days Orbital eccentricity: 0.207 Orbital inclination to planet's equator: 24.8░ Diameter: 50 mi. (80 km) Escape velocity: 0.030? mph (0.05? kph) Magnitude: 16.7 Maximum apparent diameter as seen from the planet: 1" .4 Ananke Mean distance from center of planet: 13,176,000 mi. (21,200,000 km) Orbital period: 631 days Orbital eccentricity: 0.17 Orbital inclination to planet's equator: 147░ Diameter: 12 mi. (20 km) Escape velocity: 0.006? mph (0.01? kph) Magnitude: 18.9 Maximum apparent diameter as seen from the planet: 0" .02? Carme Mean distance from center of planet: 14,046,000 mi. (22,600,000 km) Orbital period: 692 days Orbital eccentricity: 0.21 Orbital inclination to planet's equator : 164░ Diameter: 19 mi. (30 km) Escape velocity: 0.010? mph (0.02? kph) Magnitude: 18.0 Maximum apparent diameter as seen from the planet: 0" .02? Pasiphaδ Mean distance from center of planet: 14,605,000 mi. (23,500,000 km) Orbital period: 735 days Orbital eccentricity: 0.38 Orbital inclination to planet's equator: 145░ Diameter: 22 mi. (36 km) Escape velocity: 0.01? mph (0.02? kph) Magnitude: 17.7 Maximum apparent diameter as seen from the planet: 0" .02? Sinope Mean distance from center of planet: 14,730,000 mi. (23,700,000 km) Orbital period: 758 days Orbital eccentricity: 0.28 Orbital inclination to planet's equator: 153░ Diameter: 17 mi. (28 km) Escape velocity: 0.006? mph (0.01? kph) Magnitude: 18.3 Maximum apparent diameter as seen from the planet: 0" .01? Planet composition Jupiter is the largest planet in the solar system. By comparison, Jupiter's volume is 1,330 times greater than Earth, and its mass is 318 times greater. Mass of Jupiter, in fact, accounts for two-thirds of the total mass of all the planets combined. Jupiter's low density suggests that planet is composed of light elements; in particular hydrogen and helium in gas and liquid form. The planet's center is thought to be a small (10 to 20 Earth masses) rocky core of iron and silicates, surrounded by liquid or solid hydrogen. About 1,000 km from the visible surface, researchers believe there is a transition zone from gaseous to liquid hydrogen, where the temperature is about 3,141░ F / 1,727░ C / 2,000░ K and the pressure about 5,600 atm. At 3,000 km below the clouds, the temperature is about 9,451░ F / 5,263░ C / 5,500░ K and the pressure is 90,000 atm. At 25,000 km below the cloud tops, the temperature is over 19,341░ F / 10,727░ C / 11,000░ K and the pressure is about 3,000,000 atm. At this point, hydrogen changes from liquid molecular to liquid metallic hydrogen. Maximum temperatures reach 53,541░ F / 29, 727░ C / 30,000░ K and 100 million atm at the core. [Rick: here are the composition figures we came up with. You may want to compare them to your own.] Crust = 500 km Mantle = 13,500 - 14,500 Core = 46,000 km Topography The most prominent "topographical" feature is the Great Red Spot (16,280 x 8,575 miles). Located in atmosphere over the southern hemisphere, this hurricane-like storm is more than twice the size of Earth. It was perhaps first seen and documented by Robert Hooke in 1664, but researchers believe it may be millions of years old. The Great Red Spot is much colder than its surroundings, with temperatures averaging -202░F. As a high-pressure region, the Great Red Spot spins the opposite direction of low-pressure storms on Jupiter. Atmosphere Jupiter's atmosphere is largely hydrogen (<90%) and helium (<10%). Ammonia, methane, ethane, acetylene, water vapor, phosphine, carbon monoxide, germane, and tetrahydride also present in small quantities. By comparison, the basic structure of Jupiter's atmosphere resembles Earth's tropospheric levels. The Jovian magnetosphere is thought to be about 100 times as strong as Earth's and to have areas similar to our Van Allen Belts. The size of Jupiter's magnetosphere changes in response to interaction the solar wind. The collision with solar wind particles forms a shock wave (called a bow shock), within which there is a turbulent region known as a Magnetopause. In this region, Voyager measured temperatures of 602 - 751 million ░F / 300-400 million ░C / 300-400 million ░Kùthe highest found in the solar system. The atmosphere surrounding Jupiter contains dark streaks (known as cloud belts) and bright bands (known as cloud zones). Several of each variety are relatively stable, changing only slightly in latitude. Some occasionally disappear. Ammonia crystals form white clouds in Jupiter's atmosphere, while sulfur compounds (and perhaps phosphorus) produce the brown and orange hues typically associated with Jupiter's appearance. Magnetic fields and gravity Researchers believe that Jupiter's magnetic field is generated by a dynamo. The electrical conductor is believed to be liquid hydrogen at or near the planet's core, but the force driving the system is unknown. (Researchers speculate that it involves planetary rotation.) The magnetic field on Jupiter is inclined to the planet's axis of rotation by an angle of about 11░ (as compared to 10░ on Earth), and the alignment of the magnetic poles is such that a compass needle would point south. On Jupiter, the surface gravity is 2.69. Orbit and rotation Jupiter has an elliptical orbit that takes 4,332.59 days (11.86 years) to complete. Because it is mostly fluid, Jupiter's period of rotation varies with latitude, the fastest rotation being at the equator (9 hours 50 minutes 30 seconds). This fast rotation causes a bulge to form, making the planet's equatorial diameter about 142,800 km, while its polar diameter is only 132,400 km. Moons (and/or rings) Jupiter has 16 known satellites. The four largestùIo, Europa, Ganymede, and Callistoùare known collectively as the Galileans in honor of the first observer, Galileao Galilei on 7 January 1610. All the Galileans have a synchronous rotation (they orbit Jupiter in the same amount of time it takes to rotate on their axes) and all are the size of planets. Of note, Io has nine active volcanoes, the only such volcanoes known in the solar system (except on Earth). Jupiter is also surrounded by rings, which consist of several segments and seem to extend to the planet's surface. Researchers believe that the are made up of relatively high-density rocks (dust), as opposed to the icy material found in Saturn's rings. They also believe the rings originated from the gravitational break-up of a tiny inner satellites, plus materials from other satellites, comets, and meteorites. Mythology Jupiter was named for the ruler of Olympus. Amalthea was named for the one who suckled Zeus (Greek for Jupiter) as a young child. Io was named for the daughter of Inachus. Europa was named for the beautiful daughter of Agenor, king of Tyhre. Ganymede was named for a beautiful young boy who, after being carried to Olympus by Zeus, became cup bearer of the Olympian gods. Callisto was named for the beautiful daughter of Lycaon. Discovery and exploration In 1972, NASA sent the first of four spacecraft slated to conduct the initial surveys. Pioneer 10 lifted off in March 1972 and returned the first close-up images of Jupiter in December 1973, flying within 132,252 km (82,178 miles) of the cloud tops. Pioneer 11 followed 1 year later. Voyagers 1 and 2 were launched in the summer of 1977 and did flybys in 1979. A new mission to Jupiter, known as the Galileo project, is under way. On December 7, 1995, the orbiter will spend two years circling the planet and flying close to the large moons. It will also drop an atmospheric probe into the cloud layers to relay information back to Earth. [Rick: We didn't find any information here related to early belief in life forms.]
