Jupiter

Jupiter, the fifth planet from the sun, is the largest planet in our solar system. The planet was named after the supreme deity of the Roman gods.

Jupiter's diameter at the equator is about 88,700 miles (142,700 kilometers), which is more than 11 times the diameter of Earth. It would take 1,000 earths to fill up Jupiter.

Jupiter's average distance from the sun is about 483 1/2 million miles (778 million kilometers). Jupiter is about 391 million miles (629 million kilometers) away from earth at its closest approach.

Jupiter goes around the sun in an elliptical (oval shaped) orbit. At its farthest distance, Jupiter is about 507 million miles (816 million kilometers) away from the sun. At its closest approach, Jupiter is 460 million miles (740 million kilometers) away from the sun.

One year on Jupiter takes about 4,333 earth days, or almost 12 earth years. Jupiter has 16 known satellites. The four biggest of these moons are called Galilean satellites because the Italian astronomer Galileo discovered them in 1610. These four moons all have diameters greater than 1,900 miles (3,060 kilometers). Two of the moons, Callisto and Ganymede, appear to be composed of the same amount of rocky material and ice. The other two, Europa and Io, consist of rocky matter with little or no ice. Io has active volcanoes. Jupiter's 12 other satellites have diameters that range from about 9 miles (15 kilometers) to 106 miles (170 kilometers). These satellites were discovered with the use of powerful telescopes and space probes.
It has been discovered that there is a little ring around Jupiter consisting mostly of fine dust particles. This ring is much fainter than the bright rings around Saturn. This ring is estimated to be about 18 miles (29 kilometers) thick and more than 4,000 miles (6,400 kilometers) wide.

The surface of Jupiter can't be seen from the earth because it is covered by layers of dense clouds. These high level clouds are thought to consist of frozen crystals of ammonia and methane. Most of today's astronomers believe that Jupiter is a fluid planet, consisting primarily of gas, with some liquid as well. The planet may also have a small solid core of rocky material.
As viewed from earth with a telescope, it can be seen that Jupiter has a series of colored belts and zones in its clouds. The belts are dark lines that circle the planet parallel to its equator. The widths and positions of the belts change slowly throughout the years. The zones are light-colored areas between the belts. The belts and zones are thought to be caused by various gases in the clouds.

A large, oval mark called the Great Red Spot can also be seen on Jupiter's clouds. This Great Spot is about 25,000 miles (40,200 kilometers) long- more than three times the diameter of earth- and is about 20,000 miles (32,000 kilometers) wide. From year to year this spot slowly changes its position. Most astronomers believe the spot is an intense atmospheric disturbance that may resemble a hurricane. It seems that it consists of violently swirling masses of gas.
Jupiter's atmosphere is composed of about 84 per cent hydrogen and about 15 percent per cent helium. It also includes small amounts of acetylene, ammonia, ethane, methane, phosphine, and water vapor.

Fact Sheet
Planet Name		Jupiter
Latin Name/Greek Name		Jupiter/Zeus
Symbol
Year Discovered/Discoverer		N/A
Mass		1,898.7 x 10²⁷ g
Volume (Earth = 1)		1316
Density		1.33 gm/cm³
Surface Gravity		2312 cm/s²
Escape Velocity at Equator		59.54 km/s
Mean Equatorial Radius		71,492 km
Albedo (Percentage of light reflected)		.52
Motion
	Sidereal Rotation Period (Earth Days)	0.41354
	Rotation Direction	Direct
Orbit
	Sidereal Orbit Period (Earth Years)	11.85652502
	Mean Orbit Velocity	13.0697 km/s
	Orbit Eccentricity	0.04839266
	Mean Distance (Semimajor Axis) from Sun	778,412,010 km
	Inclination of Orbit to Ecliptic	1.30530 degrees
	Inclination of Equator to Orbit	3.12 degrees
Natural Satellites		Metis Adrastea Amalthea Thebe Io Europa Ganymede Callisto Leda Himalia Lysithea Elara Ananke Carme Pasiphae Sinope

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