Jupiter
Jupiter is the largest planet in the Solar System. So it was named after the ruler of all Greek-Roman Gods, Jupiter. This gas giant is the fifth planet from the Sun. The diameter of Jupiter is eleven times that of the Earth. It is the most massive planet of about 318 times as that of the Earth. But it has a low density. Jupiter consists of a small rocky core covered with an inner mantle of metallic hydrogen. The outer mantle contains liquid hydrogen, helium and traces of some other metals. Jupiter is the fastest rotating planet to take nearly 10 hours to complete one rotation. The speed of rotation is very high so that belts and zones are formed from the clouds and they surround the planet parallel to the equator. Dark warm cloud layers are called belts and bright cooler cloud layers are called zones. Due to the irregular flow of the fluids the clouds unite at some regions and form storm systems like Red Spots and White Ovals. The most distinctive storm thus formed is the Great Red Spot which rises about eight kilometres from the upper layer of clouds. Jupiter has a thin, faint ring consisting of tiny dust particles. Among the 16 known satellites of Jupiter, the largest four are
Ganymede, Callisto, lo, and Europa. Ganymede is the largest satellite in the Solar System. Ganymede and Callisto have cratered rocky surface with ice. lo has active volcanoes containing sulphurous materials which appear as red, orange and yellow spots. The icy, smooth Europa shows traces of water contents.
Spacecrafts to Jupiter
The first spacecraft to fly past Jupiter was Pioneer-10 launched by the United States in 1972. It measured the amount of hydrogen and helium in Jupiter's atmosphere, and the radiation belt. It also found that Jupiter has an extra large magnetic tail. Pioneer-Saturn, another US spacecraft sent on December 2, 1974 took close-up photographs of Jupiter. Voyager-I launched in March 1979 by the US discovered the thin ring which encircles the planet. Voyager 2, in July 1979 sent detailed pictures of the four main satellites of Jupiter towards the Earth.
Jupiter
Distance from the sun in km.: 778.4 million
Diameter at equator in km.: 142,984
Mass with respect to the earth: 317.892 (earth=1)
Gravity with respect to the earth: 2.53
Period of revolution: 12 earth years
Period of rotation: 9 hours and 55 minutes
Density (g/cm³): 1.33
Temperature: -157°C
Satellites: 63
