Giant Jupiter.

Jupiter Diametr 142 800 km Mass 1,9*10^27 kg Density 1330 кг/м^3 The period of rotation 9 h 55 min 29 sec The average distance from the Sun 5,20 а.u. The period of revolution 11,86 years Excentricity of the orbit 0,048 The orbit's slope 1,3њ

Lupiter is the fifth from the Sun big planet of the Solar system. It is the biggest planet from the giant planets. The equator is bent to the orbit plane at the angle of 3њ 5' and the seasonable changes are not very significant. It is seen as a yellow star - 2,6 of a star value.

Jupiter has no solid surface that is why speaking about its dimensious point the radius of the upper border line of the clouds, where the presseru is about 10 KPa; radius of Jupiter on the equator is 71400 km. Its equatorial zone rotates 9 h 50 m 30 sec, i.e. 5 m 11 sec less of the rotation period of its pole zones. Free fall acceleration on the equator is 23,5 m/s?.

The rotation of the Big Red Spot of Jupiter is the slowest. During one hundred years it makes about three turning. The nature of this phenomenom is not clear yet.

The structure and composition of Jupiter.

As other giant planets Jupiter differs greatly from the terrestrial group planets by its chemical composition. Absolutely dominating here is hydrogen and helium in the solar ration 3,4:1. But in the centre of the planet, according to the modern theories there is a liquid core of the molten metals and silicates, surrounded by the water-ammonia liquid shell. The radius of Jupiter core is 1/10 of the planet's radius, the mass is 0,3 - 0,4 of its mass, the temperature is about 2500 K and the pressure is about 8000 GPa

The physical and the chemical parameters.

The reddish colour of the planet is due to the phosphorus presense in the atmosphere and perhaps to the organics appearing after the electric charges. The pressure is about 100 KPa, the temperature is 160 K. It is true that there are clouds on different heights.

There are thunderstorms in Jupiter atmosphere. The ionosphere extent is about 3000 km in the height.

Jupiter has a magnetic field. Its magnetic dipole moments is 12 000 time more than the terristrial one. Jupiter also possesses a magnitosphere similar to the terristrial, but 100 times greater. There are also radiation zones.

The Jupiter satellites.

The first four Satellites were discovered by Galilei in 1610. This discovery was the push to development of the heliocentric system of the universe by Copernic. Nowadays 16 satellites of the Jupiter are known: Adrastea, Mitis, Amaltea, Phina,then 4 Galilei satellites: Io, Europe, Hanimed, Callisto, Leda, Aimalia, Zicitea, Elara, Ananke, Carme, Pasipe and Sinope. They are called by the names of the Jupiter lovers.

The most Jupiter satellites were discovered only after the spaceship's flights of "Pioneer" (1973-1974) and later of "Voyager" (1977).

The first from Galilei's satellites Io is greater than the Moon. It has an atmosphere and ionosphere mainly consisting of sulphur and natrium ions. Its volcanic activity is very high (more than in the Earth). The volcanic craters are the hundred kilometers long, exceeding the terrestrial ones in tens and even hundred times, though the volcanic height is not so great. Only in the Pole zones of Io there are volcanos of 10 km height. The sulphur from the volcanos arise in 250 km height. According to the opinion of some investigators the liquid sulphur may be under the thin hard external crust of the satellite, covered by the layer of sujphur and its dioxide. The temperature near the Io surface is about -120њC in the equator (except the volcanic areas) and even 50њ below than this at the Poles. The relative fewness of the percussion craters more than 1 - 2 km allows to consider the surface of Io to be comparatively young (less than 1 billion years).

There even less craters exceeding 5 km in diameter on the Europe surface. The Jupiter satellites densities are decreasing with their orbits radiuses increasing. Unlike Io, the other satellites surfaces are covered with ice including the water ice, a proportianal part of which decreases with the remoting from Jupiter: the farther from Jupiter the more a proportional part of it. The supposition about the icy crust under which may be a comparatively crumbly layer of a "spongy" ice, saturated with water, may explain the observed peculiarities of some satellites, for example a comparative smoothness of the surface and a high reflecting ability. So Europe's reflecting ability is great and a difference of the heights is only about 10 meter. Besides there are no craters more than 10 km in diameter in Europe but there are a lot of long (200 - 300 km) non deep furrows, which is connected with the peculiarities of the surface shelter. It is worth mentioning that the heights' differences on Hanimed (radius of which is 500 km more than Mercury radius) and Callisto are more than in Europe.

But not all of Jupiter satellites have smooth surfaces. So the craters compactness in some regions of Callisto, being lees than Hanimed is near maximum. In some regions the craters edges are connected. One of the causes of such location of craters is may be the fusible soils (for example, ice).

There is a giant flat ring made of the dust, small stones. The width is 6 km, the thickness is 1 km and the height is about ten thousand kilometres from the upper border of the clouds.

Jupiter and its satellites investigation, had given many bew results already, led to the arising of some new problems. Particulaly they are only in the process of investigating the problems concerning the physical nature of the intensive electric fields of the nearest to Jupiter satellites.