JupiterJupiter is the fifth planet in order of distance from the Sun and the first one for dimensions.

The data collected by the probes Voyager 1 and 2, as well as, in more recent times, by the probe Galileo and by the telescope Hubble, revealed that the Jupiter's atmosphere, whose thickness is esteemed around 1.000 km, is shaken by continuous turbulent motions: the visible surface of the planet is the top of such atmosphere. It is composed by hydrogen (85%) and helium (15%), with traces of methane, ammonia, water and sulphur. The solar heat and the heat emanated by the inside of the planet, which radiates a quantity of energy equal to twice and half of that one received by the Sun, prime in the atmosphere great connective movements, with formation of clouds that, bacause of the high speed of rotation, put themselves along bands parallel to equator. The regular disposition of these bands is interrupted by cyclonic perturbations, the greatest of which is the Big red spot, wide for 30-40.000 km in longitude and 13.000 km in latitude.

Theoretical model show that at a depth of 1.000 km the pressure forces the hydrogen to pass in liquid state; and at 24.000 km the hydrogen would become solid. At a depth of 60.000 km, there would be, finally, a nucleus of rocks and heavy metals.

The probes discovered the existence of a ring of solid particles on the equatorial plan and a magnetic field, which is 4.000 times more intense of the terrestrial one and is extended up to a distance of 8 millions of km.

Jupiter is the center of a system of sixteen satellites.

Average distance
from the Sun
778.300.000 km
Longest distance
from the Sun
815.700.000 km
Shortest distance
from the Sun
740.900.000 km
Period of revolution11,86 years
Period of rotation9 hours, 50' 30''
orbital velocity
13,1 km/s
Inclination of the axis3° 05'
Inclination of the orbit
compared to the ecliptic
of the orbit
Equatorial ray71.400 km
Mass1,9 x 10^27 kg
Density1,3 kg/dm³

Jupiter's satellites

distance (km)
period (days)
Author and year
of discovery
Metis128.000200,37Voyager 1, 1979
Adrastea128.500< 50,37Voyager 1, 1979
Amaltea181.3001200,50Barnard, 1892
Tebe221.500400,66Voyager 1, 1979
Io421.50018201,77Galilei, 1610
Europa670.50015303,55Galilei, 1610
Ganimede1.070.00026357,15Galilei, 1610
Callisto1.880.000245016,69Galilei, 1610
Leda11.110.0005240,00Kowal, 1974
Imalia11.470.00085250,00Perrine, 1904
Elara11.730.00040260,00Perrine, 1905
Lisitea11.750.00012261,00Nicholson, 1938
Ananke20.700.00010670,00Nicholson, 1951
Carme22.350.00015692,00Nicholson, 1938
Pasifae23.300.00020737,00Melotte, 1908
Sinope23.650.00015758,00Nicholson, 1914

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