Jupiter

Facts about Jupiter

A. Jupiter is named after the Roman king of the gods. It is more than twice as massive as all the other planets in the solar system combined.

B. Jupiter is a giant ball of hydrogen-based gasses, whose density is only slightly greater than water. Its surface features many alternating bands of clouds that spin in opposite directions. White bands are known as zones, dark bands are known as belts. They are caused by material rising from, and failing to, the interior of the planet. The risings and failings are due to convection currents within the planet. The Coriolis effect on the surface causes the winds to spin in opposite directions. Organic chemicals cause the color of the belts.

C. The Great Red Spot on Jupiter is caused by winds spinning in opposite directions on the surface - essentially a permanent hurricane.

D. Jupiter has no surface per se. As one descends through the clouds, they become increasingly dense. At a certain point, they are so dense, they are essentially liquid.

E. Jupiter gives off twice as much energy as it receives from the sun. This energy is probably residual heat from the formation of the planet.

F. Jupiter has 16 named moons. The four largest can be seen easily from Earth, and are known as the Galilean satellites.

1. lo is particularly interesting, as it is extremely volcanically active. The enormous gravitational field of Jupiter pulls and distorts Io to such an extent that internal friction heats up the moon. The internal heat manifests itself in volcanic activity, which produces sulfur, making the surface of the moon look reddish-orange.
2. Europa, the next moon out, contains an icy crust covering a mantle of liquid water. Some planetary scientists think that Europa might be able to harbor life. Its surface has recently been found to be covered with a great deal of Epsom salts.
3. Ganymede, the next moon, is the largest moon in the solar system, and is in fact larger than the planet Mercury.
4. Callisto, the last Galilean moon, is similar in composition to Ganymede, but not quite as large. The moons of Jupiter formed in such a way as to mimic the formation of the solar system. The small rocky moons formed towards the interior of the planetary nebula and the larger, lighter moons formed further out.
5. Circular No. 7998
   Central Bureau for Astronomical Telegrams
   INTERNATIONAL ASTRONOMICAL UNION
   
   SATELLITES OF JUPITER
    The IAU Working Group on Planetary System Nomenclature has
   approved the following new designations and names:
   
    Jupiter XVII    Callirrhoe  = S/1999 J 1
    Jupiter XVIII   Themisto    = S/1975 J 1  = S/2000 J 1
    Jupiter XIX     Magaclite   = S/2000 J 8
    Jupiter XX      Taygete     = S/2000 J 9
    Jupiter XXI     Chaldene    = S/2000 J 10
    Jupiter XXII    Harpalyke   = S/2000 J 5
    Jupiter XXIII   Kalyke      = S/2000 J 2
    Jupiter XXIV    Iocaste     = S/2000 J 3
    Jupiter XXV     Erinome     = S/2000 J 4
    Jupiter XXVI    Isonoe      = S/2000 J 6
    Jupiter XXVII   Praxidike   = S/2000 J 7
   
    (C) Copyright 2002 CBAT 2002 October 22  (7998) Daniel W. E. Green

G. Jupiter, as well as all of the Jovian planets, has rings. However, its rings are not as large or as visible as those of Saturn. The rings were not discovered until spacecraft were able to image the planet from behind so as to see the rings in relief.

H. Jupiter exhibits differential rotation, in which the equator of the planet spins faster than the north and south poles. Only a planet made essentially out of gas could do this. All of the Jovian planets exhibit this feature.

The supreme deity of the Romans, Jupiter is indeed the dominant planet in the solar system. A gaseous giant, Jupiter is far more massive and less dense that the small, rocky planets of the inner solar system. It's over 300 times the mass of earth and about two and half times the mass of all other planets put together.  No wonder Jupiter is referred to as "Guru" in Indian mythology. Also called Bhrispati, there are several temples in India dedicated to Jupiter. A majority of Indians observe fast on Thursday to seek the blessings of "Guru".

It's very easy to observe planet Jupiter. No wonder it was the first planet studied by Galileo. With the help of a standard telescope or a good pair of binoculars, the four Jovian moons and the belts of Jupiter can be easily visible. Keeping a nightly log of the position of the four satellites of Jupiter will be a rewarding experience. However, you will need a high power telescope to observe the red spot of Jupiter. Note that Jupiter rotates very fast, almost once ever 10 hours.

Manoj Pai, Ahmedabad, Gujurat, India

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