Jupiter is the largest planet of our solar system, at a distance of 5 A.U. from the Sun and revolves around it once every 12 years. It alone contains two-thirds of the mass in the Solar System outside of the Sun, 318 as much as the Earth. It is 11 times greater in diameter than the Earth and Its density is estimated to be 1.3 g/cm3.

Jupiter has many moons. Observations with a small telescope show four of its moons (Io, Europa, Ganymede and Calisto, discovered by Galileo in 1610) and reveal bands of clouds across its surface. Ganymede, at 5,276 km in diameter, is the largest satellite in the solar system and is larger than the planet Mercury. Some of Jupiter's moons revolve in the direction opposite from that of Jupiter's rotation (that is, retrograde), while other moons revolve prograde.

Jupiter and Io (photo by Cassini probe)

Jupiter chemical composition is almost entirely hydrogen and helium and, therefore, is closer to that of the Sun and stars than it is to that of the Earth. In Jupiter's outer parts, most of the hydrogen is in the form of hydrogen molecules (H2).Jupiter isn't solid, it has no crystal surface at all. At deeper and deeper levels, its gas gets denser and denser, eventually liquefying.

The most prominent feature of the visible cloud surface of Jupiter is a large reddish oval known as the Great Red Spot (GRS). It is about 13,000 km x 26,000 km, larger than the Earth, and drifts about slowly with respect to the clouds as the planet rotates. The GRS is a relatively stable feature, for it has been visible for over 350 years. It is an anticyclonic storm, because its center has high pressure,  with counterclockwise winds.

Jupiter rotates very quickly, once every 10 hours. Its rapid spin is a major reason for the colorful bands, which are clouds spread out parallel to the equator. They are in constant turmoil; the shapes and distribution of bands change in a mater of days. Due to Jupiter's rapid rotation, the effect that we call the Coriolis force is particularly strong. Computer models show that under such conditions, large vortices like the GRS are produced. When many unequal spots are produced, the stronger ones absorb the weaker ones until only a single vortice is left. Such vortices last a long time.

Jupiter has bright bands called "zones" and dark bands called "belts". The zones are rising gas, while the belts are falling gas. The colors we see in the belts may have to do with sulfur compounds in the middle clouds, or perhaps with organic molecules.

In what many observers called the most exciting week ever in astronomy, pieces of periodic Comet Shoemaker-Levy 9, D/1993 F2, crashed into Jupiter in July 1994.

Observer's Log

Jupiter

Number of Frames: stack of 86 best frames out of 451

Exposure:  15 fps AVI

Equipment: LX200-12", F/20, Toucam Pro

Date: 03-03-28

Processed with K3CCDTools and Photoshop.

Jupiter

Number of Frames: stack of 133 best frames out of 669

Exposure:  5 fps AVI

Equipment: LX200-12", F/40, Toucam Pro

Date: 03-03-22

Processed with K3CCDTools and Photoshop.