Jupiter

JUPITER

NAME
Supreme God (Greek: Zeus)
ABOUT JUPITER
Jupiter is the largest planet and the first of the outer 'Gas
Giants'. It consists almost entirely of Hydrogen and Helium
like our sun. It would need to be at least 80 times more
massive for it to begin thermonuclear 'burning' like our Sun.
The pressure from the higher gravity starts the reaction. It is
not certain if it has a solid surface or where it would begin.
Heavier elements sink to the core so there must be a 'surface'
at some point.

The most famous Jovian feature is it's 'Great Red Spot'.
It's a storm much like a terrestrial hurricane. The Red
Spot has persisted since early telescopic observations (1660's).
We don't know how long it existed in prior centuries.

In 1994 comet Shoemaker-Levy 9 crashed piece by piece into
giant Jupiter leaving huge black marks. Recently some old
drawings of Jupiter have been found showing similar marks.
Could other comets have crashed into jupiter? It seems likely.
Jupiter's powerful gravity disrupts the orbits of incoming
comets.
DISCOVERY DATE
Antiquity
MOONS
Sixty-three as of 7/23/06. The four largest are big enough to be worlds
themselves. They are called the Galilean Moons because
Galileo discovered them in 1610 when he turned the newly
invented telescope to the heavens. There is also a faint ring
discovered by the voyager spacecraft.

Io - a world being constantly turned inside out. Jupiter's
gravity is always pushing and pulling on it causing great
internal heat. The heat is released in constant volcanic
activity.

Europa - a moon with quite possibly a liquid ocean. It's
surface is a very thick ice. Like Io it's flexing by Jupiter's
gravity causing enough internal heat to melt the ice
underneath the surface forming an ocean. Being further
out than Io, it doesn't generate as much heat so there are no
volcanos.

Ganymede - is the largest moon in the solar system with a
varied surface of light and dark patches, craters and
grooves. The grooves are likely caused by some sort of
tectonic activity. It is actually larger than the planets
Mercury and Pluto.

Callisto - is the most cratered body in the solar system.
This suggests that it is dead geologically and it's surface
must undergo few changes over geologic time scales.
OBSERVING-NAKED EYE
Jupiter is brighter than all the stars in the sky. It tends
to look sort of yellowish to me. An interesting challenge
is to try and spot one of it's moons. When the planet is
high in the sky, block it's light with a chimney or other
such object and see if you can spot a very faint glimmer
of light in close proximity to the planet. It is a very
difficult observation. Use binoculars to give you an
idea of what to look for.
OBSERVING-TELESCOPE
Jupiter may possess the most observable detail in a small
telescope. Even the very smallest will show the four
Galilean moons and two bands of reddish light crossing
the planet's disk. The moons can be followed from night
to night. Sometimes the moons can be seen crossing the
disk (transit) or passing behind the planet (occultation).
In a moderately sized scope one can see many bands of
light that make up the planet's atmospheric currents.
Much detail can be seen in the bands. The Great Red Spot
can be seen as well.

A computer simulation. It depicts Jupiter as seen from it's moon Europa. It shows Jupiter's Great Red Spot. The moon passing across Jupiter is Io the innermost large moon. This is similar to what can be seen in a large amateur telescope. Io however, can not be seen in such detail. the view is from Europa, not earth, distorting Io's apparent size. Jupiter's faint ring is also seen crossing the disk. There are also some background stars.

Callisto - to the right is Valhalla basin, a large impact crater.
The bright patches are craters. 'Meteor hits' expose fresh ice
under the darker surface material creating bright patches.

Europa - showing cracks in it's icy smooth surface. Recent Galileo spacecraft images suggest an ocean beneath the ice.

Ganymede - largest moon in the solar system.

Io - volcano tortured world. One volcano can be seen erupting on the horizon.

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