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IO: 
Io is the most volcanic moon in the
Solar System. It has many different surfaces including volcanic craters,
lakes of molten sulfur, mountains, and lava flows. Some spots may reach
1,000 degrees Fahrenheit. When viewed by the Voyager, there were 9
erupting volcanoes all concentrated towards the equator. A detection of
water ice or even steam on Io was not found. There were spectral lines
of double ionized sulfur. Sulfur was abundant on the surface and because
of this the surface of Io, seems white. It is slightly larger than our
moon and orbits Jupiter every 1.75 days at a distance of 262,000 miles.
As Io orbits Jupiter, the planet's gravity stretches Io slightly. This
heats the moon's inner rock, causing the rock to melt and explode in
eruptions that shoot gas and sulfur in to the sky.
EUROPA: ADRASTEA: AMALTHEA: ANANKE: |
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Europa is the smallest of the
Galilean moons. It is about 1,942 miles across and 417,000 miles from
Jupiter. It completes one orbital every three and a half days. The
surface is covered with ice. From a distance, it looks like a smooth,
white ball. Compared to our moon, Europa is much brighter with a 64
percent reflectivity compared to the moon's seven percent. The ground
based infrared spectra has shown that there is a lot of water ice
present on the surface. Europa is covered with brown tinted ice.
Scientists believe that more ice or water may like beneath the icy
crust. A detailed inspection has shown that there are fewer than twelve
circular craters that have been formed from meteoric impacts. This
information leads to the belief that Europa's surface is mobile and can
erase all but the most recent impacts. There are several types of
terrain on the surface. These include plains cut by grooves and ridges.
The mottled terrains are either brown or gray, The brown tint is due to
angular structures and vertical ridges. The gray regions show less
distinction. There are many linear grooves and macula (brown regions).
This satellite consists of a rock core covered by a crust of ice.
Fractures that have formed may be the result of tidal stresses.
This satellite was discovered in 1892. It
is 181,300 km away from Jupiter. Amalthea's period of revolution is
0.498 days and has a 0.4 degree of inclination. Its eccentricity is 0 as
well. Almathea's orbit of Jupiter takes about twelve hours. It is an
irregular ellipsoidal satellite with a cratered surface. It is aligned
with Jupiter's shortest axis and the axis of rotation is perpendicular
to the plane of the orbit or Jupiter's equator. Amalthea's diameter is
270 km along the longest axis and 155 km along the shortest axis. This
moon is the largest among the four inner moons. There may be sulfur rich
material on Amalthea because it's reflectivity is very low and its color
is a dark red. 
