Mac Glidewell
AST 191
Activity 6
In activity six we are using the same approach that we used in activity five. In this
activity we are going to look at the Galilean Moons and examine the geologic activity of
each. From activity five we learned that there is a strong correlation between planet/moon
radius and geologic activity; the larger the radius, the more geologic activity there will
be. Because of these findings, I would guess that there would not be much geologic
activity on the Galilean Moons. If there is, the most activity should take place on
Ganymede and Callisto.
On the first Galilean Moon of Io, one can easily notice that there are a number of
craters. The craters seem to be very spread out over the moon, the craters do not appear to
be too dense in any one area. Also from the pictures we can notice some open fissures
that exist on the moon. This is an obvious sign that the moon is still geologically active. I
would give Io a ranking of four because of the open fissures on the planet.
On the moon of Europa there are very few craters that are noticeable. In fact,
there are only two that immediately stick out when looking at the picture. The moon has
many brown lines that stretch all around it, but the lines seem to be concentrated in the
middle. The part of the moon that is not covered by the brown lines is an ivory color. I
would give Europa a ranking of three because it only has two craters (which shows it is
very active) but does not have open fissures like Io.
The moon of Ganymede has a mostly purple and blue hue to it. It appears to have
many craters that are scattered around, but the craters appear to be white (potentially
because of ice). In closer images of the moon, it is possible to see how the ice has giant
cracks in it that run for miles. I would give Ganymede a ranking of two because it looks
like it has mostly ice, but does not have as many craters as Callisto.
The moon Callisto looks much like Ganymede. Callisto also has a purplish-blue
hue to it, as well as the white craters. But on Callisto, there appears to be many more
craters than there are on Callisto. Especially in the middle of the moon, there is a giant
crater. Callisto by far has the most craters and is covered in ice, there for it gets a ranking
of one.
When looking at the Galilean Moons it seems that radius was once again a factor.
The largest moon was Io and was definitely the most geologically active. Callisto was
one of the smaller moons and was least active when compared to the others.
The single most important parameter when examining the geologic activity of a
planet or moon, is the radius of the object. A possible reason that this is the case, could be
that it is easier for larger planets and moons to sustain geologic activity. When a planet or
moon is large, it may take longer for all geologic activity to subside. This is because there
is simply more geologic activity going on.