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Planetary Science 2014 – Part 4
The Tiger Stripes in the southern region of Enceladus are produced by the gravity from
Saturn. The resulting tidal forces cause large areas of the surface to push together or pull
apart or slide along each other. This causes the material beneath the surface to heat due
to the tidal stresses, and the resulting flexing on the moon allows geysers to form and eject
materials from beneath the surface of Enceladus. The orbital position graph shows the resulting
change in elevation due to the fault-parallel and vertical displacements. Look at different
types of diagrams and graphs and charts that result in the movement of water. Do not study
just one or two types of charts or illustrations as several different types may be used in
the interpretive tasks. Iapetus is the third largest satellite of
Saturn and has both dark areas and bright areas. It is locked in synchronous rotation
with Saturn and orbits very slowly. It is surrounded by other moons of Saturn. It is
thought that the dust and debris from the other moons settle onto the surface of Iapetus
in the equatorial regions. When radiation reaches this part of the surface, the ice
sublimates leaving behind the dust. The ices then condense towards the polar regions. The
dark regions keep getting darker as more and more dust accumulates, and the light regions
keep getting brighter as more and more ices condense in those area. Iapetus also has a
bizarre ridge that circles the moon which I will talk about on the next slide.
This is part of the transitional zone between the bright ice regions and the dark dusty
regions. Study this zone to understand where materials are sublimating and where they are
condensing. This is the ridge that circles Iapetus – called
The Wall. Iapetus used to rotate faster and had a more oblate shape with the diameter
wider in the equatorial region, similar to the shape of Earth. One possibility is that
The Wall is the result of surface material forming as the moon rotated slower and slower.
One other possibility is that Iapetus used to have its own ring and the ring material
collapsed onto the surface of the moon. Titan is the largest moon of Saturn and is
known for being the only moon in the Solar System with a thick atmosphere. The atmosphere
is composed of hydrocarbons. This graphic illustrates the possible underlying
structure of Titan, showing a global subsurface hydrocarbon ocean sandwiched between a de-coupled
icy shell and high pressure ice above a hydrous silicate core.
This is an artist illustration of the surface and atmosphere of Titan. It is thought that
on the surface methane exists at its triple point. On Earth water exists at its triple
point – all three phases of liquid, gas, and solid. On Titan methane displays the same
property, so Titan has methane clouds, methane rain, methane lakes, and methane ice and oceans.
We know what the surface of Titan actually looks like as the Cassini mission deployed the Huygens probe into the
atmosphere and captured images until it stopped functioning.
This is an actual raw image of the Titan surface taken by the Huygens probe and it shows the
remnants of channel edges and drainage channels and patterns. These images show that large
amounts of liquids have moved across the surface of Titan in the past.
This is an elevation map of Titan assembled from several images captured by the probe.
It shows the topography and elevation of the moon. Make sure to research and put together
images similar to this for all of the features and objects that are listed in the event description.
An archive of different types of graphs, charts and data are important resources for this
event.