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Planetary Science 2014 – Part 2
The United States Geological Survey (USGS) has topographic maps of the surface of Mars
available. We have been watching Mars for a long time and Mars is fascinating for several
reasons. It is in the habitable zone of the Sun just like Earth; however, conditions went
wrong and we would like to know if Mars supported life at some point in its past. We have watched
Mars through telescopes, and sent a lot of spacecraft to orbit and land on Mars. We have
studied the ice caps and their seasonal changes involved with the sublimation of carbon dioxide
as Mars orbits the Sun on its tilted axis. The European Space Agency sent the Mars Express
mission in 2003 during the northern polar cap summer solstice transition. This mission
is an example of how instruments are used to remote sense conditions on planetary surfaces
to provide information about the location and movement of water. The infrared spectrometer (OMEGA) observed phyllosilicates
that gave evidence of copious amount of water movement in the past, and the camera (HRSC)
showed that volcanism is much more recent than previously thought – during the past 100 million years. The
spectrometer (PFS) discovered changing amounts of methane in the atmosphere which is an indication
that there may still be active subsurface volcanism on Mars.
The Mars Odyssey Mission was sent to the south polar ice cap and collected information during
the spring thaw. The Thermal Emission Imaging System (THEMIS) observed sand jets that appear
when the carbon dioxide sublimates. The dust which is frozen into the carbon dioxide is
then ejected into the atmosphere as plumes and then settles down onto the surface. The
length and direction of the dust plumes on the surface are used to determine the wind
direction and velocity. There is evidence of massive amounts of underground
water locked into equatorial glaciers. This glacial feature is on planet Earth and shows
the landform features caused by moving glaciers. This landform is very similar to the feature
on the right on the surface of Mars. This landform feature is caused by the movement
of the equatorial glaciers below the Martian surface. Estimates are that these equatorial
glaciers are 800 meters deep. The Phoenix Mission landed in the vicinity
of the extreme edge of the polar ice cap. The mission studied polygon features similar
to those produced here on Earth from the seasonal melting and freezing of subsurface water in the Tundra regions.
These seasonal changes produce distinctive polygon shaped hummocks.