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This artist's animation illustrates how NASA's Mars Reconnaissance Orbiter
used radar to map the insides of the north polar ice cap on Mars.
The animation begins by showing the orbiter flying above the Red Planet.
It then shows the orbiter shooting out beams of radio waves across a slice
of the ice cap. The waves, which belong to the radio portion of the
electromagnetic spectrum, penetrate through the ice and bounce back at
different times depending on the differing concentrations of sand and dust
in the ice.
The result is a glimpse inside the layers that make up the ice cap, as
demonstrated by the next part of the movie. The ice cap slices open to
reveal what the scientists found. Flashing green lights show some of the
actual radar reflections, subsequently seen as dark lines delineating the
layers. While the uppermost thin layers were observed before in camera
images, the deeper layers have been discovered by the Mars Reconnaissance
Orbiter. The movie ends by showing the radar image by itself.
These observations demonstrate that radar can be used to study the history
of global climate on Mars by revealing the patterns of deep layering. They
also expose a flat boundary between the ice cap and the surface of Mars,
indicating that the outer strong shell of Mars must be thick enough to
support the weight of the ice cap without sagging. This, in turn, suggests
that the planet's outer shell, called the lithosphere, is colder than
previously thought, with temperatures in the interior increasing gradually
with depth. Any bodies of liquid water that might exist underneath
Martian ground must therefore be deeper than previously calculated, where
temperatures are warmer.
This artist's animation is based on data from the Shallow Radar instrument
on Mars Reconnaissance Orbiter, as well as images from NASA's Mars Global
Surveyor mission.
The Shallow Radar instrument was provided by the Italian Space Agency. Its
operations are led by the University of Rome and its data are analyzed by
a joint U.S.-Italian science team. JPL, a division of the California
Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter
for the NASA Science Mission Directorate, Washington.
