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.