Radar’s icy echoes on Mars
In order to measure the thickness of the southern ice sheet, the radar instrument sends invisible signals toward the surface and records the echoes. In this way, the radar is able to ‘see’ through the layers to the bottom of the ice. More than 300 of these ‘slices’ have been made through the deposits of ice and dust that cover the pole.
Ongoing radar studies of the north polar cap have shown that it is about 1.8 km thick. The thin layers of water ice and dust at both poles seem to be caused by seasonal and long-term changes in the climate. Although the polar caps hold most of the known water on modern Mars, other places on the planet may have been wet enough to support life in the distant past.
Last update: 18 April 2011