Water on Mars
OMEGA observed the southern polar cap of Mars on 18 January 2004, as seen on all three bands. The right one represents the visible image, the middle one the CO2 (carbon dioxide) ice and the left one the H2O (water) ice.
This image from the Mars Orbiter Camera clearly shows large contraction-crack polygons which may have developed as a result of the repeated seasonal or episodic melting, freezing and movement of water in an active layer overlying an ice-rich permafrost zone. (The scale bar is 200 m.)