The image that we propose you for today's APOD comes from NASA's - Mars Reconnaissance Orbiter (MRO) and shows us a variety of Surface Textures within the South Polar Residual Cap of Mars. The picture was taken during the Martian Southern Spring, such as when the Surface of the Red Planet was covered by seasonal Carbon Dioxide (CO2) Frost, and when the Sun was very low on the Local Horizon (4° only), so that each and every Surface Relief (even the smallest ones) could easily be seen.

Illumination is coming from the bottom part of the frame, thus highlighting long Troughs and Round Pits (as well as the so-called Swiss-cheese Terrain) with Irregular Mesas. These unique Landforms are common in the South Polar Residual Cap, which is known - from previous NASA - Mars Global Surveyor Orbiter images - to be eroding quite rapidly, but only (and apparently) in certain specific places.

Right of center, South Polar Layered Deposits (or SPLDs for short) are exposed on a Sun-facing Scarp. These SPLDs are older than the Residual Ice Cap, and the Layers which form them are thought to record the Climate Variations on Mars in a similar (likely identical) way that both the North and South Polar Layers existing on our Home Planet record the Ice Ages which occurred on Earth.

 

Mars Local Time: 22:14 (Late Evening Hours)
Coord. (centered): 87,2° South Lat. and 340,3° East Long.
Spacecraft altitude: 244,7 Km (such as about 152,9 miles)
Original image scale range: 24,5 cm/pixel (with 1 x 1 binning) so objects ~ 73 cm across are resolved
Map projected scale: 25 cm/pixel
Map projection: POLAR STEREOGRAPHIC
Emission Angle: 0,0° (meaning the the Spacecraft was absolutely perpendicular to the Surface that was being photographed)
Phase Angle: 85,8°
Solar Incidence Angle: 86° (meaning that the Sun was about 4° above the Local Horizon at the time that the picture was taken)
Solar Longitude: 195,7° (Northern Fall)
Credits: NASA/JPL/University of Arizona

 

This frame has been colorized in Absolute Natural Colors by (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Mars Reconnaissance Orbiter and then looked down, towards the South Polar Region of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.