Melting Ice on Mars?
These Mars Reconnaissance Orbiter images show in increasing magnification a puzzling feature in the southeast part of a ice mound in Louth Crater on Mars. Located at 70 degrees north latitude, this is the farthest south that scientists have found permanent water ice. The close-up image suggests melting ice with the draining water running down hill to the south, though on Mars the low air pressure would cause any liquid water to evaporate instantly. Key quote:
These may be the crests of partially defrosted dark sand dunes or perhaps some other feature that we do not understand. This is the only area on Louth where these enigmatic ridges are found.



