Explanation:
What lies on the floor of this Martian crater?
A frozen patch of water ice.
The robotic
Mars Express spacecraft took the
above image in early February.
The ice pocket was found in a 35-kilometer
wide crater that resides 70 degrees north of the
Martian equator.
There, sunlight is blocked by the 300-meter tall
crater wall from vaporizing the water-ice on the
crater floor into the thin Martian atmosphere.
The ice pocket may be as deep as 200 meters thick.
Frost can be seen around the inner edge on the upper right part of the
crater, while part of the lower left
crater wall is bathed in sunlight.
The existence of water-ice pockets inside craters near the
Martian North Pole, like that
pictured above and
others noted previously, give clues not only about
surface conditions in the Martian past but also
possible places where future
water-based astronauts
might do well to land.
