The Spiral North Pole of Mars

The Spiral North Pole of Mars

Image Credit:
ESA/DLR/FU Berlin;
NASA
MGS
MOLA Science Team

Explanation:
Why is there a spiral around the North Pole of Mars?

Each winter
this pole
develops a new outer layer about one meter thick composed of
carbon dioxide frozen out of the thin Martian atmosphere.

This
fresh layer is deposited on a water-ice layer that exists year round.

Strong
winds blow down
from above the cap’s center and swirl due to the spin of
the red planet —
contributing to
Planum Boreum‘s spiral structure.

The featured image is a perspective mosaic
generated in 2017 from numerous images taken by ESA’s Mars Express and elevations extracted from the
laser altimeter aboard NASA’s
Mars Global Surveyor mission.