APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
The Spiral North Pole of Mars
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.
| Date | July 6, 2025 |
|---|---|
| Credit | Image Credit: ESA / DLR / FU Berlin ; NASA MGS MOLA Science Team |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |
