1404/04/15 - 10 محرم 1447 - 2025/07/06
العربیة فارسی

Astronomical Research Center (A.R.C.)

Astronomy Picture of the Day

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.
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