关于这张图
It's spring in the Northern Hemisphere of Mars, and the polar region is still blanketed by seasonal carbon dioxide frost (dry ice). This image shows an area near the sand sea (called an "erg") that is surrounding the water ice-rich layered deposits. The many bumps are sand dunes less than 100 meters across that are mostly covered by seasonal frost, appearing in a manner that looks artificial but is a natural consequence of the wind patterns in this region. The smaller, darker spots are places where the seasonal frost has sublimed away, exposing the dark surface below. The combination of these…
