关于这张图
This animation shows a side-by-side comparison of CO2 ice at the north (left) and south (right) Martian poles over the course of a typical year (two Earth years). This simulation isn't based on photos; instead, the data used to create it came from two infrared instruments capable of studying the poles even when they're in complete darkness. As Mars enters fall and winter, reduced sunlight allows CO2 ice to grow, covering each pole. While ice at the north pole is fairly symmetrical, it's somewhat asymmetrical during its retreat from the south pole for reasons scientists still don't understand.…
