Figure 11-27: R I V U X G
Changing Seasons Reveal Water-Ice at the Martian North Pole (a) During the Martian winter, the temperature drops so low that carbon dioxide freezes out of the Martian atmosphere to make a large polar ice cap of carbon dioxide. During summer, the carbon dioxide returns to the atmosphere, revealing a residual ice cap made of water. (b) The dark canyon, Chasma Boreale, is more than 300 km long—similar in length and depth to the Grand Canyon, Arizona. Spectra reveal the residual ice is made of water and not CO2.
Changing Seasons Reveal Water-Ice at the Martian North Pole (a) During the Martian winter, the temperature drops so low that carbon dioxide freezes out of the Martian atmosphere to make a large polar ice cap of carbon dioxide. During summer, the carbon dioxide returns to the atmosphere, revealing a residual ice cap made of water. (b) The dark canyon, Chasma Boreale, is more than 300 km long—similar in length and depth to the Grand Canyon, Arizona. Spectra reveal the residual ice is made of water and not CO2.
(a: S. Lee/J. Bell/M. Wolff/Space Science Institute/NASA; b: (left) NASA; (right) Mars Reconnaissance Orbiter, NASA/Caltech/JPL/E. DeJong/J. Craig/M. Stetson)