Photo: Mars, Like Earth, Has Cyclical Ice Ages, Study Says



Mars has experienced 40 ice age cycles in the past five million years, a new study suggests.

According to the theory, Mars's permanent ice layer (left) recedes when the planet tilts away from the sun (second from left). When Mars tilts toward the sun, the ice layer expands beyond its original boundary (second from right).

The impending arrival on Mars of the Phoenix lander, which will dig into Mars's underground (right), will help determine the theory's accuracy.

Images courtesy Norbert Schörghofer, University of Hawaii


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