Mars, Like Earth, Has Cyclical Ice Ages, Study Says Brian Handwerk for National Geographic News September 14, 2007 Mars has gone through 40 ice ages during the past five million years that regularly send the planet's permanent ice sheets cascading toward the equator, then melting backward, a new theory suggests. The climate changes are likely driven by cyclical fluctuations in the planet's orbit that alter the amount of sunlight that falls on the planet's surface, says astronomer Norbert Schörghofer of the University of Hawaii at Manoa. Understanding the sun's exact role in the Martian ice ages could help solve longstanding...