A dust layer sandwiched between layers of ice near Mars's north pole suggests the planet's climate has shifted dramatically in the past 100,000 years or so, reveal images recently obtained by NASA's Mars Reconnaissance Orbiter (MRO). Previous research has suggested that the tilt of Mars's axis of rotation fluctuates from 10° to 40° with time, leading to major climate shifts (see Wrecking ball could break the ice on Mars). Now MRO, which started returning close-up images of the Red Planet in late September, has provided new evidence that Mars's climate has undergone major shifts relatively recently.
