Gully patterns document Martian climate cycles

January 30, 2015
Martian gullies, old and new

Sharp-featured, relatively recent gullies (blue arrows) and degraded older gullies (gold) in the same location on the surface of Mars suggest multiple episodes of liquid water flow, consistent with cyclical climate change on the Red Planet. 

Credit: NASA HiRISE

Gullies carved into impact craters on Mars provide a window into climate change on the Red Planet. A new analysis suggests Mars has undergone several ice ages in the last several million years. The driver of these climate swings is likely the Red Planet's wobbly axis tilt. Read the study, in press in the journal Icarus, by lead author Jay Dickson.