Did life really exist on Mars after all? Unfortunately, there is no conclusive evidence for this yet. Nevertheless, it would seem that some form of life was the driving force behind the mysterious Martian dune gullies. Earth scientist Dr. Lonneke Roelofs from Utrecht University has investigated how these gullies were formed. In a test setup, she observed that blocks of CO2 ice "dug" these gullies in a unique way.