Blocks of carbon dioxide ice appear to carve mysterious gullies on Mars as they melt along dunes and blast away sand — a process that looks eerily like the burrowing of fictional sandworms in the movie "Dune."
Planetary scientists have long puzzled over strange, sinuous trenches etched into desert dunes on the Red Planet. The channels look freshly dug, complete with raised rims and winding paths, yet Mars today is too cold, too dry and too lifeless for running water — or giant worms — to be the cause.
