Sometimes an unusual landscape here on our little planet prompts Earthlings to exclaim, "It looks like Mars!" And it's true, some of Earth's redder and dustier haunts do resemble our neighbor planet. But Mars also has certain features that could never appear on Earth, and one of those is something called "linear gullies," and they're pretty beautiful.
What are these things? Well, that's what NASA scientists were wondering, too. On Earth, when water flows down a slope it will leave a triangular deposit known as a "debris apron." But these furrows on Mars could run for more than a mile, and then end suddenly in a pit. What caused these gashes, and where did whatever it was go?
The culprit, scientists believe, was frozen carbon dioxide and it turned into a gas. According to a new report, the lines were carved out by dry ice, frozen during the Martian winter. As the ice sublimated, the gas acted as a sort of cushion for the solid piece as it slid down the Martian hillside. "This process wouldn't happen on Earth," said NASA scientist Serina Diniega in a press release. "You don't get blocks of dry ice on Earth unless you go buy them."
"I have always dreamed of going to Mars," Diniega mused. "Now I dream of snowboarding down a Martian sand dune on a block of dry ice."
A video from NASA shows the scientists recreating the process on some terrestrial dunes: