Mysterious Martian Grooves Carved by Dry Ice Chunks?

It appears Mars may one day become a premier extreme snowboarding destination.

NASA research released this week indicates that mysterious, long narrow grooves carved into the slopes of giant Martian sand dunes may in fact be generated by gliding chunks of dry ice. Scientists have observed the grooves via images from NASA’s Mars Reconnaissance Orbiter and other instruments for about a decade. (Also see “Mars Snow Falls Like Dry Ice Fog.”)

martian gully picture
An image from the Mars Reconnaissance Orbiter shows grooves now believed to be created by dry ice blocks surfing down the slopes. Image courtesy NASA/JPL-Caltech/Univ. of Arizona/EPA

“I have always dreamed of going to Mars,” study leader Serina Diniega, a planetary scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a NASA statement.

“Now I dream of snowboarding down a Martian sand dune on a block of dry ice.”

Bizarre Grooves Explained

Called linear gullies, these bizarre grooves stretch down hillsides for up to 1.2 miles (2 kilometers) and are only a few meters wide, with raised banks or levees along the sides. (See another picture of Martian gullies.)

Diniega and her team believe these gullies are formed as the Martian surface warms during springtime, when a layer of carbon dioxide frost—commonly referred to as dry ice—vaporizes. This causes blocks of dry ice to break off and glide down the slopes on a cushion of carbon dioxide vapors, cutting the visible linear gullies into the sand, according to the study, published online June 11 by the journal Icarus.

They came to this conclusion after analyzing before-and-after images from different seasons showing the formation of new gullies and even spotting bright, white objects within the grooves.

To support the theory, the team conducted experiments here on Earth by sliding dry ice down sand hills in Utah and California, which replicated perfectly the features seen on Mars—despite differences in air pressure and temperature.

As final evidence of these surfing ice blocks, researchers noticed multiple pit formations at the bottom of the hills, which they think are where the blocks came to rest before turning into gas.

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Meet the Author
Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.