Blocks of carbon dioxide ice seem to carve mysterious gullies on Mars as they soften alongside dunes and blast away sand — a course of that appears eerily just like the burrowing of fictional sandworms within the film “Dune.”
Planetary scientists have lengthy puzzled over unusual, sinuous trenches etched into desert dunes on the Purple Planet. The channels look freshly dug, full with raised rims and winding paths, but Mars at the moment is just too chilly, too dry and too lifeless for working water — or large worms — to be the trigger.
Instead, a new study suggests that the gullies are sculpted by slabs of dry ice that form during the Martian winter. As spring approaches and temperatures warm, the sand heats up and blocks of ice break off, sliding and sublimating their way through the Martian sand, according to a statement from Utrecht College.
Inside a Mars simulation chamber, researchers positioned carbon dioxide (CO2) ice blocks atop small sand dunes underneath low stress and frigid temperatures to imitate the Purple Planet’s surroundings. Because the ice warmed, it started to sublimate, turning immediately from strong to fuel. Fuel trapped beneath the block constructed stress till it vented explosively, lifting and propelling the ice downslope. Because it glided, the block plowed a slender trench and pushed sand apart into small levees — forming miniature variations of the gullies seen throughout Mars from orbit.
“It felt like I used to be watching the sandworms in the film ‘Dune,'”Lonneke Roelofs, lead author of the study and an Earth Scientist from Utrecht University, said in the statement. “In our simulation, I saw how this high gas pressure blasts away the sand around the block in all directions.”
The study helps rule out other possible sources behind these gullies, such as liquid water, which would have implications for potential Martian habitability. Instead, the dry-ice process offers a purely physical, water-free explanation — proof that Mars can still reshape itself today, even without rivers or rainfall. Studying the formation of structures on other planets also offers new insight for understanding Earth’s landscape by looking at underlying processes through a different lens, the researchers said.
“We tried out various things by simulating a dune slope at different angles of steepness. We let a block of CO2 ice fall from the top of the slope and observed what happened”, Simone Visschers, co-author of the study and master student at Utrecht University, said in the statement. “After finding the right slope, we finally saw results. The CO2 ice block began to dig into the slope and move downwards just like a burrowing mole or the sandworms from ‘Dune.’ It looked very strange!”
While no sandworms roam the Martian deserts, its dunes may indeed come alive each spring — when slabs of dry ice briefly tunnel through the sand and etch new gullies across the planet’s surface.
Their findings were published on Oct. 8 within the journal Geophysical Analysis Letters.
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