NASA sees 'spiders' crawling across Mars landscape

Don't worry. They don't bite.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
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Mars' South Pole carbon dioxide ice cap spits out "spiders" in the spring.

NASA/JPL/University of Arizona

The Spiders from Mars might have been David Bowie's backing band here on Earth, but that term has a different meaning when we're talking about the actual Red Planet. 

NASA shared a creepy-crawly landscape view from Mars this week as part of its Image of the Day series. The scenic look at the planet's South Pole comes from the space agency's Mars Reconnaissance Orbiter (MRO) and it shows "spiders" emerging from the ground. 

The spiders are known in science circles as "araneiform terrain." NASA says these are "spider-like radiating mounds that form when carbon dioxide ice below the surface heats up and releases." The MRO captured the image on May 13 as spring was dawning on Mars. 

NASA goes deeper into the process behind these leggy formations: The spiders return seasonally as carbon dioxide ice morphs from a solid into a gas. That gas builds up under the surface before breaking through in jets that deposit dark dust around the vent. The wind may also play a role in arranging the streaky-looking legs of dust. 

While Mars and Earth have a lot of crossover when it comes to landscape activity (I'm looking at you, dunes and frost heave), the process that creates the spiders is not seen here on our home planet.

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