Penises on Mars? Grow Up, Internet
NASA's Spirit Mars rover created these tracks shortly after touching down in 2004 to execute a turn, not amuse its handlers.
Credit: NASA/JPL/Cornell

Has juvenile humor landed on Mars? The Internet is buzzing today (April 24) over a phallic design etched into the Red Planet's surface nine years ago by NASA's Spirit rover, with some folks suggesting the robot's drivers drew it on purpose out of boredom, mischievousness or some combination of the two.

But the truth is much more prosaic. The phallic shape naturally resulted when the six-wheeled Spirit, which was declared dead in 2010, made a turn, as NBC News' Alan Boyle points out. NASA's currently active Mars rovers — Spirit's twin Opportunity and the much larger Curiosity — have also made similar tracks on the Red Planet.

The photo of Spirit's tracks, which was taken by the rover itself, exploded into a bona fide meme after a forum on the popular social-news site Reddit discovered it on Tuesday (April 23). Penis graffiti on Mars? In retrospect, it's surprising it took so long.

No planet is more steeped in myth and misconception than Mars. This quiz will reveal how much you really know about some of the goofiest claims about the red planet.
The original 'Face on Mars' image taken by NASA's Viking 1 orbiter, in grey scale, on July, 25 1976. Image shows a remnant massif located in the Cydonia region.
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Mars Myths & Misconceptions: Quiz
No planet is more steeped in myth and misconception than Mars. This quiz will reveal how much you really know about some of the goofiest claims about the red planet.
The original 'Face on Mars' image taken by NASA's Viking 1 orbiter, in grey scale, on July, 25 1976. Image shows a remnant massif located in the Cydonia region.
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Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @SpacedotcomFacebook or Google+. Originally published on SPACE.com.