'Dog door' on Mars found by Curiosity rover is a rocky 'doorway into ancient past,' NASA says - Space.com

Yes, the Mars "door" is just a rock. But the Curiosity rover's find is a boon for science, too.

Over the past week, the internet has been wild over images of what appears as a doorway cut into a cliff on Mars.  But scientists behind NASA's Curiosity rover, which snapped the pictures earlier th… [+2525 chars]

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