NASA's Mars Perseverance rover has stumbled across an unusual sight: a stack of rocks on the Martian surface. How did they end up this way? Did Perseverance knock them over? So many questions. What is it? Perseverance, or Percy for short, captured this bizarre image of rocks stacked on Mars on May 13(or Sol 1859, the rover's 1,859th day on the Red Planet). The image was captured with the rover's Mastcam-Z camera — a pair of two cameras located high up on the rover's mast, looking almost like a pair of eyes that the craft sees through. You may have...