Double Crater

Bull's Eye on Mars

Image courtesy NASA/JPL/University of Arizona

Did Martian geology carve this concentric impact crater, or did a second space rock make a bull's eye? Taken July 9 by the HiRISE camera aboard the Mars Reconnaissance Orbiter, the recently released picture shows an impact crater with a slightly off-center pit in its middle.

Mars experts aren't sure whether the pit formed due to erosion of icy and non-icy layers inside the crater or due to a second—and oddly lucky—impact even