"New Horizons"'s cameras have spied swarms of mysterious "pits" across Pluto's informally named Sputnik Planum. Scientists believe the pits may form through a combination of sublimation and ice fracturing. In the image at left, some of the pits appear to have dark material inside. The left and right images are about 120 km (75 miles) and 93 km (58 miles) wide, respectively.