Pluto is no longer the solar system's beloved ninth largest planet, but it's still getting plenty of special attention from scientists. NASA recently shared an image (above), captured by the New Horizons spacecraft, that revealed what the space agency calls "floating hills" on the dwarf planet's surface.
The hills are located in an icy region named Sputnik Planum and their movement has been compared to icebergs in the Arctic Ocean. "Because water ice is less dense than nitrogen-dominated ice, scientists believe these water ice hills are floating in a sea of frozen nitrogen," according to a statement from NASA.
According to NASA, the hills formed when sections of Pluto's rugged uplands (located on the right side of the photo) broke off. As the hills floated around the nitrogen glaciers, they combined to form larger chains. The largest collection, measuring 37 x 22 miles, is the Challenger Colles. The chain was discovered in July 2015 by the New Horizons spacecraft and named in honor of the crew that died aboard the space shuttle Challenger in 1986.