Pluto has icebergs, NASA revealed today. By analyzing data and images returned by the New Horizons spacecraft, scientists determined that these icebergs are actually very large. They measure several miles across, and traverse the icy plains region being called Sputnik Planum, which makes up half of the large heart shape on the dwarf planet's now familiar face.
New Horizons scientists believe that these iceberg clusters are smaller, less mature versions of nearby mountains. Over time, these hills break free from the mountains and follow the flow of the nitrogen-rich glaciers that make up Sputnik Planum. These iceberg chains are slowly dragged out into the plains in the path of the drifting glaciers. Convection forces eventually push them back out toward the shoreline, where they form clusters that stretch as far as 12 miles (20 kilometers) across.
The icebergs are likely young runaway mountains
One particularly massive cluster measures 37 by 22 miles (60 by 35 kilometers) big, and features dozens of icebergs. NASA believes that this is a result of the icebergs becoming "beached" in the shallow ice at the edge of Sputnik Planum.