This image was made by the Long-Range Intelligence Imaging Unit (LORRI) mounted on the New Horizons NASA spacecraft, shortly before the closest approach to Pluto on July 14, 2015. The resolution is at least 270 yards (250 meters). The size of the area shown is approximately 130 miles (210 kilometers). The sun shines from the left side.
Like a log-infected larva, a new photograph of NASA’s New Horizons dwarf planet Pluto showed a pockmarked landscape that is as puzzling as it is beautiful.
Made just before NASA’s mission came close on July 14, this new image of an ice field called “Satellite Planum” on Pluto shows hundreds of holes “swarming” across the surface, several hundred meters wide and several tens of meters deep. According to the first assumptions of planetologists, the formation of such holes is due to the sublimation of ice, like the nitrogen ice of which they are composed. However, the alignment and location of the pits remains a mystery.
Sublimation occurs when the ice becomes vapor, without passing through the liquid form. Like “dry ice” on Earth (carbon dioxide ice), nitrogen ice enters the gas without passing through the liquid phase. Since atmospheric pressure on Pluto is low, sublimation is the dominant process and abundant surface ices when heated release gases into a rarefied atmosphere, forming a surprisingly complex interaction between the surface and the atmosphere. Indeed, the amazing absence of asteroid craters on Sputnik Planum shows that the surface is constantly being refreshed with new ice, probably laid out in layers when deposited from the atmosphere, and these holes are tangible evidence of this oddly active ice layer.
“Pluto is odd, in a good way,” said New Weakons project coordinator Hal Weaver from the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. “The pits and the way they are aligned give an idea of the ice flow and the exchange of volatile components between the surface and the atmosphere, and the scientific team works hard to understand which physical processes play a role here.”
It is hard not to imagine what this landscape would look like if we could stand on the surface of the Planum Satellite. We already know that this area is largely flat, but the inclusion of these holes would make it look like an ocean of dramatic drainage wells in the ice, stretching to the horizon.
One of the biggest surprises delivered by the New Horizons flight is the interesting dynamism of Pluto. The fact that in a tiny world located in the Kuiper Belt, almost 50 times farther from the Sun than the Earth, there is volcanic activity that manifests itself on the surface of Pluto, is surprising. But it is likely that even in the inner regions of the solar system, the ancient worlds remain active, and even the smallest trickle of heat from the sun and planetary formation may be sufficient for a dramatic impact on the geology of these worlds. A little more than 4 short months ago, we had some clues about how dynamic and diverse the surface of Pluto will be, but the New Horizons have fundamentally changed our understanding of Pluto and what the active little ice worlds can be.