The moving hills of Pluto are icebergs moving on ice. It may sound whimsical, yet this is the conclusion scientists reaches after analyzing the latest batch of images received from New Horizons.
Organized in clusters, these moving hills may stretch for miles across Pluto’s surface. At the same time, the wide iceberg clusters are moving. New Horizons captured these images from a distance of 9,950 miles from the dwarf planet’s surface on July 14th, 2015. It was the same day when New Horizons made history only 12 minutes later. At the time, the orbital craft reached 7,800 miles from Pluto’s surface, the closest flyby ever performed.
Captured with the Multispectral Visible Imaging Camera aboard New Horizons, the large image sports a resolution of 1,050 feet per pixels and covers 300 per 210 miles. That is a large enough surface stretch for the moving hills of Pluto to be imaged correctly. Except that the hills aren’t really hills.
According to NASA scientists working behind the scenes of the New Horizons mission, the clusters of moving hills are in fact icebergs. More interestingly, these icebergs move around on massive ice. While it may be difficult to grasp, the scientific team declared that the icebergs are quite similar to what we see on Earth.
Water ice is less dense than another type of ice present on Pluto’s surface. That is nitrogen ice. According to NASA:
“Because water ice is less dense than nitrogen-dominated ice, scientists believe these water-ice hills are floating in a sea of frozen nitrogen”.
Much like the icebergs floating in the Arctic Ocean, the water ice icebergs on Pluto’s surface are now carried towards the Sputnik Planum. If you remember, the Sputnik Planum is the heart-shaped region on the dwarf planet, a fascinating planum ridden with water ice hills. At the heart of the Sputnik Planum there are massive block of nitrogen-ice. It is here that scientists observed the moving hills of Pluto are icebergs moving on ice.
The process may be triggered by the thermal-convection processes in the region. When water ice reaches the nitrogen ice cell, the icebergs are pushed to the margin. That explains the moving hills clusters observed in the latest New Horizons image.
The largest of these clusters measures 37 miles in length and 22 miles in width. Due to its prominence, NASA officials informally tagged it as the Challenger Colles. The name honors the seven astronauts who passed away on January 28th, 1986 with the explosion of the Challenger space shuttle.
Photo Credits: NASA.gov