Although the New Horizons spacecraft has moved on from Pluto, it’s still sending its data back to Earth. The latest batch of pictures, snapped on July 14, just 15 minutes after its closest approach to the dwarf planet, arrived on Earth on September 13, and absolutely stunned NASA scientists with their beauty.
Taken as New Horizons flew away from Pluto, at a distance of 18,000 kilometres (11,000 miles) away, the images show details of the Plutonian landscape, dramatically backlit by the sun: icy mountain ranges, nitrogen in frozen rivers and atmospheric hazes that hang over the horizon.
“This image really makes you feel you are there, at Pluto, surveying the landscape for yourself,” New Horizons principal investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado, said in a NASA release September 17. “But this image is also a scientific bonanza, revealing new details about Pluto’s atmosphere, mountains, glaciers and plains.”
Beautiful Pluto: mountains, glaciers, plains and fog. This scene is 1,250 kilometres (780 miles) wide. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
The image was taken by New Horizons’ high-resolution, wide-angle Ralph Multispectral Visible Imaging Camera and shows the atmosphere in detail. At least a dozen thin haze layers can be identified in Pluto’s nitrogen atmosphere, up to an altitude of around 100 kilometres (60 miles).
There’s also at least one fog-like haze bank that can be identified, low to the ground and backlit by the sun and shadowed by mountains. This hints that Pluto’s weather could be as changeable as weather on Earth.
The fog could be part of what the research team has identified as a surprising water cycle, like we see on Earth: evaporation, condensation and precipitation, but with frozen nitrogen rather than frozen water.
The Sputnik Planum plains to the right, with mountains up to 3,500 metres (11,000 feet) high to the left, including Norgay Montes and Hillary Montes on the skyline. This scene is 380 kilometres (230 miles) wide. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
There appear to be patches of nitrogen ice east of the informally named Sputnik Planum plain, which may have evaporated from the plain and reformed in their current location. Glaciers, too, have been identified flowing from this region back to the Sputnik Planum, similar to glaciers in Greenland and Antarctica.
“We did not expect to find hints of a nitrogen-based glacial cycle on Pluto operating in the frigid conditions of the outer solar system,” said Alan Howard, a member of the mission’s Geology, Geophysics and Imaging team from the University of Virginia, Charlottesville.
“Driven by dim sunlight, this would be directly comparable to the hydrological cycle that feeds ice caps on Earth, where water is evaporated from the oceans, falls as snow, and returns to the seas through glacial flow.”
Stern added, “Pluto is surprisingly Earth-like in this regard, and no one predicted it.”
Pluto, you so crazy (pictures)