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The surface of Pluto is marked by plains, troughs and peaks that appear to have been carved out by geological processes that have been active for a very long period and continue to the present, a new study says. The study represents the first published results from the flyby of the Pluto-Charon system earlier this year. NASA's New Horizons mission continues to download information gathered from Pluto and its moon Charon during its historic flyby on 14 July, 2015. As this data arrives on Earth, scientists process and study it. Here, Alan Stern and colleagues overview some of the first results from this effort. Data on the variability of craters on Pluto suggests the dwarf planet has been frequently resurfaced by processes like erosion or crustal recycling, though the energy source to power these resurfacing activities is unclear, Stern and colleagues say. But the results do point to active geomorphic processes within the last few hundred million years, probably continuing to the present. Data from New Horizons also reveal that Pluto's surface is home to large regions of differing brightness and areas carved out by structures similar to terrestrial glaciers. Charon's surface is similarly complex, with rolling plains, moat-like depressions, and evidence for tectonics. Atmospheric pressure is lower than expected in Pluto's atmosphere, New Horizons' instruments show, though it is unclear whether this reflects a recent decrease in the mass of the atmosphere. Charon has no detectable atmosphere, the data reveal. Pluto's small moons, Nix and Hydra, both have reflective surfaces, suggesting relatively clean water ice. Taken together, these initial results from the flyby of Pluto pave the way for scientists' better understanding of processes of planetary evolution.
Note: This paper will be available for free when the embargo lifts at http://www.
Article #8: "The Pluto system: Initial results from its exploration by New Horizons," by S.A. Stern; C.B. Olkin; J.R. Spencer; L.A. Young; J. Andrews; E. Birath; M.W. Buie; C.A. Conrad; J.C. Cook; Z.J.B. Dischner; T. Finley; A. Harch; C.J.A. Howett; J.A. Kammer; D.E. Kaufmann; N. Martin; A.H. Parker; J.W. Parker; J. Peterson; S.B. Porter; J. Redfern; H.J. Reitsema; S.J. Robbins; D. Rose; E. Schindhelm; K.N. Singer; A.J. Steffl; C.C.C. Tsang; M. Vincent; A.M. Zangari at Southwest Research Institute in Boulder, CO; F. Bagenal; M. Horanyi; M. Piquette; J.R. Szalay at University of Colorado in Boulder, CO. For complete list of authors, see the manuscript.