  The Pluto system was recently explored by NASA's New Horizons spacecraft,
making closest approach on 14 July 2015. Pluto's surface displays diverse
landforms, terrain ages, albedos, colors, and composition gradients. Evidence
is found for a water-ice crust, geologically young surface units, surface ice
convection, wind streaks, volatile transport, and glacial flow. Pluto's
atmosphere is highly extended, with trace hydrocarbons, a global haze layer,
and a surface pressure near 10 microbars. Pluto's diverse surface geology and
long-term activity raise fundamental questions about how small planets remain
active many billions of years after formation. Pluto's large moon Charon
displays tectonics and evidence for a heterogeneous crustal composition, its
north pole displays puzzling dark terrain. Small satellites Hydra and Nix have
higher albedos than expected.
