THE EXTRAORDINARY GEOLOGY OF THE KUIPER BELT: PLUTO, CHARON, AND ARROKOTH (Invited Presentation)

On July 14, 2015 the New Horizons spacecraft flew through the Pluto system, completing humanity’s reconnaissance of the classical planets. Pluto turned out to be a world of remarkable geologic diversity, and its surfaces display a range of ages, suggesting geologic activity of various forms has persisted for much of Pluto’s history. Pluto has both familiar and unique geologic features, including tectonics, impact cratering, sublimation terrains, a giant convecting nitrogen and methane ice sheet, and putative cryovolcanic features. Pluto’s large moon Charon appears to have had an early large cyrovolcanic resurfacing episode along with large-scale tectonism.

On January 1, 2019 New Horizons encountered a smaller Kuiper Belt Object called Arrokoth at 43 AU, making it the farthest planetary body ever explored by a spacecraft. Arrokoth is a bi-lobed contact-binary approximately 35 km across. It is remarkably lightly cratered, with possible tectonic structures including some enigmatic arcuate structures on the large lobe. Arrokoth is an ancient body that is yielding insights into the building blocks of the planets.

I will highlight some of the major findings and new results from the New Horizons exploration of these Kuiper Belt worlds.