Meetings
Map of UOP
7:30 PM Thursday October 11th
Stockton Astronomical Society
Presents
Dr. Orkan Umurhan
Peering into distant lands: New Horizons and the
geology of Pluto and Charon
NASA’s New Horizons spacecraft has revealed that Pluto and Charon exhibit strikingly different surface appearances, despite their similar densities and presumed bulk compositions. After an introductory background and a discussion about the New Horizons spacecraft and its upcoming close-encounter mission with Ultima Thule (January 1, 2019), this talk will present an overview of our main findings centering on the fascinating geology of Pluto. Much of Pluto’s surface can be attributed to surface-atmosphere interactions and the mobilization of volatile ices like N2 and CH4 by insolation. Many valley systems appear to be the consequence of glaciation involving N2 ice. Other observed signs of geological activity requires or required internal heating – for example, the solid-state convection and advection of volatile ices in
Sputnik Planitia can be powered by present-day radiogenic heat loss. On the other hand, the prominent mountains at the western margin of Sputnik Planitia, and the strange, multi-km-high mound features to the south, probably composed of H2O, are young geologically as inferred by light cratering and superposition relationships. Their origin, and what drove their formation so late in Solar System history, is under investigation. The dynamic remolding of landscapes by volatile transport seen on Pluto is not unambiguously evident on Charon. Charon does, however, display a large resurfaced plain and globally engirdling extensional tectonic network attesting to its early endogenic vigor.