200 The Chemistry of Pluto Dwarf Planet of Ice and Mystery (S1E200)

In this illuminating episode, we delve into the fascinating world of Plutonian chemistry, where this distant dwarf planet reveals unexpected complexity despite its frigid environment. Through engaging interviews with planetary scientists and astrochemists, we explore how Pluto's surface—dominated by nitrogen, methane, and carbon monoxide ices—creates a dynamic landscape that changes with its 248-year orbit around the sun. Our journey takes us from the iconic heart-shaped region Tombaugh Regio, with its smooth nitrogen ice plains, to the methane glaciers flowing across the surface, where we'll examine how these volatile compounds cycle between solid and gas phases in Pluto's tenuous atmosphere. We'll investigate the crucial role of the New Horizons flyby in revolutionizing our understanding of this distant world, explaining how instruments detected not only these ices but also complex organic compounds and evidence of past cryovolcanism.

Through detailed demonstrations, we'll showcase how Pluto's unique chemistry creates an environment where familiar substances behave in alien ways, explaining why nitrogen ice flows like a glacier despite temperatures of -390°F (-235°C). We'll investigate the mysterious dark reddish material found in some regions, examining how complex organic molecules called tholins form when methane and nitrogen are exposed to ultraviolet radiation. The episode highlights cutting-edge research from New Horizons data analysis, from the detection of water ice mountains to the mapping of diverse chemical terrains across Pluto's surface. Finally, we'll explore how Pluto serves as a natural laboratory for studying the chemistry of the outer solar system, from the processes that have shaped its surface over billions of years to what its composition reveals about the early solar nebula, all while explaining the remarkable chemical processes that make this dwarf planet both distant and intimately connected to the story of our solar system's formation.