The flyby of Pluto by NASA’s New Horizons spacecraft in July 2015 has revolutionised our understanding of its topography. Earth-based measurements of Pluto’s atmosphere using the technique of stellar occultations extend back over the past 30 years, including measurements taken nearly simultaneously with the New Horizons flyby. In particular, observations by our group rule out a thermal collapse of Pluto’s atmosphere caused by cooling as it moves away from perihelion. We find a nearly haze-free atmosphere with a monotonically increasing atmospheric pressure that has increased by about a factor of 3 since 1988. I will discuss the history of measurements of Pluto’s atmosphere and the early returns from spectroscopic, imaging, and particle detector measurements by New Horizons. Continuing analysis of the New Horizons data is expected to dramatically advance our knowledge of the surface and atmospheric physics of small bodies in the Kuiper belt, 30-50 AU from the Sun, and to shed new light on the processes that form the outer solar system. 

Dr Andrew Cole is a Senior Lecturer in physics at the University of Tasmania. He uses optical and near-infrared telescopes to study the formation and evolution of dwarf galaxies in the nearby Universe, and to search for exoplanets using the technique of gravitational microlensing. He received his PhD in astronomy from the University of Wisconsin-Madison, and is a regular user of 8-10m class telescopes and the Hubble Space Telescope. Since 2013 he has been Director of the UTAS Greenhill Observatory.