Author: Nico Orce, Full Professor of Physics, University of the Western Cape

When the International Astronomical Union announced in 2006 that Pluto was being demoted from its status as the Sun’s ninth planet, many astronomers and non-experts alike were shocked. Pluto remains an important object for study, though. Today it is considered one of many dwarf planets beyond Neptune, in a doughnut-shaped region of mostly icy debris orbiting the Sun called the Kuiper Belt. These outskirts of the solar system remain largely unexplored. They were first reached by US space agency NASA’s New Horizons spacecraft; it flew close to Pluto in 2015, revealing spectacular images of the dwarf planet’s surface and atmosphere.…