Planets: Royal Observatory Greenwich Illuminates

From a planet with a hexagonal storm to the home of the Solar System's largest volcano, our neighbouring bodies are unique and fascinating places. Where else would you find somewhere with days longer than its years? Humanity's understanding of planets has changed drastically since ancient times when early astronomers mistook the lights they saw in the sky for wandering stars. We've come a long way since then, but there's still so much we don't know. Could there be life on Mars? How many pla...