The sun dominates our lives by defining our day, but how much do you know and understand about it? This unit will help you to explore the workings of the brightest star in our universe looking at its structure and the main processes taking place within it. You will also examine the phenomena of sun spots. This study unit is just one of many that can be found on LearningSpace, part of OpenLearn, a collection of open educational resources from The Open University. Published in ePub 2.0.1 format, some feature such as audio, video and linked PDF are not supported by all ePub readers.