December 2014 | The Sun in Action

Look up on any clear night and you can see thousands of stars, all of different colours and sizes. Our Sun is a star, a perfectly ordinary star; it is so brilliant because we are in orbit around it at a safe distance, which makes it so easy to study.

We are now at Sunspot Maxima and there have been some surprisingly gigantic spots on view, along with mega solar flares. This month's program looks at the Sun and what makes it radiate.

Magnetic reconnection drives all aspects of solar activity. They determine the shape and structure of the corona, and play a major role in perhaps the most dramatic of all solar events: coronal mass ejections (CMEs), in which vast shells of plasma, with intertwined magnetic fields, are catapulted out through the corona into space. Each CME contains around a thousand million tons of plasma, and they hurtle outward at speeds ranging from 200 to over 2400 kilometres per second.

A number of professional amateur astronomers have helped me in putting this month's program together. I would like to acknowledge the valuable assistance of Pamela Shivak, Pete Williamson FRAS., Les Cowley, and Pete Lawrence (Sky at Night Team). Also everyone one who has allowed me to use their images of the Sun .. thank you.