Probing the Mysteries of Our Nearest Star...

Abstract

Lying at a safe distance of 150 million kilometres from the Earth, and reassuringly rising and setting every day, one tends to think of our friendly local star as a very predictable and stable body with little variation in its behaviour. However, the Sun follows a roughly 11-year cycle of activity (22 years if one considers its magnetic cycle) and at every solar maximum (the next is predicted to be around 2011) we see its 1.4-million-kilometre diameter disc sporting many large sunspots and producing enormous outbursts. These can bring down national grid power systems on Earth (causing blackouts), interfere with radio communications, damage orbiting satellites and threaten the safety of astronauts working in space.