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Hello 26,000 light years from the center of our galaxy in one of the outer reaches of the

Milky Way is an unremarkable little star. Astronomers describe it as a G-type main sequence star and in most respects there's nothing

interesting or unusual about it but ever since humanity first walked on the planet

it's been an objective fascination for one very good reason it's the sun our sun. The sun's

been burning for four and a half billion years and it's the source of all our

energy. At its core nuclear reactions of almost unimaginable power generate heat and light,

which takes 100,000 years to penetrate the surface,

but they had only another eight minutes to reach us on Earth.

The greatest minds have been studying our nearest staff for millennia, but only in recent decades

have we begun to have some inkling and the astonishing processes at work inside it.

With me to discuss the signs of the sun, I Carolyn Crawford, Gresham Professor

of Astronomy and Fellow of Emmanuel College Cambridge, Yvonne Ellsworth, Pointing Professor of Physics

at the University of Birmingham, and Louise Hara Professor of S at the University of Birmingham and Louise Harrah Professor of

Solar Physics at the UCL Mulatch Science Laboratory.

Carolyn Crawford, let's start with the basics. What would you give us a quick idea of

the size nature, sun?

Well as you say it's a star, our nearest star which we view from the relatively close vantage point

of 150 million kilometers away, so this is astronomically speaking of course and it's

...