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ISSUE 7 - November 2009

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Explained in 60 Seconds (page 04)
Lee Pullen

The End of the Sun

Our Sun is a star, a ball of gas just like the thousands of other twinkling pin-pricks of light in the night sky. Stars have finite lifespans, so eventually they “die”. Our Sun has enough fuel to be a regular star for ten billion years. It’s about halfway through that at the moment, in what we call the main sequence. This is when nuclear fusion converts hydrogen into helium. Each second the Sun turns four million tonnes of material into energy. No wonder it’s so hot and bright!

In five billion years the hydrogen will be used up and the Sun will become a red giant — bad news for the Earth, which is destined to be boiled and engulfed. Eventually the Sun’s outer layers will be cast off, becoming a beautiful nebula. The core will be left as a white dwarf, slowly cooling over an eternity. A peaceful end for our nearest star.


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