• Question: how long is it until the sun blows up and what is going to happen to the sun

    Asked by stansfjr01 to Amelia, Jim, Liz, Prateek, Richard on 16 Jun 2011.
    • Photo: Jim Caryl

      Jim Caryl answered on 14 Jun 2011:

      Hi, well, it’s not really my area of specialism, but it is an area of physics I like to read about.

      According to this page (http://www-istp.gsfc.nasa.gov/istp/outreach/workshop/thompson/facts.html) the sun will have enough fuel for 5 billion years (roughly the same amount of time it will take Tim Henman to win Wimbledon), after which time it will swell into a red giant star, engulfing the inner planets, including Earth.

      Once the sun has thrown off most of its material to form a nebula, the core of what is left will form a much smaller white dwarf star, which can slowly radiate the last of its heat for a few billion years before winking out into blackness.

      I’d like to believe that somewhere across the galaxy, or in another galaxy, some other form of intelligent life may look over at our corner of the universe, and see a beautiful nebula cloud, all that will be left of our solar system. They might even wonder whether there was once intelligent life over here.

    • Photo: Amelia Markey

      Amelia Markey answered on 14 Jun 2011:

      Well I think Jim has given you a pretty good answer there.

      Again not my area of expertise and I was never very good at Physics but from what I’ve quickly read up on Jim is right. Our Sun is about 5 billion years old and should last for another 5 billion years. How this was worked out was by taking the amount of energy the sun has that can be turned into light and dividing that by the rate at which the sun is giving off energy.

      The total energy can be worked out using that famous equation of Einstein’s (E=mc2) and the amount of energy given off can be measured by seeing how bright it appears to us and knowing how far away it is from us. Pretty clever really!

      Like Jim said it will form a Red Giant then a white dwarf and engulf some of the nearby planets. But who knows where we will be by then, what evolution will have gone on. Will humans still be like us? Will we even still be on the planet? It would be nice to travel in time to find out!

    • Photo: Lizzard O'Day

      Lizzard O'Day answered on 16 Jun 2011:

      There has been a lot of activity on the Sun lately… just last week there was a major coronal ejection- basically the superhot plasma surface releases a massive burst of radiation- (google it- it’s really cool to watch). So as far as blowing up- it won’t- it’s actually not big enough so the chemistry just isn’t possible. The Sun is very slowly expanding.. this is because one of the ways the sun works is by burning the hydrogen in its core into helium. When the core runs out of hydrogen (we’re probably good for another 5 billion years) the reactions in the core will stop– but the reactions around the core will continue– this will make the core contract and as a result heat up… now the chemistry will change all over and the sun will begin burning helium into carbon at the core.. eventually the sun will also run out of helium– the core will again contract, but it will never be able to get hot enough to burn any other elements and the core will become a white dwarf star- where it will shine but not give off energy as it just slowly cools… the outer layers of the sun will become “planetary nebula”. Because the sun can never ignite anything past helium in its core- it won’t explode. We’re all OK (at least that’s that current theory).

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