• Question: will the sun burn out and if so when is it estimated to burn out?

    Asked by 477smgd54 to Natalie, Aaron, Pete, Keith on 13 Nov 2015. This question was also asked by barakat.
    • Photo: Aaron Boardley

      Aaron Boardley answered on 13 Nov 2015:

      The sun will run out of fuel eventually – but it’s pretty huge, so it has enough to keep going for another 5 billion years!

    • Photo: Peter Burgess

      Peter Burgess answered on 13 Nov 2015:

      … and when it does eventually die, it will become a white dwarf.
      There are a few different kinds of dead and dying star and the end stage of a star’s life is basically determined by its mass.
      At the moment, the sun is balanced between its gravity which is trying to collapse it inwards, and the nuclear fusion reactions at its heart which are trying to blow it apart.
      As a star gets old, the process of fusion loses its strength and eventually ceases. At this point, the star’s gravity has nothing to fight it and so the material collapses inwards.
      For a star like the sun, eventually the atoms in the star can no longer squeeze more tightly together and the star dies as a white dwarf.
      With a heavier star, the collapse can continue as the atoms are squeezed together by gravity and the electrons around the nuclei are forced inward and they combine with the protons to form neutrons. These are neutron stars which weigh more than the sun but are so dense they are only about the size of a city.
      And as I guess you might know, the heaviest stars don’t even stop there but keep going to form a black hole.

    • Photo: Natalie Garrett

      Natalie Garrett answered on 13 Nov 2015:

      It will burn out, but not for ages (as the others have said). I am hopeful that people will have started colonising other planets in other solar systems before that point, so that people can watch the planet earth’s impending doom on a screen somewhere and toast to humanity’s first (but not last) home.