• Question: why do stars explode

    Asked by anon-267423 to Zsolt on 26 Nov 2020.
    • Photo: Zsolt Keszthelyi

      Zsolt Keszthelyi answered on 26 Nov 2020:

      That’s a good question. This has to do with ‘why are stars in balance?’ and how they get out of this balance.
      So, stars are in balance because there is fusion in the core, producing energy. This energy pushes matter away. But gravity tries to do the opposite, bringing all the matter together. These two work to balance out each other.
      Stars, when massive enough, can indeed explode when this balance is lost upon running out of fuel to produce energy. (Note that the Sun and such stars will not explode, they will simply cool off – with a new source of energy helping to balance.)
      In massive stars, there cannot be enough energy to balance gravity, and the core collapses. This collapse leads to dropping off the outer layer of the star. This is known as the supernova event. Then the centre becomes a compact object, which is either a neutron star or a black hole.