Question: As somebody with a PhD in Astrophysics, could you tell me roughly what will happen when the Sun dies?

Sam Geen answered on 17 Jun 2013:

The Sun will stop burning hydrogen in its core about 5 billion years from now. This will cause the core of the star to get colder and shrink. This will cause the energy from gravity to be given to the rest of the Sun, which will expand to engulf the inner solar system, including the Earth. Eventually all the material for burning will run out in the centre, and it will form a white dwarf, blowing the rest of the star out into a planetary nebula. A white dwarf is a small, dense dead star made of protons and electrons. The Sun is too small to explode – supernova explosions only happen to stars 8 times more massive than the Sun or so.