Deep inside the core of a Star a war wages against gravity – the larger the Star, the more intense the battle. It is locked in a constant state of producing energy to push against the Star collapsing in on itself under the sheer weight of its own gravity (if you can attempt to imagine such a thing). While there is still Hydrogen burning to Helium in the core, energy is produced and creates an equal pressure against the gravity.
So what happens when the Hydrogen runs out?
As the Hydrogen fades the pressure holding up the gravity will weaken and the core cools very quickly, leaving an outer shell of Hydrogen and Helium that has been pushed to the surface. As the gravity collapses this causes the core to rapidly heat up once again, and at 100m degrees Helium nuclei will fuse together.
This will cause further energy to be released and stops its own collapse once again, this time Carbon and Oxygen are produced. The larger the Star, the longer the fusion can carry out its reaction. As the energy runs out again, the collapse will happen again and as the temperature rises further, elements such as Magnesium, Neon, Sodium and Aluminium are produced.
This fusion process will continue inside the Star’s core going from one element to the next until it has burnt through all the elements we know.Finally, after everything has been burnt the Star will turn into pure Iron and this is when the fusion will stop. Each of the elements will be stacked on top of eachother in layers ending with Hydrogen, Helium, Carbon, Oxygen and so on.
Within seconds – bang.With no energy left holding its weight, the sun will collapse and turn into a Supernova.
Could this happen to our Sun?
It will, but not anytime soon. Our Sun will still take a very long time to die however, it is worth turning out attention to one of the nearest Star – Betelgeuse, located in the constellation of Orion.
Only 600 light-years away, Betelgeuse is a Red Giant (a dying Star) and could Supernova any day between tomorrow and the next million years. It will shine with the power of a thousand Suns and will appear about the size of our Moon!
Betelgeuse, according to Scientists, has dimmed about 15% in the last 10 years.
Does this spell the end of life if Betelgeuse explodes?
Probably not – I will cover this topic more on another day but it is certainly not anything we need to start worrying about.