Eventually, the sun’s core will convert all of its hydrogen inside to helium and the star will die. But don’t sweat it. That won’t happen for about another 5 billion years.
The above is incorrect. Once the hydrogen is gone (or nearly gone) the Sun will contract until it's the heat and pressure are great enough to fuse helium into carbon. Then it will become a Red Giant.
You see the size of the Sun is controlled by a battle between the energy the Sun produces and gravity. The energy wants the Sun to expand, gravity wants the Sun to contract. When the Sun stops fusing hydrogen gravity takes control and the Sun contracts, in doing so it creates heat and pressure until the conditions allow for fusing helium into carbon. Then energy will once again expand the Sun turning it into a Red Giant. Sadly life on Earth will not survive this process. In fact life on Earth might not even be here to see it. The Sun get 10% more luminous every billion years. Yes global warming is for real and eventually it is going to kill us all.
