The Sun

The Sun is what makes Earth the perfect temperature so it can be habitable. Humans normally go to sleep when the sun comes down and Luna appears, depending where you are on Earth. When humans become a Type II Civilization on the Kardashev Scale, they will build a Dyson Sphere around the sun and get all of its energy. The sun is so hot, that it’s surface is the same temperature as the Earths core.

The sun will get colder in 2030. Eventually, in 4B A.D The sun will run out of fuel and burn out, then turn into a Red Giant. It will expand and suck up Mercury and Venus, and maybe even Earth. Then it will turn into a White Dwarf the size of Earth a long time after that.