Could We Exist On Earth Under A Red Giant Star?

About five billion years from now, the Sun’s usual source of nuclear energy will be depleted. It will begin to expand and cool significantly, becoming a ‘red giant’. Its outer layers will be thrown off into space.

As the Sun loses mass, its gravitational pull will weaken and the planets’ orbits will widen. We know that Mercury and Venus will not be able to outrun the expanding Sun, and will be engulfed and incinerated.