In about six billion years our sun is expected to dramatically expand and grow hotter as its helium core contracts and ignites the outer layers of hydrogen, eventually becoming a type of star called a "Red Giant."
In this image the Sun has just started its journey toward becoming a Red Giant, however the intense heat has already boiled off Earth's oceans and driven away most of the atmosphere leaving a lifeless, molten surface.
The Sun will continue to bloom for the next few hundred million years until it fills the sky and eventually engulfs the Earth
entirely.
The Earth was born of fire, and fire will be its end.