The Sun will eventually swell into a red giant and shed its outer layers.

The longer version

Stellar evolution will eventually run the Sun out of hydrogen fuel in its core. With fusion slowing, the core contracts and heats while the outer layers expand enormously, turning the star into a cool but highly luminous red giant whose outer layers extend far past its present size. The Sun grows brighter long before this stage arrives.

Later, pulsations and radiation pressure blow the outer envelope away as a glowing planetary nebula, leaving behind a hot, Earth sized white dwarf that fades over billions of years. This fate is typical for stars of roughly the Sun's mass, though the timings span enormous stretches of time.

Where this entry sits

The night sky looks calm, yet almost everything up there is moving, burning, or slowly changing. These facts cover planets, stars, the Moon, gravity, black holes, comets, and the story of how people began exploring beyond Earth. The full list sits on the Space and Sky page, where every entry is listed in order.