The next stage of the Sun's life cycle will be the red giant stage. Here's what will happen:
* Hydrogen Depletion: The Sun will eventually run out of hydrogen in its core.
* Core Contraction: Without the outward pressure from fusion, the core will begin to contract under its own gravity.
* Heating and Expansion: This contraction will cause the core to heat up significantly. This extra heat will cause the outer layers of the Sun to expand enormously, transforming it into a red giant.
* Helium Fusion: At the incredibly high temperatures in the core, the Sun will begin to fuse helium into heavier elements like carbon and oxygen.
This red giant phase will be a dramatic change:
* The Sun will become much larger: It will engulf Mercury, Venus, and likely Earth.
* It will become much cooler: Despite its enormous size, its surface temperature will be cooler, giving it a reddish color.
After the red giant stage, the Sun will go through several more stages, ultimately ending as a white dwarf.
