Summary:
- When stars fuse helium into larger atoms, they become red giants.
- In a red giant, the inner helium core contracts while the outer layers of hydrogen expand.
- When the helium is gone, the stars become white dwarfs.
- A star like the Sun stops fusion and shrinks into a white dwarf star.
- A white dwarf is a hot, white, glowing object about the size of Earth.
- The Sun will become an enormous red star.
- It will grow so large that it will be out past Mars to the edge of the asteroid belt.