• 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.
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