Powered by the Sun

12345678
Across
  1. 2. The Sun is expected to shine for ___ billion more years.
  2. 3. The sun's energy.
  3. 5. Nuclear fusion makes a lot of _____.
  4. 6. Energy source that formed over millions of years from the remains of plants and animals.
  5. 7. Solar panels were put here in 1977.
  6. 8. First office building in the world to be heated with solar energy.
Down
  1. 1. Something that can be replaced.
  2. 4. Native Americans created passive solar homes in cliffs.