World of Physics

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Across
  1. 6. neutron and ______ are help together by mesons?
  2. 7. a group of millions to billions of stars help together by mutual gravity.
  3. 9. it was invented to Save the conservation of energy.
  4. 10. science consist of Scientific theory and ____________?
  5. 15. what is the opposite charge of a proton?
  6. 17. a big things that went around a sun and moons were anything that went around.
  7. 19. a no longer consider planet.
  8. 20. Quarks are held together by what?
Down
  1. 1. Cloud comets froze a huge spherical cloud far outside of the Kuiper belt.
  2. 2. closest planet to the sun.
  3. 3. My teacher calls himself.
  4. 4. hole a star that crush with great gravity.
  5. 5. rocks going around space.
  6. 8. system consist of things that go around a Star.
  7. 11. result from a runaway thermonuclear reaction.
  8. 12. something lots smaller than atom.
  9. 13. a heavy electron.
  10. 14. a generic name for electrons and their relatives.
  11. 16. something can can never be prove___________?
  12. 18. dark matter, star, and what make up a galaxies.