Gravity and the Universe

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Across
  1. 1. when gas and dust clump together they form
  2. 5. this type of galaxy is oddly shaped
  3. 8. this type of galaxy has a higher percentage of old, red stars
  4. 13. this type of galaxy has circular arms and begins at the central disk
  5. 14. Nicholas Copernicus proposed that Earth and other planets revolved in circular orbits around the sun called ___ model
  6. 15. is an attractive force that exist between all objects that have mass
Down
  1. 2. Johannes Kepler discovered that planets' orbit is not circles but this
  2. 3. the more mass either object has or closer together they are the strong the ___
  3. 4. meteoroids, _____, and comets orbit the Sun in their own paths through the solar system
  4. 6. huge collections of gas, dust, and stars held together by gravity
  5. 7. solar system formed from a rotating cloud of gas, ice, and dust is called ___
  6. 9. ____ orbit the sun in the asteroid belt
  7. 10. ____ are equal distance from the ellipse's center
  8. 11. the process that occurs when the nuclei of several atoms combine into one larger nucleus
  9. 12. we live in what galaxy