Astronomy Crossword

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Across
  1. 3. a star that suddenly increases greatly in brightness because of a catastrophic explosion that ejects most of its mass
  2. 4. a property of matter by which it continues in its existing state of rest or uniform motion in a straight line
  3. 6. a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction
  4. 7. Who discovered gravity?
  5. 8. the center of our solar system
  6. 9. the third planet from the sun
Down
  1. 1. an invisible force that attracts a body toward another body of mass
  2. 2. the fifth planet from the sun
  3. 5. plant where we live
  4. 7. cloud of dust and gas where our solar system created