Planet Formation

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Across
  1. 2. Collision of asteroids on planets in the early solar system
  2. 4. A developing planetary body that grows by the accumulation of matter/material
  3. 6. sun, planets, and all the other objects that revolve around the sun
  4. 7. A gigantic explosion in which a massive star collapses and throws its outer layers into space
  5. 9. A process by which the gravity of an object compresses it, reducing the size and increasing density.
Down
  1. 1. the earliest stage of a star's life
  2. 3. The process by which two or more small nuclei fuse to make a bigger nucleus
  3. 5. a cloud of gas and dust in space
  4. 8. spinning mass of gas and dust from which stars and planets form