AST Chapter 9 CROSSWORD REVIEW

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Across
  1. 2. The fine, powdery dust on the Moon's surface, resulting from impacts.
  2. 3. Dark, younger, roughly circular regions on the Moon, formed by lava flows.
  3. 7. The gaseous envelope Mercury and the Moon lack.
  4. 10. Theory that the Moon formed elsewhere and was snagged by Earth's gravity.
  5. 12. Large impact basin on Mercury.
  6. 13. Planet closest to the Sun, heavily cratered like the Moon.
Down
  1. 1. Material thrown out from an impact.
  2. 4. US program that landed astronauts on the Moon.
  3. 5. Property relating mass to volume; Mercury's is very high.
  4. 6. General term for a hole excavated by a rock hitting a surface.
  5. 8. The older, lighter-colored, heavily cratered regions of the Moon.
  6. 9. The type of impact theory currently favored for the Moon's origin.
  7. 11. Long cliffs on Mercury, indicating the crust shrank.