1 ESO

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Across
  1. 1. _Way, the name of our galaxy
  2. 7. _ layer, protects us from harmful solar radiation
  3. 8. The movement of a planet around the sun
  4. 10. When one celestial body blocks another
  5. 11. Equal to 3.26 lightyears
  6. 13. The process in which rocks change into other kids of rocks
  7. 15. The most abundant gas in the atmosphere
  8. 16. The way that a rock breaks
  9. 17. _ scale, used for measuring hardness
  10. 18. A type of igneous rock formed by magma cooling slowly inside of Earth's crust
  11. 19. The 2 days of the year when day and night are equal length
  12. 20. _ Effect, traps heat within Earth's atmosphere
Down
  1. 1. Earth's only natural satellite, it causes the tides
  2. 2. The gaseous layer that surrounds the Earth
  3. 3. huge groups of stars, nebulae, and dust held together by gravity
  4. 4. A type of harmful radiation from the sun
  5. 5. The movement of a planet spinning on its own axis
  6. 6. The outmost layer of Earth
  7. 9. The gas in the atmosphere that humans breathe
  8. 12. the lowest layer of the atmosphere
  9. 14. air_, alteration of air composition due to the presence of particles or energy