science(space)

12345678
Across
  1. 2. has 27 moons
  2. 4. sunsets are blue
  3. 6. first artificial satellite in space
  4. 7. is third planet in solar system
  5. 8. is completely silent
Down
  1. 1. hottest planet in solar system
  2. 3. second most largest planet in our solar system
  3. 4. first spacecraft visited mercury in 1974
  4. 5. is not an empty space
  5. 8. twinkle at night