1. 2. A power that keeps planets orbiting the sun
  2. 5. A gravitationally bound system of starts, stellar remnants, interstellar gas, dust and dark matter
  3. 9. A satellite orbiting the Sun, may go really far away from the Sun and return after hundreds or thousands of year. Some contain water ice.
  4. 12. The biggest planet of the Solar system
  5. 14. Last name of the man who did the first spacewalk
  6. 15. Eighth planet from the sun
  7. 16. A natural satellite orbiting Earth
  8. 17. The center of the Solar system
  9. 19. A star system consisting of two stars orbiting around their common barycenter
  10. 20. Third planet from the Sun
  1. 1. The biggest galaxy of the Local group
  2. 3. The smallest planet of the Solar system
  3. 4. The planet with least density on the Solar system
  4. 6. A circumstellar disc between planets Mars and Jupiter that contains asteroids, minor planets and debris
  5. 7. The fourth biggest moon in the solar system. Has a lot of volcanoes.
  6. 8. Number of the Apollo flight that landed to the Moon
  7. 10. Second biggest galaxy of the Local group
  8. 11. Number of moons orbiting planet Mars
  9. 13. Second planet from the sun
  10. 18. The biggest moon orbiting Saturn