Crossword

123456789101112131415161718192021222324252627282930313233343536
Across
  1. 1. the mean distance from the center of the earth to the center of the sun.
  2. 3. a unit of astronomical distance equivalent to the distance that light travels in one year
  3. 4. theory that suggests that the universe was created as a result of an extremely large explosion.
  4. 6. the smallest planet in the Solar System and the closest to the Sun.
  5. 7. a cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter.
  6. 12. a star showing a sudden large increase in brightness and then slowly returning to its original state over a few months.
  7. 13. a streak of light in the sky caused by a meteoroid crashing through Earth's atmosphere.
  8. 14. the fourth planet from the Sun and the second-smallest planet in the Solar System
  9. 15. the fifth planet from the Sun and the largest in the Solar System.
  10. 21. a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.
  11. 23. a very large star that is even brighter than a giant, often despite being relatively cool.
  12. 25. a closed plane curve generated by a point moving in such a way that the sums of its distances from two fixed points is a constant
  13. 26. the eighth and farthest-known Solar planet from the Sun
  14. 27. an eclipse in which the sun is obscured by the moon.
  15. 28. the planet on which we live
  16. 29. any theory of the structure of the solar system (or the universe) in which Earth is assumed to be at the centre of it all.
  17. 30. the systems of stars and interstellar matter that make up the universe
  18. 31. a small very dense star that is typically the size of a planet.
  19. 35. any natural solid object that survived the meteor phase in a gaseous atmosphere without being completely vaporized.
  20. 36. the branch of science which deals with celestial objects
Down
  1. 2. a planet that is composed primarily of silicate rocks or metals.
  2. 5. a small body moving in the solar system that would become a meteor if it entered the earth's atmosphere.
  3. 8. the changes in frequency of any kind of sound or light wave produced by a moving source with respect to an observer.
  4. 9. the sixth planet from the Sun and the second-largest in the Solar System
  5. 10. a minute planet; a body that could or did come together with many others under gravitation to form a planet.
  6. 11. any of the giant planets in our solar system
  7. 13. a continuous and distinctive band of stars that appears on plots of stellar color versus brightness.
  8. 16. the seventh planet from the Sun
  9. 17. having or representing the sun as the center, as in the accepted astronomical model of the solar system.
  10. 18. when the Moon moves into the Earth's shadow.
  11. 19. a star that suddenly increases greatly in brightness because of a catastrophic explosion that ejects most of its mass.
  12. 20. a very large star of high luminosity and low surface temperature.
  13. 22. frozen leftovers from the formation of the solar system composed of dust, rock, and ices.
  14. 24. a contracting mass of gas which represents an early stage in the formation of a star, before nucleosynthesis has begun.
  15. 32. a small rocky body orbiting the sun
  16. 33. the second planet from the Sun
  17. 34. a region of space having a gravitational field so intense that no matter or radiation can escape.