Movement in Space

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Across
  1. 4. A giant ball of superheated gas, or plasma, composed of hydrogen and helium.
  2. 6. The Greek philosopher who was one of the first supporters of the geocentric model
  3. 7. Another name for Earth's orbit around the Sun
  4. 8. Earth's only natural satellite
  5. 12. This comet first appeared in 1758 and continues to appear approximately every 75 years.
  6. 13. A pattern or group of stars that people imagine represents a figure, animal or object.
  7. 15. Stars are made up of hydrogen and _________.
  8. 17. During this season will you see the constellation Orion in the western sky
  9. 20. The word planet means ______________.
  10. 22. Earth-centered
  11. 23. Ursa major means ____________.
  12. 25. Pieces of space rock that hit the Earth's surface
  13. 27. This astronomer discovered moons around Jupiter, which showed that not everything in the sky travels around Earth.
  14. 28. Earth's revolution around the Sun causes __________.
  15. 30. Pieces of rock and/ice that have broken off of asteroids, comets, moons, and planets
  16. 31. A body that orbits a a planet.
Down
  1. 1. There are ____ constellations.
  2. 2. What Aryabhata used to come up with his ideas about how objects moved in space.
  3. 3. The astronomer who said the moon and planets shine because they reflect light from the Sun.
  4. 5. Proposed that Earth's rotation and revolution around the sun explained the observed movements of the stars and planets
  5. 9. Galileo discovered that this planet goes through phases like the moon does, meaning it must orbit the sun, not the Earth.
  6. 10. Sun-centered
  7. 11. Another name for a meteor.
  8. 14. The narrow band in the sky that contains the orbits of all the planets
  9. 16. In Ptolemy's geocentric model, the planets made small circles called _______ as they moved along their orbits.
  10. 18. Determined that the orbit of each planet is an ellipse rather than a perfect circle
  11. 19. An object that orbits the sun, is large enough to have become rounded by its own gravity, and has cleared the area of its orbit of any debris.
  12. 21. These two planets never appear far from the sun in the sky
  13. 24. Large, dirty space snowballs that develop a long tail of light as they approach the sun
  14. 26. An oval shaped orbit of the planets around the sun
  15. 29. Pieces of space rock that burn up as then move through the Earth's atmosphere.