Crossword Puzzle: Models of the Universe

123456789101112131415
Across
  1. 3. center of the solar system according to Ptolemy
  2. 6. this scientists' model of the solar system finally explained the precession in Mercury's orbit
  3. 7. used Brahe's measurements to determine that orbits are ellipses
  4. 8. Kepler's 2nd Law: a planet sweeps out equal areas in ___ time
  5. 9. the location in an orbit farthest from the sun
  6. 10. Kepler's 3rd Law: The ____ squared equals the semi-major axis cubed
  7. 14. Tycho Brahe lost his ____ in a duel
  8. 15. This scientists' early model of the solar system only accounted for the planet's speeds
Down
  1. 1. popularizer of the heliocentric theory
  2. 2. the eccentricity of many comets orbits is nearly equal to ___
  3. 4. the location in an orbit closest to the sun
  4. 5. Kepler's 1st Law: Planets move in ___ with the sun at one focus
  5. 11. first theory of what makes planets go around the sun
  6. 12. ___ and epicycle: Ptolemy's mechanism for explaining retrograde loops
  7. 13. maade fantastically accurate measurements without a telescope