Across
- 1. showed mathematically that the planets revolved in elliptical paths around the sun
- 3. wrote the three laws of motion that explained gravity and inertia, invented calculus
- 4. the imaginary line passing through both poles and the center of a planet
- 6. the path a planet takes as it orbits once around the sun
- 8. added to Aristotle's idea by explaining the movement of the planets as little circles on their spheres
- 9. used a telescope to study astronomy
- 12. stated that the Earth was still and was the center of the universe
- 13. first to write a book about a sun-centered solar system
Down
- 2. the spinning of a planet around its axis
- 4. tilt 23.5 degrees for Earth
- 5. a force that attracts one object to another
- 7. sun centered
- 10. Earth centered
- 11. a property of matter that states that still things remain still, moving things keep moving, unless acted on by a force