Across
- 2. tide when there is a first quarter moon
- 3. one of the planets with no moon
- 6. tide when the sun and moon are in line with earth
- 7. little "planets" ranging in size
- 9. two central points of an ellipse
- 14. once believed to be the centre of the universe
- 15. scientist who discovered gravity
- 16. symmetrically shaped oval
- 17. tide that occurs when gravitational forces work against each other
Down
- 1. pieces of space debris smaller than the smallest asteroids
- 2. large cloud of gas and dust floating in space
- 4. tide when coastlines are in line with moon
- 5. to revolve around
- 8. sixth planet from the sun
- 9. force that resists motion
- 10. tide occurs when coastlines are NOT in line with moon
- 11. man who formulated the three laws of planetary motion
- 12. asteroid-sized chunk of rock with a "tail"
- 13. time it takes for a comet to complete its orbit