Earth, Moon and Sun

2. when the moon is completely dark
4. the sun, planets that orbit the sun and other objects that orbit the sun
5. the relative size of things
6. a moon phase that in which the moon is not visible from earth
10. a planet outside our solar system
12. an object,diagram or computer program that helps us understand something by making simpler or easier to see
13. the star that is the main source of light at the center of our universe
15. a sphere that travels around a planetcrescentmoon a moon phase that looks like less than half a circle from earth
16. a moon phase that looks like a full circle from earth
17. the shape of the illuminated part of the moon as it appears from the earth

1. a moon phase that looks like more than a half circle from earth
3. a moon phase that looks like a half a circle from earth
7. a moon outside our solar system
8. the amount of time it takes for a planet to complete one orbit around a star or stars.
9. something we observe to be similar over and over again
11. the border between light and dark on the moon.
14. to shine light on an object and make it visible
18. the nearly circular path a smaller object (like the moon) travels around a larger object (like earth)