Earth, Moon, Sun Vocab

2. something we observe to be similar over and over again
4. a moon phase that looks like a full circle from Earth
5. a moon phase that looks like half a circle from Earth
9. when the Moon is completely dark
10. a rocky sphere that travels around a planet
13. the star that is the main source of light at the center of our solar system
14. the sun, the planets that orbit the sun, and other objects that orbit the sun
16. a moon outside our solar system
17. a planet outside our solar system
19. the shape of the illuminated part of the Moon as it appears from Earth

1. a moon phase where the Moon is not visible from the Earth
3. to shine light on an object and make it visible
6. a moon phase that looks like less than a half circle from Earth
7. the border between light and dark on the Moon
8. an object, diagram, or computer program that helps us understand something by making it simpler or easier to see
11. the relative size of things
12. a moon phase that looks like more than a half circle from Earth
15. the amount of time it takes for a planet to complete one orbit around a star or stars
18. the nearly circular path a smaller object (like the Moon) travels around a larger object (like Earth)