2. Sphere A round solid figure whose surface is at all points equally distant from the center.

3. Axis The line around which an object rotates or seems to rotate.

4. Ellipse In space, an orbit that is not perfectly circular, but elongated like an oval.

5. Solstice An event that occurs twice a year in which the Earth’s axis points most toward or away from the sun. ( longest or shortest days )

6. Moon Phase A step in the journey around the Earth that the moon takes. Can be seen in 8 phases with varying amounts of light and dark.

8. Waxing The process in which the surface of the moon appears to be growing lighter. Right to left

9. Waning The process in which the surface of the moon appears to be growing darker. Right to left

10. New Moon When the moon is in the phase where the side facing Earth is completely dark. No illumination

11. First Quarter The phase in the lunar cycle in which the right half of the moon is illuminated.

12. Third Quarter The phase in the lunar cycle in which the left half of the moon is illuminated.

13. Solar Eclipse A process in which the moon passes between the Earth and the sun blocking the sun’s light from Earth.

14. Solar Eclipse

15. Lunar Eclipse A process in which the moon passes through Earth’s shadow.

16. Lunar Eclipse

17. Maria Dark spots on the surface of the moon. Caused by asteroids that struck the surface hard enough that lava seeped up and filled in the surface.

18. Equinox An event that occurs twice a year in which the Earth’s axis is halfway between the two extreme points. ( 12 hours of day and 12 hours of night )

19. Rotation The movement of an object around its axis

20. Revolution A body making one full lap around another body. Moon revolves around Earth, Earth revolves around Sun.