| A | B |
|---|
| rotation | the spin of a body on its axis |
| year | the time required for earth to orbit once around the sun |
| solstice | the point at which the sun is as far north or as far south of the equator as possible |
| day | the time required for earth to rotate once on its axis |
| season | a division of the year that is characterized by recurring weather conditions and determined by both earths tilt relative to the sun |
| revolution | the motion of a body that travels around another body in space; one complete trip along an orbit |
| equinox | the moment when the sun appears to cross the celestial equator |
| satellite | a natural or artificial body that revolves around a celestial body that is greater in mass |
| eclipse | an event in which the shadow of one celestial body falls on another |
| gravity | a force of attraction between objects that is due to their masses |
| umbra | a shadow that blocks sunlight, such as the conical section in the shadow of the earth or the moon |
| lunar phases | the different appearances of the moon from earth throughout the month |
| penumbra | the outer part of a shadow such as the shadow cast by Earth or the moon in which sunlight is only partially blocked |
