| A | B |
|---|
| astronomy | The study of the moon, stars, and other objects in space. |
| axis | The imaginary line passing through the center of an object and upon which it rotates. |
| rotation | The spinning of an object upon on its axis. |
| revolution | The movement of one object around another object. |
| orbit | The path an object follows as it revolves around another object. |
| latitude | The measurement of distance from the equator expressed in degrees north or south. |
| solstice | The day when the noon sun is directlyoverhead at 23.5 degrees north or south. |
| equinox | The day the noon sun is directly over the equator. |
| vernal equinox | Around March 21marks the beginning of spring in the northern hemisphere. |
| autumnal equinox | Around September 23 marks the beginning of fall in the northern hemisphere. |
| phases | The different shapes of the moon as seen from Earth. |
| eclipse | When an object in space comes between the sun and a third object and casts a shadow. |
| solar eclipse | When the moon's shadow hits Earth. |
| lunar eclipse | When Earth's shadow hits the moon. |
| umbra | The darkest, cone-shaped part of the moon's shadow |
| penumbra | The larger part of the eclipse shadow when the sun is partially visible. |
| tide | The rise or fall of water level depending upon the moon's pull. |
| gravity | The force between 2 objects dependent upon the masses and distance between the objects. |
| spring tide | A tide with the greatest difference between high and low tide. |
| neap tide | A tide with the least difference between high and low tide. |
| satellite | A natural or artificial object which orbits an object in space. |
| geosynchronous orbit | An orbit which makes a satellite appear to hover over a point on the object. |
| telescope | A device using lenses to make a distance object appear closer. |
| crater | A round pit. |
| maria | A dark flat area on the moon. |
