| A | B |
|---|
| day | the length of time it takes a planet to spin around once on its axis |
| year | the length of time it takes a planet to orbit the sun |
| rotate | to spin on an axis |
| axis | An imaginary line that runs through the center of Earth from the North Pole to the South Pole |
| season | The tilt of the Earth and the constant movement around the sun cause this |
| revolve | to travel in a closed path |
| orbit | the closed path of one object in space around another object; or to move in such a path |
| satellite | An object that moves around another object in space |
| moon | A natural body that revolves around a planet. |
| phase | One of the shapes the moon seems to have as it orbits Earth. |
| waxing | The moon's phases get bigger. |
| waning | The moon's phases get smaller. |
