| A | B |
|---|
| astronomy | the study of the moon, stars and other objects in space |
| rotation | the spinning motion of a planet about its axis |
| axis | an imaginary line that passes through Earth's center and the North and South poles, about which Earth rotates |
| revolution | the movement of one object around another object |
| orbit | one complete revolution around the sun |
| ellipse | shape of a planet's orbit around the sun |
| length of Earth's revolution around the sun | 365 and 1/4 of a day |
| February | month in which one day is added every 4 years due to Earth's revolution |
| seasons are because... | the Earth's axis is tilted as it moves around the sun |
| solstices | Season in late June and December in the Northern Hemisphere |
| equinoxes | Season in which the sun shines directly above the equator |
| latitude | a measurement of distance from the equator, expressed in degrees north or south |
| vernal equinox | occurs in the spring |
| autumnal equinox | occurs in the fall |
| phases | the different shapes of the moon you see from Earth |
| 27.3 days | the amount of time that the moon rotates on its own axis |
| Earth's calendar year | 365 days or 366 on leap year |
| longitude | measure of distance from East to West from the prime meridian |
