| A | B |
|---|
| Autumnal Equinox | Sept. 22 or 23, when the number of hours of daylight and darkness are the same; first day of fall |
| axis | imaginary line through the center of Earth |
| equinox | when the number of hours of daylight and darkness are the same |
| revolution | one orbit around the Sun |
| Summer Solstice | June 21 or 22, the longest day of the year in the Northern Hemisphere |
| Vernal Equinox | March 20 or 21, when the number of hours of daylight and darkness are the same |
| Winter Solstice | Dec. 21 or 22, shortest day in the Northern Hemisphere; first day of winter |
| rotation length | one day, 23 hrs. 56 min. |
| revolution length | one year, 365 1/4 days |
| caused by Earth's rotation | day and night |
| seasons | caused by Earth's tilted axis & revolution |
| ellipse | shape of Earth's orbit |
| Earth's scientist definition of seasons | position of Earth in its orbit |
| Galileo | Italian astronomber who believed that the Sun was at the center of the universe |
| Incorrect Idea about Earth & Sun | Earth at center of universe |
