| A | B |
|---|
| winter solstice | Day when the North Pole is tilted 23.5 degrees away from the sun |
| summer soltice | Day when the North Pole is tilted 23.5 degrees toward the sun |
| autumnal eqinox | September 22 or 23 in the Northern Hemisphere |
| vernal eqinox | Day on which Spring begins |
| magnetosphere | Earth's magnetic field |
| solar wind | stream of electrically charged particles blowing from the sun |
| aurora | bands or curtains of shimmering colored lights caused by solar wind particles coming in contact with atmospheric particles |
| Van Allen Radiation Belts | doughtnut shaped region of charged particles surrounding the Earth |
| rotation | the time it takes for a planet to make one complete turn on it's axis |
| revolution | the time it takes for a planet to make one complete orbit of the sun |
| leap year | every four years |
