| A | B |
|---|
| Aphelion | The furthest point the Earth reaches while orbiting the sun |
| Perihelion | The closest point the Earth reaches while orbiting the sun |
| Ellipse | A slightly irregular circle |
| Eccentricity | A measure of the severity of an ellipse |
| Foci | The points found in the center of an ellipse |
| Major Axis | The longest line that is drawn through the foci of an ellipse |
| Revolution | The movement of the Earth around the sun |
| Rotation | The movement of the Earth around its axis |
| Heliocentric | A model of the solar system with the sun in the center |
| Geocentric | A model of the solar system with the Earth in the center |
