1. Eccentricity

2. Definition Degree of ovalness of an orbit around the sun

3. Ellipses ESRT Page Eccentricity = distance between foci length of major axis Foci- 2 points that are equidistant from center of major axis The sun is at one foci for our solar system Major Axis – line drawn through the 2 foci’s the long way 1

6. Ecc = distance between foci length of major axis = 2 cm 8 cm =.250 Which planets orbit is closest to this? Go to ESRT page 15 Mercury

7. Eccentricity of a Circle Foci coincide in the center, they are the same Ecc = distance between foci length of major axis Ecc = 0 cm 6 cm = 0

8. Eccentricity of a circle = 0 Eccentricity of a straight line = 1 All eccentricities will be between 0 and 1 There are never any units with eccentricity The greater the eccentricity, the more elliptical or ovally the ellipse is The lesser the eccentricity, the more circular the ellipse is