Earth's orbit around the sun is elliptical, with perihelion in early January when it is closest to the sun at around 1.5 million miles less than the average distance, and aphelion in early July when it is farthest at around 1.5 million miles greater than average. The two principal motions of bodies in the solar system are rotation, with the Earth rotating on its axis eastward over 24 hours to create day and night, and revolution around the sun over 365.25 days to complete one year.

1. Celestial Navigation ICapt. Bernabe LimINSTRUCTOR

2. Perihelion and Aphelion

3. PERIHELIONclosest point of Earth to sun

4. distance about 1.5 M miles less than the mean distance

5. occurs on early JanuaryAPHELIONFarthest point to sun

6. about 1.5 M miles greater than the mean distance

7. occurs on early July

8. MOTION OF BODIES OF THE SOLAR SYSTEMTwo principal motionsRotation

9. RevolutionVideo

12. ROTATION

14. ROTATIONRotation of Earth around axisRotates to EastTurns counter-clockwiseDaytime and night time24 hours or 1 day

15. REVOLUTION