Khan Academy
Khan Academy: Precession Causing Perihelion to Happen Later
Clarifies the effect of axial precession on the calendar and the date of perihelion and aphelion. [12:04]
Khan Academy
Khan Academy: What Causes Precession and Other Orbital Changes
Video lecture explores what causes precession and other orbital changes. [2:26]
Khan Academy
Khan Academy: Earth's Seasons Aren't Dictated by Closeness to Sun
Explains why Earth's closeness to the Sun does not dictate the seasons. [4:38]
Khan Academy
Khan Academy: Are Southern Hemisphere Seasons More Severe?
Are Southern Hemisphere seasons more severe because of the eccentricity in Earth's orbit? [7:17]
Khan Academy
Khan Academy: Apsidal Precession (Perihelion Precession) and Milankovitch Cycles
Learn how the Earth's tilt and rotation affect the Apsidal Precession (Perihelion Precession.) [7:06]