Chapter 4 - Axis Tilt

The earths access is tilted at an angle of 66 1/2 degrees to the plane of the ecliptic and is always tilted in the same direction no matter where the earth is in its orbit. This constant tilt is key to seasonal change, as explained by the fact that around June 22 (summer solstice) the norther hemisphere is maximally tilted toward the sun, while 6 months later, around December 22 (winter solstice), the northern hemisphere is maximally tilted away from the sun. This accounts for the seasons of heat and cold, summer and winter.