The Earth's Spin Maintains its Direction in Space

The Earth acts like a gyroscope in its orbit around the sun in that it maintains the direction of its spin axis in space. The implication of the conservation of angular momentum is that the angular momentum of the rotor maintains not only its magnitude, but also its direction in space in the absence of external torque. Thus the axis and the northern hemisphere will be tipped toward the sun for part of the year (summer) and away from it at another time of year (winter). This is the cause of the seasons of the Earth.