Simply put, it is because of the revolution of the earth that the four seasons alternate. The specific reason is that the formation of the four seasons is the result of the earth's revolution around the sun. The earth has been spinning from west to east, and at the same time it goes around the sun. The orbit of the earth's revolution is an ellipse, and the sun is always in a focus.

In the continuous revolution of the earth, the included angle between the earth axis and the revolution orbit is always 66 34', that is, the earth always revolves around the sun obliquely. Because of the revolution of the earth, the direct point of the sun changes on the surface of the earth.

Extended data

In the middle of winter, the sun's spirit retreats to the yin, life closes, and everything begins to harvest. "Autumn harvest and winter storage", everything is harvested in winter, and winter is the season to enjoy a bumper harvest and rest.

In many areas, winter means silence and desolation. When the cold current strikes, living things will reduce their life activities, many plants will shed leaves, animals will choose to hibernate, and some are called hibernation. Migratory birds will fly to warmer places for the winter.

Baidu Encyclopedia-The Revolution of the Earth