Annual Yin-Yang Time Model

The first model to appear is the annual Yin-Yang time model. It applies the Yin-Yang binary framework to the yearly cycle. In this presentation, the Yin and Yang discussed by the ancients are given a very concrete physical definition: on the annual scale, yang qi refers to the radiant energy produced by the Sun, this enormous star—solar radiation. When that radiant energy is blocked, for example by clouds or shade, the condition is physically Yin; when the radiation shines directly, it is Yang.

The annual waxing and waning of solar radiation is the most intuitive physical basis for this Yin-Yang time model.

The Earth’s revolution around the Sun produces annual sinusoidal variation in incident angle and daylight duration. If data from a Clear Sky Model, with cloud interference removed, are averaged and plotted for every day of the year, one obtains a smooth, symmetrical, wave-like curve. In geometric form, this curve is argued here to closely resemble the boundary between the Yin and Yang “fish” in the Taiji diagram. The Western habit of sunbathing while on holiday to “replenish yang qi” can, in this interpretation, be understood as a natural health practice aligned with the annual Yin-Yang time model. As the proportion of modern people suffering from depression increases, solar radiation is also presented as one means that may help relieve disorders of mood.