Collected Illustrations of the Three Realms, Volume 4: Astronomy

Collected Illustrations of the Three Realms, Volume 4: Astronomy

Page 10

Externally, the Moon constantly receives the Sun's light to shine. Yet, among all physical things with form, none is without a shadow. Although the Earth is smaller than the heavens, it cannot be said to have no shadow. Since it has a shadow, the location of that shadow must necessarily be in direct opposition to the path of the Sun.

Because the Earth is situated exactly in the center of the heavens The text reflects the geocentric model common in Ming Dynasty China, where the Earth was viewed as the stationary center of the universe. while the Sun is attached to the celestial sphere as it moves, it follows that when the Sun is in the east, the Earth’s shadow must be in the west; and when the Sun is below, the shadow must be above. Since the Moon relies on receiving the Sun's light to shine, if its path encounters the Earth's shadow, there is no sunlight to receive. The Moon then has no means to produce light—how could it not be eclipsed? original: "shí" (食), literally "to eat" or "to devour," the traditional term for an eclipse.

In this way, we can see that the Dark Void original: "àn xū" (暗虛). In earlier Chinese astronomy, this was often described as a mysterious "invisible star" or "yin essence" that opposed the Sun. Here, the author identifies it scientifically as a shadow. is simply the Earth’s shadow. Furthermore, since it is the Earth's shadow, it is clear that its size is not limited to that of the Sun. If this were not so—given that sunlight shines everywhere—why would the "Dark Void," being in direct opposition to the Sun, be the only place the Sun's light does not reach? These are merely my speculative thoughts original: "yì duó" (臆度), referring to personal conjecture or subjective estimation rather than established canon. without definitive evidence, recorded here for the time being.