Extracted from Precessional Time and the Evolution of Consciousness, Inner Traditions, 2011. There is a long history of speculation concerning the origins of our Moon which is still not fully settled but an early impact seems most likely and a key proponent has been William K Hartmann of the Planetary Institute (also space artist, see below). The Moon has played so many important functions for the development of both the Earth and its Biosphere, that it is worth noting some of these when considering the Moon’s relationships to the synodic periods of the outer planets through its lunar year.
Over 4.5 billion years ago the inner solar system was a jumble of would be planets and planetoids. It is thought that Earth shared its orbital zone with at least one other planet about the size of Mars, similarly composed of a heavy metal core and outer mantle. Both would have been mopping up smaller bodies but eventually the two collided with each other.
Figure 1 The Collision of Earth and Thea (©William K. Hartmann)