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 synodicThe recurring time cycle of a given celestial phenomenon seen from the Earth. 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)
In a vast explosion, the Earth was severely damaged whilst the energy released caused vast amounts of both planets’ surface rocks to be vaporised or projected whole into space. This caused a ring to form ar ound the Earth that quite rapidly accreted (consolidated) into a single body which soon cooled to form a Moon orbiting every 20 days, a mere 2700 Kms above the Earth’s surface. The planet that struck Earth has been called Thea after the goddess that gave birth to the Moon, the latter being called Selena in Greek myth. Meanwhile the metallic core of Thea was not absorbed by the Earth’s core but instead, significant metal deposits were embedded in the surface layers – a fact that gave the Earth a rich “wedding ring” of workable ore deposits, significant to the later metal-working ages.
Such a massive satellite travelling over the Earth caused the whole surface to gravitationally deform below the Moon, but the Earth was then rotating every six hours so that this bulge would always be ahead of the Moon. Just as with tides today, but then much more strongly, the Earth’s rotation transferred energy to the Moon causing it to accelerate and take an ever-higher orbit. However, this was not before the Moon had kneaded all the surface rocks. This type of lunar influence then continued in an unusual way.
Around 4 billion years ago, the orbits of Jupiter and Saturn aligned so as to create a slingshot for solar system bodies that had not yet been incorporated into planets. This Late Great Bombardment proceeded to strike the Moon rather than the Earth and this protective role is thought to have saved Earth from damage to its nascent resources, such as the water present on its surface. The recognisable face of the Moon was largely created at this time, as craters and “seas” of molten basalt from this bombardment.
The Moon was further accelerated to an orbital distance of 320,000 Km by 3 billion years ago and this meant that its tidal effects were no longer strong on the mantle rocks but instead, the seas of that period experienced massive tides, hundreds of meters high. These must have been like continuous tsunamis racing around the globe. Meanwhile, due to the still great rotational speed of the Earth, these tides occurred many times a day and also, the early atmosphere was whipped up by the Coriolis effect so as to create continuous, hurricane speed winds. The extreme ocean tides caused massive erosion and mineralisation of the seas forming a massive number of chemical scenarios that could even have been responsible for the creation of life in the form of primitive replicating molecules.
Even today, volcanoes and Earthquakes are thought to trigger eruptions and release of seismic energy built up in the Earth’s unique tectonic plates. These plates themselves could be an artifact, in part, of the Moon’s kneading of the Earth and we can see that on Mars, any plate activity ceased billions of years ago as the mantle became stuck to a solidified core – probably through lack of a large Moon.
Whilst the original collision almost certainly caused the high spin of the Earth, it also created the tilt of the axis on which the Earth rotates. This tilt set up the seasonal conditions on Earth, so important for life’s varied habitats. However, this tilt would not have been stable without the large Moon that also resulted. Our large Moon stabilises the tilt by shielding the Earth from the small chaotic forces the Earth experiences due to the other planets. Mars is particularly vulnerable, and its tilt varies over millions of years by about 30 degrees. The Moon, by adding a large systematic component to the precessional forces, prevents planetary chaotic resonances from affecting the Earth.
The effect of the seasons, maintained by the Moon, is joined by the extra tidal effect it has on the seas and oceans. These tides create an extensive area of a very important habitat within the tidal ranges found on our coastlines. These are very bio-diverse and also have led to evolutionary changes as significant as the adaptation of marine animals into land animals.
In summary therefore, life on Earth would not have been possible without the Moon and the very special itinerary of its genesis and the gradual arrival at the conditions we find today. It all seems a little too special and this has lead to the general recognition that life such as found on Earth could not have evolved without such a special collision occurring at exactly the distance from the Sun capable of supporting such life. The precessional mechanism would not be stable without the Moon.