It was some years ago whilst reading some of Robert Bauval and Graham Hancocks work that a thought occurred to me. In one particular book (Keeper of Genesis), they were discussing how precession or the wobble of the Earths spin can mean that the position of constellations etc. in the night sky or for that matter the Suns position can vary over a period of thousands of years.
This had me wondering; why does the Earth wobble?
Then I found myself thinking about the formation of the Solar System, some 4.5 billion years ago.
It is a well accepted theory that at this time, the Earth and all the planets, in fact, were forming by the gravitational force of the Sun, and were probably just balls of gases that also due to gravity were spinning and gradually condensing into more solid objects.
At some stage during this period, when the Earth was but a ball of molten material, it is thought that it was in collision with another object that bounced off into space and – caught in the Earths gravitational field – went on to become what we now know as the moon, as first put forward by a certain Reginald Daly.
My proposition largely depends on when this event occurred. Its just possible that it was at the stage when the Earth, although still a spinning sphere of mainly molten rock and iron, was solidifying at its centre or core.
What if a part of this other object had remained embedded in the Earths outer mantle which at the time would have been partially molten and like some massive carbuncle that gradually sunk and coalesced with the Earth, then by centrifugal force, spread and flattened out?
To quote from Wikipedia s article, History of the Earth:
One very large collision is thought to have been responsible for tilting the Earth at an angle and forming the Moon.
Yes, this would explain the tilt but it would also explain the Earths wobble. Imagine this great spinning ball, whether tilting or vertical, being thrown out of balance by a mass of foreign material probably somewhere near the equator.
This mass of material would, in the space of about a billion years or so, go on to become the single continent of Pangaea
This in turn would, again by centrifugal force and the movement of plate tectonics, slowly break up to become the major continents that we know today. (For more on this see the afore-mentioned Wikipedia article).
It might be right to assume that as the continents distributed themselves more evenly that the Earths precession, or wobble, would gradually decrease in time but this seems to be in dispute.
In fact it has been suggested that precession is variable; that it waxes and wanes although, as the period of this wobble completes its cycle every 26 thousand years, it may be rather difficult to prove either way.
It should be noted that the Earth is apparently the only planet that suffers from plate tectonics. I wonder if it is the only one that is prone to precession also.
In conclusion, I would like to know why, after much searching, have I not come across a similar conclusion i.e. that the Moon, as it now is, was the reason that gives our planet her unique properties. This is further supported by the fact that the Moon consists mainly of material from the Earths crust, with very little iron in its constituents. Or to summarize: Earth/Moon collision> singular residue of Moon causing precession and potential for a land mass> life on Earth.
It all leads one to speculate as to whether the, literally, earth-shattering events discussed above enabled our planet to support the diversity of life that she does or indeed whether, had not this momentous collision occurred, would there be any form of life here at all?
I am no more a geologist than I am a scientist, Im merely proposing a theory that no one to my knowledge has put forward before and I would be grateful for any comments about these ideas in the comments box below.