Last article I said that I would be looking at multiple moons. However, I since realised that before that I should really establish the basics and look at how our own Moon effects the Earth and even ourselves.

The most readily understood effect our moon has on the Earth is its contribution to the tides of the Earth’s oceans. The gravitational attraction of both the Sun and the Moon on the fluid structure of water creates tides in all bodies of water, but it is significant that only in the oceans does this effect become noticeable.

    The Bay of Fundy at both high and low tide.

Images courtesy of WikiMedia Commons.

In smaller bodies of water the effect is too small to register or is lost amid the background fluctuations caused by the weather. To put this into numbers, it has been calculated that the rise and fall of the water in the North American Great Lakes due to the tides is 1 to 4 cms.

It is important to note that same forces acting on the atmosphere produces negligible effects (and yes, there are atmospheric tides — why wouldn’t there be?). It is my belief that the strength of the tidal effect is mainly due to a special property of water — its electrically polar nature which gives it a strong surface tension. As a corollary of this, if you have a planet that has oceans of a fluid other than water, then perhaps there would be little or no tidal effect, with or without a moon. Can’t give any references here, as this is just supposition, but I would welcome any comments on this.

The Moon effecting the brain, that’s lunacy!

I said before that the Moon created tides in all bodies of water. The human body is made up of between 55 and 78 percent water (dependent on body size). So, does the Moon have an effect on humans? I suspect, given the gravitational effect on the Great Lakes mentioned above, that there is not a measurable physical one. But what about other effects?

The scientific community is generally against the idea of non-measurable causal effects (see the sceptics reference below), and these abound for the effects of the Moon on people. For myself, I have spent far too many nights of the full moon unaccountably awake with insomnia not to think that there is indeed some effect at work. However, before people start talking about Lycanthropy, I suspect we should look at our own internal biological clocks first.

Our body is ruled by them — these internal biological clocks — and the master clock in the brain is set by the light patterns of night and day. The Moon is the second brightest object in the heavens after the Sun. Is it hard to imagine that the bright light from a rising full moon — which is not only highly noticeable, but enjoyable to view — might cause upset to our biological clocks and send our hormones out of balance for the night?

This is of course all pure speculation on my part, but I will leave it up to my readers to speculate on what a planet with more than one large moon would suffer more from such lunacy, or less.

Next week I will be searching further afield to find other effects that moons can have on their parents.


More about the tidal phenomena of the Great Lakes

The chemical and physical properties of water

Water in the human body

The sceptic’s dictionary on the effects of a full moon.

N.B. Please note that I although I use the Wikipedia (and WikiMedia Commons) a lot for references, this is for expediency and the familiarity of my readers. Anyone interested in further studies should make use of the references where available and understand that the Wikipedia is a co-operative project contributable to by anyone and must always be looked at in that light.

Phill Berrie, September, 2008.