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Tides and Time

30 March 2013

At http://phys.org/print282764868.html … the question is what kick started life on Earth. It recognises the possibility of panspermia but on this occasion its interest is on terrestrially based origins for life, and in particular looks at the role of the Moon on life.

The Moon, it is thought, was very much closer to the Earth at one time, and if so tides would have been far greater than they are today. Days were shorter and tides washed in and out with a greater frequency – and may have created large tidal areas on the boundaries of the oceans with the continents. Life from mud and muck. Various authors see such tidal areas as a catalyst to the necessary chemical reactions to set life in motion. The article then discusses Ward and Brownlee's book, Rare Earth: Why complex life is uncommon in the unviverse' (2000) which argues that planets like the Earth, hosting complex life, are incredibly rare (but we don't know that, do we?)

The oceans are said to contain the necessary organic molecules for life – or they might have been delivered by radioactive decay (one theory). How such molecules went on to become life is itself intriguing – but the argument here is that without the Moon the tides could have been much slower (due solely to solar influences) and this might have inhibited the development of life. Without the Moon, they argue, Earth's axis would have varied greatly, and chaotically, ranging from almost no tilt at all through the present tilt position to the the planet tipped over on its side (or even all the way over, perhaps, although that is not envisaged here). For example, the axial tilt of Mars is thought to vary between 0 degrees and 60 degrees, over a suitably long period of time, solely as a result of perturbations from the other planets. They say this renders the planet inhospitable to complex life – an interesting idea. It also assumes the Moon has been ever present.

The hypothesis that the Moon is required to stabilise Earth's axis is just that, an idea, we learn, an idea that has become lodged within mainstream. It seems that if the Moon was just a bit larger, by around 10km in breadth, or a third of 1% of its diameter, Earth's axis would become unstable, driving a hugely chaotic motion. This is an incredible admission – and many other authors, it seems, have admitted this might be so, and yet the mantra remains.

So, although it is still the consensus that the Moon stabilises the axis is this really cast-iron, stuck together with super glue, can't be breached theory? A Moon that was closer would itself have loomed larger and might this in itself have caused tilt – quite apart from any other factor (as yet not appreciated). It seems another consensus article of faith, the Earth has not moved on its axis, might all be just poppycock – an embedded assumption.

However, at the same time the Moon clearly does play an extraordinary role on life on Earth, as noted by Klaus-Peter Endres and Wolfgang Schad, in their book, Moon Rhythms in Nature: How lunar cycles affect living organisms (Floris Books of Edinburgh, 2012, but the German edition was in 1997). Chapter 3 actually has the title 'Life on Tidal Coastal Areas' and is a fascinating read – everything from worms to fish, eels to owls, insects and honeybees.

Chapter 9, 'The Quality of Time' is also quite interesting as it makes the point that rhythms in nature are similar (to the one before) but not the same (and yet is not completely different either). Reason allows us to understand what being simialr means but the intellect does not. The intellect would prefer a clear difference between the same and what is different – either one thing or the another. Living rhythms are never exactly the same as themselves but always flow into something new as well as into its origins, thus changing them, (and so on).

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