Thursday, August 10, 2006

The 4 elements: fire fire burning bright

There is nothing like fire under the ocean. This may sound pretty stupid but it is of interest when you consider the evolution of life and of civilisation.

First - what is fire? It is a rapid and runaway oxidation reaction which releases energy and consumes local fuel until it is exhausted.

Why can't we have fire under the ocean? Well in fact we can - there are certain chemicals which when mixed and subjected to ignition will commence a runaway oxidation reaction. But these chemicals do not occur naturally, as does wood and air.

There is another exception to this point which I feel I should also address. By stretching the definition a little we could perhaps say that life (which is a heavily modulated oxidation reaction) is itself a type of fire.

And by stretching the definition of fire in this way to include life I have actually managed to refute my first assertion. Life evolved in water and life does exist in water. Please bear with me.

Why do we have fire in our world? A good way to think about this question is to ask - what burns? And when you think about it - life burns. Before life left the oceans there was nothing - no oil, no wood, no people - to burn. So the modulated oxidation reaction called life that began in the oceans evolved up and onto land and carried with it oxidisable material to where it could burn. Thus fire.

It has been argued that life is only likely in places where liquid water can exist. This is because water is a unique molecule, whose electromagnetic properties are predisposed to generation of complex surfaces, films and structures, among many other specialities. This generative nature of water give rise to a wildly heterogenous environment of liquids, solids and gases and it for this reason (the argument goes) that life formed on earth.

Could we argue that water gives rise to fire?

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