Explosives are usually associated with death, not with life. But more or less the same chemical elements are involved in explosion reactions and in life reactions: carbon, hydrogen, nitrogen, oxygen, and perhaps phosphorus and sulfur (abbreviated to CHNOPS). Gunpowder consists of saltpeter (containing nitrogen and oxygen), charcoal (carbon), and sulfur. The mixture burns as the carbon and sulfur avidly react with oxygen. Nitrogen in the form of nitrate (in saltpeter) provides a source of loosely bound and concentrated oxygen. The mixture burns quietly if unconfined (no pressure), but explosively when confined.

Yet gunpowder is only a mixture, and the three ingredients cannot be mixed intimately enough. In high explosives, all the necessary chemical elements are contained in the same compound, so that they can interact at a molecular level. Nothing can be more intimately mixed. Nitrocellulose (guncotton), nitroglycerine, and TNT (trinitrotoluene) contain the CHNO needs of powerful explosions. (S and P are not really necessary.)

In aerobic life forms energy metabolism consists of combining carbon-hydrogen-containing compounds (sugars and fats) with oxygen, through initial glycolysis followed by the Krebs cycle taking place in mitochondria, all the way through to carbon dioxide and water. (If proteins are metabolized, there is nitrogen and sulfur as well, but the fate of these elements need not concern us here.)

Explosions and metabolism essentially involve similar reactants and identical final products. The main difference is the rate of the oxidation reactions. Both involve “burning” of organic compounds to the most stable free energy compounds, carbon dioxide and water. However, the reactions proceed very rapidly in explosions, since the drop in free energy is very large, and when all obstacles are removed, events proceed very rapidly, as in a waterfall or a lightning bolt. In the metabolism of living cells, on the other hand, the “burning” is slowed down by making it proceed through a number of small steps, each controlled by enzyme catalysts. So instead of a sudden cataract, the burning proceeds as if through multiple locks and canals. Compare the flow of water from Lake Erie to Lake ontario through the Niagara River and the WeIland Canal. We go from the superfast and spontaneous to the slow and controlled. There is beauty in the cataract, but the canal is more useful for navigation.

Yet, what is time? It makes the difference between fast and slow reactions, but “fast and slow” are subjectively viewed in our human frame of reference. In a way, we are “exploding” from conception to death like the Big Bang universe. We could go on indefinitely, being an open system unlike the universe, but nature says “no”, for the sake of posterity and further evolution.

In the same context, reaction rates matter when otherwise very slow reactions are accelerated by enzyme catalysts. Without enzymes, the constituent reaction steps of metabolism would proceed so slowly as to be imperceptible at our time scales. So “the little enzymes that run the world” act both as controls on explosion speeds and accelerators of blocked reactions; they are both brakes and gas pedals.

Between explosion-type speeds and glacier-type speeds life winds its way.