29 September

For so long it seemed logical that big things are complicated, and small things are simple. In living things, organisations, politics - wherever. Bacteria have now taught us we had this completely backwards, the smaller you go with living things, the more complex things become. But it's not just complexity, it's also energy, we think big things are more powerful. But have a look at these energy densities of different fuels - energy density is roughly the amount of energy you can get from a given mass or volume of a material. Not an argument for nuclear energy by the way, it has all sorts of problems, but you can see that as you go smaller, the energy available goes off the scale. (These numbers have units of MJ/kg - means how many million joules of energy is available per kilogram of the material.) Wood - 16.2 Ethanol - 26 Coal - 30 Fat - 37 Petrol - 46 Natural gas - 55 Plutonium - 2,239,000 Thorium - 79,420,000 Uranium - 80,620,000