Worth a thought

[Klover]

David Bodanis, author and academic
From the Guardian


Imagine if a God had created the universe and he had said: "I'm going to insert a fixed amount of energy into this universe of mine. I will let stars form and explode, and planets move in their orbits, and I will have people create great cities, and there will be battles that destroy those cities, and then I'll let the survivors create new civilizations. There will be fires and horses and oxen pulling carts; there will be coal and steam engines and factories and even mighty locomotives and iPhones.

"Yet throughout the whole sequence, even though the types of energy that people see will change, even though sometimes the energy will appear as the heat of human or animal muscle, and sometimes it will appear as the gushing of waterfalls or the explosions of volcanoes; despite all those variations, the total amount of energy will remain the same. The amount I create at the beginning will not change. There will not be one millionth part less than what was there at the start."

Expressed like this, it sounds the sheerest mumbo jumbo, like something Yoda would mysteriously speak in Star Wars; or like the popular superstitions that would drive Richard Dawkins into an apoplexy.

What's extraordinary, though, is that it's true (although the God part is contestable).

When you swing closed a cupboard door, even if it's in the stillness of your home at night, energy will appear in the gliding movement of the door, but exactly that much energy is removed from your muscles. When the cupboard door finally closes, the energy of its movement won't disappear, but will simply be relocated to the shuddering bump of the door against the cupboard, and to the heat produced by the grinding friction of the hinge. If you had to dig your feet slightly against the floor to keep from slipping when closing the door, the earth will shift in its orbit and rebound upward by exactly the amount needed to balance that.

This was only first fully recognized in the Victorian era of the industrial revolution, when steam engines showed it happening all the time. Measure the chemical energy in a big stack of unburned coal, then ignite it in a train's boiler and measure the energy of the roaring fire and the racing locomotive. Energy has clearly changed its forms; the systems look very different, but the total is precisely the same.

Later in the Victorian era, when Darwin had proven that God wasn't needed to create the living species on our planet, this vision of an unchanging total energy was often felt to be a satisfactory alternative, a proof that the hand of God really had touched our world.

Since then, researchers have found that it's not quite as absolute as at first believed. Stars and a few other objects can be places where fresh energy gushes forth into our universe (though in such cases, a balancing amount of mass usually disappears). Down on earth though, we're reduced to simply trying to stir it around.

Which has not been without its consequences. For millennia, humans had been limited in what they could do by the power of the sugars in their muscles, or the similarly stored sugars in working animals. Simple wind and water power helped a bit; by the time Durham Cathedral was built, waterwheels could sometimes match the output of 60 or 70 men. But only when much denser forms of energy were accessed could more complex civilizations really get started.

Or rather, civilizations sometimes were complex before, but they depended on hundreds of thousands or millions of peasants working as near-slaves to create enough excess for a small number of scribes, priests, warriors, and bronze age Paris Hiltons to live in even moderate ease. To have a large democracy at a comfort level we would appreciate, something more than freshly created muscle sugars had to be used for fuel.

The first solution was to hunt for more concentrated sources of these sugars. Trees are good, since they accumulate modified sugars over many years, storing that chemical energy in the wood of their trunks, and never erupting with proto-Marxist grievances when dragged away to be exploited. Charcoal is even better, for it's denser and easier to transport (and burns more cleanly).

Yet even aside from the problem that forests are easily cut to oblivion - as much of England's was by late medieval times - there's a more ingenious place to hunt. A tree holds stored energy that was built up from a few decades, or at most a few centuries, of incoming sunlight. But coal or oil? Those come from several hundred million years of stored sunlight, locked away in deceased forests or microbes. It's a very, very large bank to draw from. The British empire didn't just draw from the labour of several continents. It used the accumulated energy from those past millions of years of fossil fuels, too. Once mines and wells were in place, a tremendous amount of work could be done with a minimum amount of bicep flexing, using this ancient solar energy, transformed once more.

But not all fuels are created equal. A powerful pattern began to emerge, for certain fuels are far denser in energy than others. Toss a scrap of paper on a stove's lit flame, and it'll just singe or burn slowly; toss a thimbleful of petrol, and it explodes. The key factor is the ratio of hydrogen to carbon in a fuel.

The main fuels used in history form a nearly exact sequence, from ones having less hydrogen to ones having more. Wood and charcoal were the earliest fuels, and have only a little hydrogen. Much of their burning is wasted in pouring out great gusts of carbon, which was needed to build up the tree from which the wood came, but doesn't do much for the user burning that wood.

Coal has more hydrogen, and its burning can be cleaner. Oil - which dominated next - has yet more hydrogen per unit of carbon; natural gas has even more, and its burning is the cleanest and most efficient of them all. The trend line points pretty strongly to a pure hydrogen economy - but when that will occur is in the hands not of the scientists, but our wise political masters.

[LustBunny]

wow thats entirely too long for 2 am

[pico]

Hes not doing anything but stating what is really everyday knowledge. It's like saying 'there is oxygen in our atmosphere' - there's really no point in making the statement.

Back to the article though - there might be the same amount of energy on earth, but mankinds' potential to more effectively harness that energy needs to be pointed out as well.

Back in the 60's, gasoline was gasoline. We didnt really grasp the potency of 91 octane vs whatever else, now-a-days you have engines specifically tuned to whatever grade of gas to get the max performance from that specific fuel.

Nuclear energy - take a hot metal cylinder and boil water for years. Thats a big step from a piece of wood the same size burning and boiling water.