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Think of Energy as Nature's Best Recycling Effort

June 24, 2002|K.C. Cole

If there was ever a pro at poking fun at the know-it-all pretensions of some physicists, it was Caltech's own late Richard Feynman. And more often than not, his ribbing struck some deep shard of truth.

Take his turn on that familiar everyday phenomenon: energy. We buy it, we save it, we waste it; we wolf it down in the form of jelly doughnuts, then desperately try to work it off at the gym; we soak it into our skin as sunlight and scream as it carries the roller coaster over the edge; it stirs breezes and powers stars; it's the quiet potential sitting in a tank of gas and the foamy violence of an ocean wave; it's coiled into springs and frozen into matter. If there is any justice in the world, some Enron executives will go to jail over it.

And yet, as Feynman pointed out, "It is important to realize that in physics today, we have no knowledge of what energy is."

It's even worse than that: We don't even have a sensible way to name it or measure it. "Physicists sometimes feel so superior and smart that other people would like to catch them out once on something," Feynman said. "For those who want proof that physicists are human, the proof is the idiocy of all the different units which they use for measuring energy."

There are calories and joules and ergs and electron volts and BTUs and kilowatt-hours, to name a few--all measuring this nameless thing.

But here's the absolutely amazing thing about energy: The amount of it in the universe is absolutely constant. It never changes. It only alters its form.

Consider the energy you used to get up this morning, open the paper and read this column. It came, of course, from that steak you ate last night. The steak got its energy in turn from the cow, which got it from the grass, which got it from the sun.

And that minor earthquake last week. The energy for that bubbled up from deep inside the Earth where radioactive atoms melt rock, moving continents around. Those atoms in turn got crammed with energy during the gravitational collapse of some long-gone star, later to be spewed into space, eventually condensing into the glob we now call Earth. The gravitational energy that crushed the star, in turn, can be traced back to the big bang, the explosive expansion of the universe.

It's an endless regression of recycling.

And it doesn't stop there.

The universe got the energy to bang, in turn, from the energy of the vacuum of empty space, which, oddly enough, is also packed with energy. This energy of emptiness comes from the perpetual quivering inherent in everything, thanks to the innate properties of quantum mechanics. A large enough quiver, according to some cosmologists, could have begun the whole shebang.

This sobering thought led MIT cosmologist Alan Guth to his now infamous conclusion: The universe is the ultimate free lunch. "Conceivably," Guth said, "everything can be created from nothing."

Of course, the "nothing" that we're talking about here is really a very energetic speck of vacuum. But as far as the universe is concerned, the energy of a vacuum and the energy of a Mars candy bar are substantially the same. Energy is energy. Whatever that may be.

"As far as we know, there are no real units, no little ball bearings," Feynman said. "It is abstract, purely mathematical, that there is a number such that, whenever you calculate it, it does not change. I cannot interpret it any better than that."

Of course, if the amount of energy in the universe never changes, you might well wonder how can there be such a thing as an energy problem. Why the Middle East? Why Enron? Why world hunger, for that matter? Why not, to paraphrase the queen: "Let them eat vacuum?"

The reason is that, while we don't ever use up energy, we do use up useful energy. Before and after the atomic bomb, Hiroshima, Japan, contained--roughly speaking--the same amounts of energy, but one would hardly call them equivalent. A tree spends centuries soaking up the energy of the sun and soil, and releases it all in an hour in a fire. But the ashes aren't good for much. It can take a thousand years to turn muscle and thought into cities, eons to pack sunlight into fossil fuels and millions of years to store energy in stars. Using energy is often quick and easy, but making it useful is long and hard.

Conservation of energy is built into nature, as Feynman pointed out. "But she does not really care; she spends a lot of it in all directions."

To spend it wisely, now that is up to us.

Readers can reach K.C. Cole at

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