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Pam Donegan



A science writer dares to disturb the universe.

MY DESK HAS FALLEN VICTIM to the second law of thermodynamics again. Just the other day, the top was neat and orderly: unpaid bills piled at one end, pencils and pens sitting smartly in their pewter mug, my two staplers lined up like racehorses at the starting gate, and a nice two-foot-square clear spot in the middle for doing work. Now the bills have slumped into the center, the staplers are grazing in separate pastures, and the writing implements lie all over my strewn papers like candy sprinkles on a cupcake.

"What's going on here?" I grumble as I ponder the daunting task of extracting the phone bill from this avalanche without the aid of a St. Bernard.

Science gives the answer to my disgruntled question. My desk, according to physicists, is obeying a natural law, which predicts that everything will become more spread out and disorganized over time. (The other possibility, of course, is that I'm just an untidy person -- but I think I'm just going to have to side with the physicists on this one).

Assuming, then, that paperwork and pens respond to a higher authority, what does this say about the fate of the cosmos? If you answered: "We're going to have a hard time paying the phone bill," you're right. But there's more to it than that.

The universe operates by certain ground rules. The most important of these are the laws of thermodynamics, which specify how energy should comport itself. There are two main laws. The first says that energy can be neither created nor destroyed. The second states, in the poetic words of German physicist Rudolf Clausius, who wrote it down in 1850: Die Entropie das Welt strebt einem maximum zu. Translated, it says that "entropy," the mixing and spreading of matter and energy, tends towards maximum. More colloquially, it says the universe is going to somewhere-not-very-pleasant in a hand-basket. But more about that later. Right now, let's fill in some details about the first law.

When physicists say that energy is always conserved, they are assuming that the universe is a closed system. Nothing goes out the door, and nothing comes in through the transom -- energy is simply recycled. Imagine working out on your Stair Master in a windowless room. Just before you passed out, you would discover that your energy hadn't disappeared, it had just changed from one form to another. Your body would have converted potential energy (donuts and French fries) into kinetic energy (the pumping of your legs) and thermal energy (the heat radiating from your flushed face and dripping sweat).

Everyone loves the first law of thermodynamics. The world seems a happier place once you know that, no matter how hard you try, you cannot destroy energy. When I first heard of this principle in grade school, I became fascinated with energy conversions. I dragged out my brother's old Hot Wheels set, pieced together the segments of flexible orange roadway, and watched the gravity-given potential energy of the elevated starting ramp change to the kinetic energy of the tiny cars speeding down the track. The higher the ramp, the farther they traveled. I devoted a great deal of time to this rigorous scientific study. Eventually I came to realize that the lime-green Camaro and the bronze '34 Chevy were definitely the neatest cars.

Although my experiments were meticulous, at first I didn't see where the "thermo" entered into toy car dynamics. But then it occurred to me that they weren't called "Hot Wheels" for nothing. These two-inch-long speedsters generate heat as they zip along the plastic roadway. The heat comes from friction -- the rubbing together of uneven surfaces. A Hot Wheels track may be slick to the touch, but under a high-powered microscope, the surface appears as a jumble of fibrous speed-bumps, pinpoint potholes, and bacterial road-kill. Other microscopic nooks and crannies adorn the smooth plastic wheels and polished ball bearings. With all that surface crustiness, no wonder even the speedy lime-green Camaro finally ground to a halt.

It was also during the Hot Wheels experiments that I became aware of the real-world disappointments of the first law of thermodynamics. Energy is ultimately conserved, but it is not always conserved the way you'd like it to be. I found that no matter how high the ramp, or how carefully I arranged the curves and straightaways, my miniature racers never made it much beyond the second loop-de-loop. They usually fell off with a disappointing clatter halfway up. Their "hot wheels" were draining power from the potential to kinetic-energy conversion, and nothing I could do would bring them anywhere close to perpetual motion. Even if engineers at Mattell(TM) could design a frictionless car and track -- an impossible task, let me assure you -- the air, full of billions of swirling molecules of nitrogen, oxygen, argon and water, would provide the friction to stop the cars.

Philosophically, I was comforted knowing that the Hot Wheels energy didn't disappear -- it just wafted around in my basement as a faint warmth -- but my "experiments" would've been a lot more fun if the energy had stayed kinetic instead of thermal. Besides, the heat energy wasn't doing anybody any good. I couldn't put it back in the cars, and the basement was still pretty cold.

This unsavory energetic trend is what the second law of thermodynamics is all about. It states that every energy conversion, no matter how small, pays a toll in heat. Most of this heat cannot be converted back to another kind of energy. It just spreads out to the ends of the universe like drops of milk in a coffee mug.

The second law further states that this energy dispersal cannot be reversed. The universe works in one direction only: from potential energy to heat; from order to disorder. Theorists euphemistically call this one-way phenomenon "time's arrow"; but the sad truth is that, eventually, heat will scatter completely, and the universe will reach a state of maximum entropy. Like the paperwork on my desk, everything will be an indecipherable jumble. And, also like my desk, no one will be able to get any work done.

Fortunately, for those of us who thrive on order, the relentless river of universal disorganization contains a few eddies. Life on Earth is the most obvious example. Somehow, on our planet the original primordial gumbo sat up and arranged itself into the layered lasagna of life. Now every bacterium and blue whale violates the spirit of the second law because it represents the creation of order from disorder.

This order is possible because the Earth is not a closed system. The heat energy of the sun drives life's processes. Plants take solar energy and convert it into the potential energy of their edible tissues via photosynthesis. Blue whales, 90 feet long and 150 tons, exist only because they gulp tiny shrimp that munch plankton that eat algae that sit in the sun photosynthesizing all day. We think we're getting something from nothing, but it just isn't so. When the sun finally runs down, our planet's oasis of order will have nothing to power it, and the solar system will spread its small energy reserves into the cosmic coffee au lait.

But, according to astrophysicists, this death by disorganization is at least five billion years away, so there's little need to lose sleep over it. Meanwhile, I'm daring to do my part to stamp out entropy -- I'm straightening up my desk.