Stardate 20020718.1219

(On Screen via long range sensors): William Quick asks for my comments on a report in the BBC that someone has found an exception to the Second Law of Thermodynamics.

When you're talking about esoteric issues, it's really easy to get confused, and sometimes you can tell from the way that a reporter is writing that they are not totally up to speed. For instance, the article states:

The Second Law states that the entropy - or disorder - of a closed system always increases. Put simply, it says that things fall apart, disorder overcomes everything - eventually.

The problem begins here. That isn't what the Second Law states.

To begin with, the Second Law doesn't "state" anything; it's a formula and not a legal principle stated in words. What it implies is that in any transaction in which energy is transformed, some of the energy becomes useless.

But that doesn't result in the BBC's summary. A better statement would be this: in a closed system, entropy cannot decrease. That's not the same. So far as I know, there's no contradiction to the Second Law if the entropy of a closed system stays level, as long as there are no transactions taking place within that system that the Second Law governs.

The other problem with this report is that the experiment as described wasn't actually a "closed system".

Professor Denis Evans and colleagues at the Research School of Chemistry at the Australian National University put 100 tiny beads into a water-filled container. They fired a laser beam at one of the beads, electrically charging the tiny particle and trapping it.

The container holding the beads was then moved from side to side a thousand times a second so that the trapped bead would be dragged first one way and then the other.

The researchers discovered that in such a tiny system, entropy can sometimes decrease rather than increase.

The Second Law may well be the most misunderstood, and most seriously abused, of the major findings of modern physics. It's a favorite of creationists, for example, who use the misstatement "order cannot increase" to try to claim that this makes evolution impossible, for how could larger and more complex creatures evolve from less complex ones?

What they don't notice is that the same argument would also suggest that simple reproduction would also be impossible. You start with two critters and end up with three; three critters represent more order than two critters.

It would also forbid maturation: you start with a baby critter (small) and it grows to an adult critter (big). Order just increased, because there's more ordered mass there.

The reality is that none of those cases violate the Second Law, because these are not closed systems. An open system is one where organized energy can be accessed from outside, and disordered energy can be exported outside. In a closed system, no external ordered energy can be accessed and all disordered energy must be retained.

The Earth's biological system is open. Ordered energy in the form of sunlight is imported to the system, and disordered energy in the form of heat is radiated away into space. So while on a low level individual energy transactions turn ordered energy into disordered energy, we can discard that; it doesn't accumulate here.

Garbage doesn't accumulate in cities, because we haul it away. By the same token, entropy doesn't accumulate on earth because we export it.

Note that for a system to be classified as open it doesn't require both a source of ordered energy and a sink for disordered energy. If either alone are present, the system is not closed.

The system described in this article receives ordered energy in the form of external reciprocating force applied to the container. So it's open, not closed.

What the researchers actually say is that on a fine level they observed certain transactions which were thought to be governed by the Second Law, and for brief intervals they didn't seem to see any accumulation of local disorder. This is hardly a revolution; it's just a refinement. It doesn't mean that THE SECOND LAW IS FALSE!!! and that we can now all happily start working on perpetual motion machines.