Monday, 22 December 2003

Breaking the Law

Someone only a few kilometres away from me, at the Australian National University, has been breaking the law. Not content with Squeezing Light and teleporting it, they're now flagrantly violating the Second Law of Thermodynamics.

The 2nd Law, that in a closed system things get messier over time, has long been known to be a true as a statistical approximation. It was also thought to be less true when dealing with short periods of time and small scales. For example, it´s possible that all the air molecules in the room you're in will suddenly, and by chance, all congregate in a corner of it, leaving you gasping in vacuum. But although possible, if you ran a trillion universes each for a trillion times the period since the Big Bang, odds are that that state of affairs wouldn´t occur in even one of them.

The odds of Michael Moore looking like Twiggy tomorrow are considerably greater.

What the ANU team have done was to make an experiment that gave some insight into just how small things have to be, and over what time periods, effects similar to eggs unscrambling, or things falling up happen.
[The] Second Law of Thermodynamics says that the disorder of the Universe can only increase in time, but the equations of classical and quantum mechanics, the laws that govern the behaviour of the very small, are time reversible.

A few years ago, a tentative theoretical solution to this paradox was proposed - the so-called Fluctuation Theorem - stating that the chances of the Second Law being violated increases as the system in question gets smaller.

This means that at human scales, the Second Law dominates and machines only ever run in one direction. However, when working at molecular scales and over extremely short periods of time, things can take place in either direction.

Now, scientists have demonstrated that principle experimentally.
The research also has practical application is the near-future:
The scientists say their finding could be important for the emerging science of nanotechnology. Researchers envisage a time when tiny machines no more than a few billionths of a metre across surge though our bodies to deliver drugs and destroy disease-causing pathogens.

This research means that on the very small scales of space and time such machines may not work the way we expect them to.

Essentially, the smaller a machine is, the greater the chance that it will run backwards. It could be extremely difficult to control.

The researchers said: "This result has profound consequences for any chemical or physical process that occurs over short times and in small regions."
From the looks of it, many biological processes could be subject to such small-scale time-reversal effects, though for such short periods that it´s "lost in the noise". Nanotech - a subject of great importance which I´ve been meaning to post on for a while now - may be different. Nanothech may be harder than we think. Stay Tuned, because if you´re in the 20-to-60 age band, your life (or at least your longevity) may depend on it. The Jehovah´s Witnesses are probably right in this regard, just not for the reasons they think.

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