Friday, August 17, 2007

BBC Radio: superluminality and two more topics

In this radio segment (Real Audio; Windows Media people should download Real Alternative), they talk about abolishing some kinds of taxes, wars, but also three science topics.

Depression over-diagnosed

Before 17:30, they talk about the opinions of Gordon Parker, an Australian psychologist, who argues that the clinical threshold for depression is too low and people like to go Prozac as soon as it's cloudy outside or as soon as their boss forgets about their birthday.




Well, my experience certainly tells me that he's right. Things are statistically supposed to go down roughly in 50% of each life or so. However, whenever someone is unhappy about anything, people instantly recommend psychologists to each other or visit psychologists themselves - even though the unhappiness has usually nothing to do with psychology.

Parker says that this tendency is a result of clever marketing. In the same issue of the journal, Ian Hickie performs exactly this kind of marketing. Hickie also celebrates that the new approach has "removed the old stigma surrounding mental illness". In other words, the new approach has made the term "mental illness" vacuous. And he's happy about it because even though it's vacuous, his colleagues still benefit from it.

Steve McIntyre

At 17:30, they talk with Stephen McIntyre by phone. In a very polite discussion, they reveal that the changes made because of his observations are not insignificant for the U.S. temperature records. We have already talked about the fact that 1934 became the hottest year in the U.S. history again.

Superluminal signals

Around 20:00, they start to talk to Günter Nimtz and oversell a huge amount of bizarre statements about superluminal signals, violations of special relativity, and time machines that he has constructed or nearly constructed in his lab.

Two years ago or so, Robert Helling explained what these experiments are all about. As far as I can say, there is nothing new about Nimtz's findings or observations and not much interesting about them either. He's been doing the very same things for decades.

He builds a setup in which the maximum of a wave moves faster than light (although you need amplifiers to find where the maximum is at the end). That's of course possible. In fact, it's very easy. You can make such things with normal classical electromagnetic waves as long as you have a layer of material where they exponentially drop. In analogy with Schrödinger's equation, you may realize that tunneling can be very fast.

However, microscopically, no signal or information is moving superluminally and nothing is violated about special relativity whatsoever because all these waves perfectly satisfy Maxwell's equations where the speed of light is safely bounded. Nimtz must know that, I think, so his behavior seems dishonest to me.

There are much easier arrangements that make "something" move faster than light. Take a knife whose blade is almost horizontal but not quite: the angle is "1/N" rads. Move it down with the speed "v". The intersection with the horizontal plane of the table moves by the speed "vN" which can be easily greater than "c" if the angle is very small.

Or shine light on a distant screen and rotate the light source around. The image can easily move faster, too. You can surely construct many other examples. In each case, it is only irrelevant, fictitious, conventional locations such as the maximum, intersection, image that move faster than light. They are not real objects and they can't carry any information with them.

The only new aspect of experiments such as Nimtz's one is that it uses not only insights about geometry from the ancient Greece but also some properties of wave equations realized in the 19th century. The latter are already too complex for most listeners so that they are ready to believe silly statements that his experiments change something about special relativity.

The lady in the BBC asks him whether his finding are robust and reproducible etc. What do you expect that such guys will say? Of course that such a guy will say the best about his work he can. The experiment is reproducible: it is just the interpretation that is completely wrong. In Nimtz's case, it is probably wrong because of his dishonesty, and in the case of those who buy it, it is wrong because of their poor understasnding of basic physics.

And that's the memo.

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