Saturday, July 15, 2006

Inconstant Constants

A science is any discipline in which the fool of this generation can go beyond the point reached by the genius of the last generation. ~Max Gluckman

Sometimes an article is so bad, it's humorous. Space.com, which is normally a good place for astronomy and space information, put out this gem with its sobering headline, “Scientists Question Nature's Fundamental Laws”, following that with this killer opening line: “Public confidence in the 'constants' of nature may be at an all time low.”

Right.

Just the other day, I saw a Nielson survey showing that people had really come to doubt the validity of Planck's Constant. And I hear that Avogadro's Number is in serious trouble. The “public” doesn't know a scientific constant from a batting average. If someone announced that the value for the speed of light was once 6, the great masses of the world would say, “So?” Unfortunately, many would also say, “What is it now?”

What the story actually talks about, after its melodramatic start, is that some scientists are debating the constancy of constants. That is to say, at some point in the past, the force of gravity may have been greater, the speed of light slower, and so on. This violates one of Einstein's principles, the equivalence principle, which holds that if you perform measurements on nuclear or electromagnetic forces, they should be the same, regardless of where or when the experiment or measurement is performed.

Now we are talking about variations in the “few parts per million” area here. The values involve taking measurements of details of quasars which are a long way off. Another “varying” constant involves the ratio of the weight of a proton to an electron. Moreover, we're talking about such small variations taking place over millions of years.

Then we come to the punchline of the story, because this variation could be due to the change in size of additional folded-up dimensions. And – here it comes – this is a prediction of string theory, which in this story is described as “a popular alternative to relativity.” So the theory that has never predicted anything is now making a prediction.

I am highly skeptical of this whole approach. It has become more common of late to use “variable constants” when a proposed theory doesn't work. It used to be that when a constant didn't fit what you observed, you reworked the theory. Evidently, now the scientist says, “Well, the fine constant was different back then.”

The story says that these radical new views could force the rewriting of the laws of physics. They miss the point. If this approach is true, there are no laws of physics. If the speed of light has varied, how can you state with any confidence how far away a quasar is? If nuclear forces are variable over time, how can you make any predictions about the life of stars? If it's all a big approximation, how do we know anything at all?

It strikes me that the lengths to which some people are going to prop up string theory are getting to be frightening. In a previous article, I mentioned the concern some people have that so much effort has been placed in string theory with so little result. The price for this has been to ignore other avenues of thought. Scientists don't like to admit they've been barking up the wrong tree. Lord Kelvin famously held out against the proposed ancient age for the Earth because his view of the Sun's energy-producing process was still mired in his old theories, which meant the Sun would have gone cold long ago if the Earth were really billions of years old.

Just as one can get blinkered by old theory, one can be blinded by a shiny new one. String theory is twenty years old. Now the scientists who did their thesis work in the subject are finding themselves in a position where they may have barked up the wrong tree. It appears that they are coming up with nearly desperate ideas to validate their work.
String theory looks like the Ptolomeic version of the heavens that held sway for hundreds of years. The convoluted scheme of epicycles did a remarkably good job of prediction within the limits of science. But, over time, cracks appeared in the framework. Rather than patch the old theory by saying that the planets must have slowed down or sped up, scientists began the long process of revamping their ideas.

It's time to stop tying all these strings into cat's cradles and move on. Either scrap the mess or fix it, because it is surely broken. It still may be that string theory has at its heart some fundamental truths, but as long as all it does is describe what was already predicted by other theories, it isn't doing anyone any good. If varying constants is going to be considered a prediction, then string theory had better explain how and why they vary. To do that, researchers are going to have to settle on how many dimensions there are, and they're going to have to start finding direct evidence of them. If they don't, all we'll be left with is a nihilistic view of the universe that leaves no place for any sort of order or logic.

It's time to cut the string.

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