21 April 2006

Trouble with Goldilocks

What if the universal constants, the numbers that are supposed to be so well tuned that life wouldn't exist if any of them were just a fraction of a percent different -- weren't actually constant?

It is almost incontrovertible that one of the most puzzling aspects of reality is the apparent fine-tuning of the universe for life. If several key absolutes, like the strength of electromagnetism and the mass of the proton, to name but two, were just a tiny fraction of a percent different than what they are, life wouldn't exist -- atoms would fly apart, stars would never ignite, and so forth.

Or so goes the "anthropic principle" as cosmologists and other scientists who spend their days thinking about these things call it. A more prosaic description employes the Goldlilocks scenario: this universe is just right for life.

Theists, including some adherents of intelligent design, claim this seeming perfection means the universe isn't the product of any old random quantum variations, but must have been designed to play host to life. It's hard to take issue with the fact that the universe does indeed seem too good to be true. Science fiction author Robert J. Sawyer even used it as a central plot device in his novel Calculating God. All those coincidences have added up to make a conclusive case for a supreme being, said the alien to the human.

There are ways around this argument. The most commonly cited by cosmologists is the possibility that our universe is only one of an infinite number of universes, each with different values for the constants that determine its nature. It is therefore inevitable that one of those universes would be hospitable to life. Or, instead of an infinite number of universes existing simultaneously, maybe universes have been created and destroyed in an eternal cycle; sooner or later, one of those universes will be hospital to life. That would be ours.

Others point out that this is a really circular reasoning. Douglas "Hitchhikers Guide the Galaxy" Adams' story of the self-aware puddle illustrates this point of view succinctly:
Imagine a puddle waking up one morning and thinking, "This is an interesting world I find myself in, an interesting hole I find myself in. It fits me rather neatly, doesn't it? In fact it fits me staggeringly well. It must have been made to have me in it!"
There's also the somewhat arrogant assumption behind the anthropic argument that life is impossible except under the conditions with which we're familiar.

So far, all of these debates hang on philosophical musings, not science. But what if those mysteriously perfect constants, which are commonly represented as mathematical ratios, aren't really constant? Hints that this might be the case are starting to pop up more and more often. And if the constants aren't constant, then what does that say about the whole argument in favor of a designed universe?

The current issue of Science contains a brief news item relevant to this neverending debate:
New measurements suggest that the ratio of the proton's mass to the electron's mass has increased by 0.002% over 12 billion years, a team of astronomers and physicists reports. If so, the ratio and other fundamental "constants" of nature may not be constant after all. "If this small variation exists, it's a revolution in science," says Victor Flambaum, a theoretical physicist at the University of New South Wales in Sydney, Australia, and a member of a different team that 7 years ago reported that another constant may have changed.
The bottom line is we're not yet approaching certainty on such matters. The latest speculation comes from the combined efforts of two groups of scientists, one of which performed some clever analysis of very old light from quasars (poorly understood but very bright objects at the edge of the known universe) while the others shone light through hydrogen right at home in their own lab. Turns out that the spectrum produced is determined in part by the ratio between the proton and electron masses.
The measurement is at the edge of statistical significance. "We have an indication," [physicist Wim] Ubachs says. "I wouldn't call it proof.
Other researchers think they have evidence that the "fine-structure constant" -- another of those all-too-convenient numbers, which determines the strength of the electromagnetic force -- has changed by about six parts per million since the universe was created, although attempts to reproduce those findings have failed.

None of this will get us any closer to explaining the creation of the universe, which is pretty much beyond the scope of science, anyway. But doubts about the alleged "constants" should give us pause when it comes to reaching conclusions about how much tinkering was necessary for life to have arisen. If the constants aren't constant, then how dependent is life on those constants?

I think the ultimate question about life, the universe and everything has a little life left in it yet.

1 Comments:

Blogger island said...

I think that appealing to tired light theories and changing constants in order to shoot down the anthropic principle just because you don't like some interpretations that abuse the science... is about as lame as it gets, but I do like the scenery here... ;)

FYI: You're utterly clueless if you think that Douglass Adams Puddle example comes anywhere close to representing the physics for the anthropic principle.

The puddle example is only given by counter-ideologically motivated people to groups of like-minded individuals as a rebuttal to creationists that are pushing the anthropic principle as evidence for god.

It has little if anything to do with the physics of the anthropic principle.

For example, does the analogy fairly represent the diametrically opposing runaway nature of all of the vast array of the the anthropic coincidences?

Because if it isn't "fairly" represented, then it necessarily harbors unfair prejudice against science.

I don't make the rules... nor do I tell people whom to associate themselves with, but that doesn't mean that the lame rationale of fanatics doesn't make a statement about people that get their information from them.

Let the willful denial begin...

7:05 PM  

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