April 28, 2016

WE ARE ALL DESIGNIST NOW:

The Fine-Tuning of Nature's Laws (Luke A. Barnes, New Atlantis)


Today, our deepest understanding of the laws of nature is summarized in a set of equations. Using these equations, we can make very precise calculations of the most elementary physical phenomena, calculations that are confirmed by experimental evidence. But to make these predictions, we have to plug in some numbers that cannot themselves be calculated but are derived from measurements of some of the most basic features of the physical universe. These numbers specify such crucial quantities as the masses of fundamental particles and the strengths of their mutual interactions. After extensive experiments under all manner of conditions, physicists have found that these numbers appear not to change in different times and places, so they are called the fundamental constants of nature.

These constants represent the edge of our knowledge. Richard Feynman called one of them -- the fine-structure constant, which characterizes the amount of electromagnetic force between charged elementary particles like electrons -- "one of the greatest damn mysteries of physics: a magic number that comes to us with no understanding by man." An innovative, elegant physical theory that actually predicts the values of these constants would be among the greatest achievements of twenty-first-century physics.

Many have tried and failed. The fine-structure constant, for example, is approximately equal to 1/137, a number that has inspired a lot of worthless numerology, even from some otherwise serious scientists. Most physicists have received unsolicited e-mails and manuscripts from over-excited hobbyists that proclaim, often in ALL CAPS and using high-school algebra, to have unlocked the mysteries of the universe by explaining the constants of nature.

Since physicists have not discovered a deep underlying reason for why these constants are what they are, we might well ask the seemingly simple question: What if they were different? What would happen in a hypothetical universe in which the fundamental constants of nature had other values?

There is nothing mathematically wrong with these hypothetical universes. But there is one thing that they almost always lack -- life. Or, indeed, anything remotely resembling life. Or even the complexity upon which life relies to store information, gather nutrients, and reproduce. A universe that has just small tweaks in the fundamental constants might not have any of the chemical bonds that give us molecules, so say farewell to DNA, and also to rocks, water, and planets. Other tweaks could make the formation of stars or even atoms impossible. And with some values for the physical constants, the universe would have flickered out of existence in a fraction of a second. That the constants are all arranged in what is, mathematically speaking, the very improbable combination that makes our grand, complex, life-bearing universe possible is what physicists mean when they talk about the "fine-tuning" of the universe for life.

Posted by at April 28, 2016 5:08 PM

  

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