Reality is Fuzzy…Fortunately

I’ve sometimes found it ironic that many of us strive for clarity and precision in our thinking when the world, as best we can tell, is fundamentally fuzzy. In fact, one can argue that the world, at least as we know it, could not exist except for the fuzzyness at its roots. I’m thinking here, of course, of the discoveries embodied in quantum mechanics (if you’re interested, search for the ultraviolet catastrophe and standing waves).

Yesterday I learned about another example of the importance of fuzziness. One that is pretty central to life on Earth.

Most people know that the sun shines as a result of nuclear fusion converting mass into energy, mostly involving turning four hydrogen nuclei, aka protons, into one helium nucleus. But what I didn’t know until yesterday was that the sun isn’t hot enough for that to happen except for the intervention of fuzziness. To enable the reaction to run “normally” the sun would have to be much more massive. At its actual mass it would barely shine, and then not for long. Which would not be good for life on Earth.

The fuzziness in this case is a bizarre sounding quantum mechanical effect called tunneling. What it boils down to is this: sometimes, even though two protons might not be moving fast enough (i.e., be hot enough) to overcome their mutual electrostatic repulsion to collide and stick together, they do it anyway. It’s as if a ball not thrown hard enough to pass over the top of a wall sometimes made it anyway.

This isn’t because energy mysteriously appears and then vanishes, although that is allowed under quantum mechanics, too. It’s just the result of reality not “allowing” too much “precision”. There’s always a non-zero probability the protons or the ball will make it. For large objects the probability is so small you’ll never observe it happening. For very small objects like protons the probability is significant.

So the next time you find yourself complaining about a lack of clarity or precision remember this: good and important things can come from fuzziness.

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