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Q & A: light and the Planck scale

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Most recent answer: 06/14/2015
Why don't we see measurable differences in the speed of light due to variances of the flatness of space at Planck length scale?
- Neil Richins (age 48)
Dublin Ireland

We don't really know what's happening on the Planck scale, except that it happens very fast, compared to the period of visible light, and that within a volume of a cubic wavelength of light, it's happening in different ways at zillions of different spots. So the light just sees a well-averaged medium Perhaps the light behavior that we see already shows effects of those small-scale variances. We'd still just see an average behavior.

Here's a bit of an analogy. Liquid water has all sorts of fluctuations going on at the scale of molecules and picoseconds. Still, light travels through it without a whole lot of scattering. Any Planck-scale fluctuations in spacetime are much faster and smaller-scale so averaging should smooth them out far better than it smooths out the proeprties of liquid water.

Mike W.

(published on 06/14/2015)

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