- #26

DaveC426913

Gold Member

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It's not difficult at all. This is the real world; physics is not paralyzed just because mathematical definitions don't fit well.Dave, is it not difficult to maintain scientific veracity without mathematical rigour?

Remember the context here:

For a photon to have zero frequency, it would need to have a wavelength infinitely long. But a photon whose wavelength is longer than the diameter of the universe is

*effectively*infinite. To-wit: being

*100 billion ly long*and being

*infinitely*long makes no change in it the property of its frequency; it's still undefined.

So: a wavelength greater than the diameter of the universe is "as close to being infinity as is meaningful".