## 20210712

### Cause of the cosmological redshift

PSI Blog 20210712 Cause of the cosmological redshift

This week’s book prize goes once again to Abhishek Chakravartty for another good question:

“In PSI Blog 20210614, you have explained that when neither the medium in which the wave is travelling changes nor the pressure within the medium in which the wave is travelling increases, it is impossible for the velocity of the wave motion to increase although in such cases, it is still possible for the wavelength of the wave to increase due to other reasons. So in such cases, if the wavelength of the wave increases due to other reasons, does it mean that the frequency of the wave decreases? I am asking this question because velocity of wave motion is equal to wavelength multiplied by frequency.”

[GB: The wave velocity is a property of the medium and remains constant as long as the properties of the medium remain constant. The frequency is given at the source and remains constant. Thus, the change from water to air changes light velocity from 225Mm/s to 300Mm/s while the wavelength of light increases by 1/3. The frequency remains the same.

The Imperfect Wave

Once again, because the medium controls velocity and is constant and the source controls frequency and is constant, the only thing left to change is the wavelength: the reason for the cosmological redshift. The relationship you cite: velocity (cm/s) = frequency (cycles/s) X wavelength (cm) is a mathematical idealization that fails to consider entropic changes that must occur over time during wave reproduction. In other words, no two waves can be perfectly identical per the Ninth Assumption of Science, relativism (All things have characteristics that make them similar to all other things as well as characteristics that make them dissimilar to all other things). Here, we are treating a wave as a thing (a microcosm consisting of many particles).

A wave, then, is an agglomeration of submicrocosms colliding with each other in response to some impact that occurred within the medium they compose. To produce a second wave form exactly like the first, those submicrocosms must collide in exactly the same way as they did in the preceding wave. This is impossible, of course—there are no identities in the Infinite Universe. Thus, all waves are subject to “entropic changes” as mentioned above. Once formed by a disturbance at the source, the constituents of each wave are subject to divergence per the Second Law of Thermodynamics. It takes time for each of those interparticle collisions to occur. That lag appears as an increase in wavelength—a “redshift” if you will.

Unlike the usual “redshift” produced by the doppler effect, this “entropic redshift” is not a result of measurement due to source or observer motion. It is simply a function of distance. With light, the effect is miniscule and only can be observed after light has traveled cosmological distances. Remember that what is generally considered the “cosmological redshift” also includes the doppler effect due to the divergence and convergence of cosmological bodies. For nearby galaxies, such as Andromeda, the motion toward us easily overwhelms the entropic redshift, resulting in the well-known blueshift of Andromeda.

I am not too sure with regard to your last question about the possibility that an entropic redshift could result in a decrease in frequency. You are correct that the equation v=fλ (where v=velocity, f=frequency, λ=wavelength) normally describes the situation. Therefore, we would expect entropic redshifts to result in decreases in frequency. But frequency is produced at the source and normally remains unchanged. As an example, I could paddle my boat at one paddle per second. Once the wave produced by each paddle is underway, nothing will change that 1 cycle/s frequency. The waves will diminish and disappear, but they will never have an increase in frequency. Whether they could have a decrease in frequency is problematic. I suppose that an entropic increase in wavelength could be accompanied by an entropic decrease in frequency, thus satisfying the above equation.] 