7 The V-effect - Redshift by gravitation.

The thought, that gravitation, or any other effect, can give a redshift, is often scornfully called "tired light" or a "decay" of the photons.

We can often read in astronomical literature, that "it has been proven, that light cannot change frequency by gravitation, when it passes through a static gravitational field". "This can be shown with calculation, using the laws of curved space-time."

Comment:
No laws of curved space-time are needed to prove this for static gravitational fields. It is obvious that neither particles nor photons lose energy by passing through a static gravitational field. But they lose energy by passing through gravitational fields.

The explanation is, that there is an interaction between the particle and the other matter in the field. The field is no longer static. This is valid both for particles and for photons, as will be shown later.

In most books on astronomy we find a comment like "It has been proven by Ya. B. Zel`dovich, that gravitation or "tired light" cannot explain the Redshift".

7.1 Statement by Zel`dovich.

In Zel`dovich (1963) he gives three reasons why it is impossible. ( A good summary is given in Gravitation (1974), page 775, and I refer to that text ) :

(1) "If the energy loss is caused by an interaction with the intergalactic matter, it is accompanied by a transfer of momentum; that is, there is a change of the direction of motion of the photon. There would then be a smearing out of images; a distant star would be seen as a disc, not a point, and that is not what is observed."

Comment:
The transfer of momentum does not necessarily give any "smearing out of images".
a) Change of momentum in the direction of the movement does not have this effect.
b) If all photons pass the same way, they all change momentum in the same way and change direction in the same way. So also change of momentum sideways does not have any smearing out effect. ( An example is the light from a star, passing the sun. It bends off, but is not smeared out. )

So, Zel`dovichīs first argument must be false, as I see it !

So let us look at the second !

(2) "Let us suppose that the photon decays, giving up a small part of its energy to some particle. It follows from the conservation laws, that the particle must move in the direction of the photon, and must have zero rest mass. Because of the statistical nature of the process, however, some photons would lose more energy than others, and there would be a spectral broadening of the lines, which is also not observed."

Comment:
Evidently Zel`dovich looks at the process only as a quantum effect. But if it is an effect of gravitation, there is no need to look at it in this way. The ray of light, passing close to the sun, is influenced by gravitation, so that it changes its momentum, and still there is no broadening of the lines.

So, also Zel`dovichīs second argument must be false !

So let us look at the third !

(3) "If there does exist any such decay process, then simple arguments of special relativity", that Zel`dovich attributes to M P Bronshtein, and spells out in detail, gives this comment by Zel`dovich : "Thus, if the decay of photons is possible at all, those in radio waves must decay especially rapidly ! This would mean that the Maxwell equation for a static electric field would have to be changed... There is no experimental indication of such effects... Thus suggestions that there is an explanation of the redshift other than Friedmannīs fail completely."

Comment:
Obviously Zel`dovich also here does not think of the influence on the photons as anything else than a "decay" in a quantum way. But the photon can change momentum in other ways. It is accepted that photons change direction and thus momentum by gravitation. It is also accepted, that strong gravitational fields, e.g. near neutron stars or black holes, can give a gravitational redshift - the photons lose energy or momentum, when they leave the heavy object. A third is "Einsteinīs gravitational lenses". And in all these cases there is no difference for different frequencies.

So, also Zel`dovichīs third argument must be false !

Another way of proving the impossibility of gravitational redshift is, as is often done, to quote another well-known astronomer, who has said, that "it would call for a new physiological law".

Do we have to look for a new physiological law, to get an alternative explanation of the redshift, or can the photon lose energy by ordinary gravitation ?
Yes, it can ! As I said earlier, photons leaving a heavy object, as a neutron star, lose energy by the gravitation and get a redshift.

But photons travelling through the Universe, without coming close to any strong gravitational field, how could they be "held back" by gravitation ? Let's look at it

7.2 Calculation : One particle passing another particle.

We start looking at ordinary particles as in 2.2. First one particle passing another particle. In this case the particle, B, is not as heavy as the object in 2.2, so also the particle B starts moving.

7.3 Calculation : One particle passing two particles - The V-effect.

It is easier to calculate with two symmetrical particles, than with one, as in 7.2.
( As compared to earlier calculations Y is changed. We also leave the influence between the two B - particles. That is a general gravitation problem. )

Only the steps in the calculation are shown here.