twin universe cosmology

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Cosmology of twin universes (p 10)

  1. Red shift and the Robertson-Walker metric with a variable speed of light.

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The derivation of the distance from the red shift z, with "variable constants", has already been presented. See reference [13], sections 3 to 7. The index 1 refers to the emitter and the index 2 to the receiver. For example, c₂ is the current value of the speed of light, as measured in the observatory. It is assumed that the Rydberg constant (ionization energy of hydrogen) follows (94)

Then we obtain:

(95)

Equation 95

The value

g

= 1 is chosen in order to obtain the classical value.

Expanding the function 1/R(t) into a series with respect to

(96)

we obtain:

(97)

Equation 97

This is nothing but Hubble's red shift law, which still holds in this variable speed of light framework. From measurements of d₂, c₂ and z, we can derive the so-called Hubble constant, i.e. the age of the Universe.

(98)

identical to the standard value. Then the distance to the object d₂ is evaluated:

(99)

Equation 99

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When z tends to infinity, we obtain the cosmological horizon 3/2 c₂ t₂, which is twice smaller than the standard value 3 c₂ t₂. If we compare the current model to the EdS model, we get, for the distances, the ratio:

(100)

Equation 100

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They are similar for small z values, as shown in the following figure. For small z values, the distances, as derived from the current model, are slightly larger.

h

is close to unity for z = 1.5. Then

h

tends to 0.5 when z tends to infinity. For z < 2.5, the difference between the two distance evaluations is less than 5%.

Figure 20: The distances for the current model and for the Einstein-de Sitter model, and the ratio

h

of these distances, as a function of the red shift.

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In reference [14], section 3, the evolution of the angular size of a distant object as a function of z was calculated. For the EdS model and constant size objects, the law is:

(101)

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This function of z has a minimum for z = 1.25, and then f tends to increase linearly with z. Figure 21 explains why it leads to an overestimation of f for large z values.

Figure 21: Why the classical model overestimates the angular size of objects with large red shift. The measurement, at the time of reception, corresponds to a "fossil" angular size, when the object was closer.

In the current model, the situation is fundamentally different, as objects are assumed to expand with the Universe. See figure 22.

Figure 22: Current model: light propagates along geodesics. The angular size remains unchanged.

The corresponding formula is:

(102)

Equation 102

When z tends to infinity,

f

tends to a constant value.

Note that in our model:

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In reference [14], this was used to compare the current model to the EdS model, applying to radio-QSO data (Barthel and Miley, 1988 [35]), giving a slight advantage to the first. Obviously, a single test, involving many assumptions about the nature of the observed objects, could not validate the model. See the discussion in reference [14].