A Possible Solution to the Disagreement about the Hubble Constant

Abstract

The current disagreement about the Hubble constant H 0 was described as a "Crisis in Cosmology", at the April (2018) Meeting of the American Physical Society, and hence its resolution is of utmost importance. This work proposes that the solution to the disagreement between the Planck Collaboration cosmic microwave background (CMB) value of H 0 , together with the very close BOSS Collaboration baryon acoustic oscillation (BAO) value, and the significantly higher value of H 0 found by the SHOES Collaboration cosmic distance ladder (CDL) work, is due to the fact that the CMB and BAO values of H 0 are not for an accelerating universe, as generally believed, but are actually the values for a decelerating universe. In contrast, the CDL value of H 0 is indeed that for an accelerating universe. It is shown that by replacing the negative deceleration parameter in the expression for logH 0 in the CDL work by a positive deceleration parameter, the value of H 0 can be brought down to agree with the CMB and BAO lower values. There is a brief review of the author's decelerating model based on the Einstein de Sitter universe, augmented by a model of dark energy that does not have a negative pressure, but instead has a non-dispersive index of refraction n, causing the speed of light through the dark energy of intergalactic space to be reduced to c/n. As reported earlier, this assumption is sufficient to accommodate the increase in apparent magnitude of the Type Ia supernovae (SNe Ia). Additional support for the model is presented, together with a proposal for astronomical falsification.

A Possible Solution to the Disagreement about the Hubble Constant II

“…Consequently, if an alternative model based on a decelerating universe can get the same distances, to within experimental error, it follows that the CMB and BAO determinations can alternatively be thought as for a decelerating universe. Thus, as was noted in [1], there is an ambiguity in the CMB and BAO determinations of H 0 . To resolve this ambiguity, it was noted that the SHoES local distance ladder (LDL) determination (Note: Formerly described as cosmic distance ladder (CDL) determination.)…”

“…In the previous work [1] that dealt with the disagreement about the Hubble con-stant H 0 , it was proposed that the cosmic microwave background (CMB) [2] and the baryon acoustic oscillation [BAO] [3] values for H 0 , although based on the flat ΛCDM model of an accelerating universe, with the dark energy possessing a negative pressure supplied by the cosmological term [4] [5] [6], could alternatively be interpreted as being for a decelerating universe, with the dark energy possessing rather an index of refraction, as described in previous works [7] [8] [9] [10]. It was pointed out that this alternative interpretation was possible because the CMB and closely matched BAO determinations do not involve the deceleration parameter q 0 , and hence they are distance determinations of H 0 , as was shown explicitly in [1] for the BAO determination. Consequently, if an alternative model based on a decelerating universe can get the same distances, to within experimental error, it follows that the CMB and BAO determinations can alternatively be thought as for a decelerating universe.…”

“…Importantly, it is possible to verify the above re-interpretation of ( ) , appropriate to the Einstein de Sitter (EdS) decelerating universe, to see whether the subsequently revised value of the Hubble constant comes down reasonably close to the lower CMB value. In Equation (10) in [1] it was shown that the logarithms for the ratio of the Hubble constants for the two different values of the deceleration parameter q 0 could be written as…”

“…This discussion will include a less ad hoc explanation for the relatively short arrival time difference between photons and neutrinos from SN1987a than what was given in [10]. Also, in Section 2, a possible objection to the model (not referenced in [1], but in [12]) will be taken up that is based on the 3σ correlation of gamma rays with a neutrino that was possibly emitted from a blazar that was flaring at the time [14]. Importantly, because of the cosmological distances involved, such a correlation, if confirmed by later work, would falsify the proposed model.…”

“…It was also shown in [1] that if in the determination of ( ) 0 LDL H a positive deceleration parameter was employed rather than a negative one, ( ) 0 LDL H could be brought down towards ( ) 0 CMB H , to within a correction involving the ratio of the distances for the two models for a given redshift, with the decelerating model requiring a greater distance. It was therefore suggested in [1] that astronomers should re-determine the distances in the LDL work, to see whether, when this was done, and the decelerating parameter changed from one for an accelerating universe to one for a decelerating universe, the resulting new value of H 0 would agree with ( ) 0 CMB H . This suggestion was further described in a contributed talk [12] delivered at the American Physical Society April 2019 meeting, as will be discussed further below.…”