Two different explanations were proposed for the Hubble Constant: a decrease in starlight energy per distance caused by either a galactic recession or an absorption of starlight by the space medium. These explanations are commonly known as Big Bang and Tired Light. Big Bang was accepted in view of it being in compliance with a Tolman Brightness Test, assuming the measure of distance for the Hubble Constant is the same for light intensity and redshift, whereas decreased energy of Tired Light is proportional to light energy that decreases for the average redshift to decrease for longer distance. At the time, the redshift was calculated as constant with distance for a particular age of the universe. However, astronomical observation now indicates there was less redshift in the past than there is now.
Big Bang indications are the rate of galactic expansion has increased, which is in contrast of a future decrease of the Hubble Constant because of longer distance between galaxies or galactic clusters from continual expansion. Dark energy is proposed to explain this increased rate of expansion. Dark energy could very well exist, but there is no need of it according to Tired Light since the average rate of the Hubble Constant decreases with longer distance, that of the past according to Big Bang.
There would also be no need of a singularity, which is beyond the laws of physics and is a stumbling block of a unified field theory. Special relativity unified mechanics and electrodynamics. To include gravity, what is needed is an Addition of Gravitational Potentials Theorem in analogy to the Addition of Velocities Theorem of Special Relativity, as contrary to black holes and the singularity, and as similar to a normalization principle of Quantum Electrodynamics. Hawking modified the black hole condition whereby black holes evaporate by emitting Hawking radiation, which complies with energy conservation inasmuch as the work energy of gravity requires a loss of energy in some form.
Another argument against Tired Light is the visibility of the distant stars would be distorted by photons interacting with space. How, then, do images pass through cable and the atmosphere for clear view of countless televisions? Electromagnetic light waves consist of an interaction between electric and magnetic charge, which is bipolar, and magnets divide into tinier magnets. Electromagnetic transmissions of light could be analogous to tiny magnets dividing and multiplying to induct continuous effect without distortion other than the redshift of reduced energy.
Another argument is the photoelectric effect whereby a particular photon frequency causes the recoil of electrons from metals. However, frequency is also a wave property and the recoil is an inelastic collision whereby the metals absorb photons and emit electrons in their place. An inelastic collision of a lesser frequency can also occur whereby the molecules of the metal have time to pass on kinetic energy of light as heat, instead of emitting. Light energy thus has both continuous change of motion as well as quantum effect.
An argument in favor of Tired Light is that it provides a viable explanation of gravity. Assume mass consist of wave packets of superimposed light energy. If they reflect more frequent light in one direction and less frequent light in the opposite direction, in allowing other frequencies of light to propagate through, then they maintain relative motion in states of equilibrium. There is also internal action of the wave packets for the equivalence of gravitational and inertial mass. In the wake of emitted radiation is a vacuum effect. There is also a recycling process according to Tired Light. The gradual loss of light energy provides a long range effect for a relatively weak force in comparison to other forces of nature. The lost energy also provides a containment force of virtual energy for maintaining existence of matter in its atomic form.
In support of this argument is a mathematical relation of gravitational force in ratio to electromagnetic force. If the value of the Hubble Constant is about 70 kilometers per second at a distance of one million parsecs, then its value in ratio to light speed at a distance equal to the nuclear diameter of the hydrogen atom compares to that of the ratio of gravitational force to electrostatic force between the electron and proton of the hydrogen atom. The gravitational constant itself of an arbitrary mass unit slightly different than a gram, per centimeter squared and per light speed results in a change in speed value equal to that of the Hubble Constant at the distance equal to the nuclear diameter of the hydrogen atom.

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