Since the whole of cosmology depends on interpretation of the red shifting of light from distant galaxies the red shift has to be defined first. There are two causes for red shifting which add (or subtract), one by radial movement, Doppler, and one caused by loss of momentum sometimes called 'tired light' There is a small collection of galaxies which are blue shifted and they are closer to us, one of them being our nearest neighbour Andromeda.

Andromeda M31 Galaxy (Image credit NASA)
Andromeda M31 Galaxy (Image credit NASA)

Doppler leads to an expanding, finite universe arising from an unexplainable beginning and the other to a universe infinite in time and space and mass without a beginning or an end, but incomprehensible.

Red And Blue Shift Distance Related And True Dopple

Examining a particular star in detail in a telescope shows it looks brighter not larger. It could be variable, which has its interests, but finding out more means studying its colour by spectroscopy, Colours can be separated by a prism red at cooler, longer wavelengths through orange green to blue at shorter wavelengths of greater energy.

Elements emit bands of light in different colours usually several highly distinctive colours which accurately identify it. If light travels through a cloud of the element black lines are left in the spectrum in the same places as the element's emission lines. identifying positively the element in the cloud usually the star's atmosphere.

Diagram showing red shifting
Diagram showing red shifting

Hubble found that identifiable spectral lines were moved into different colours towards the red, red shifting. This could be interpreted as either Doppler or 'tired light' each of which would produce a different cosmology. Doppler red shifting implied an expanding universe with a beginning and a finite cosmology and tired light interpretation meant a static universe without expansion no beginning and an infinite universe. A collision body can cause the red shifting such as a charged particle as described by Compton in 1923, but they also scatter the photon, which eliminates plasma as a red shifting agent. Uncharged particles cannot be shown to red shift even if there were enough of them in space. Or neutrinos which are very unreactive. Other photons such as the CMB which, when the source is considered in wave, form would give some but not enough red shifting, but in photon mode and travelling alone, possibly could.

Leaving gravity to consider. Steinhardt and Turok point out in their book 'The Endless Universe', that photons after emission as particles get themselves by interference into wave mode and travel until very faint (which light would be from distant galaxies), when they then continue on as single photons.

Thus they become prone to loss of energy more readily than in a wave. (Can a single photon be red shifted by Doppler?) A parallel here would be the foam from a wave approaching the shore lingers above and behind the wave or precedes it often finishing miles inland.

Gravity and its field are vague and loosely accounted for by both relativity and quantum theory. Light is an enigma with its duality. Sometimes it seems to be definitely a wave and sometimes definitely a particle, a photon. Interaction of light and gravity is not considered to be significant in red shifting of light from distant galaxies or not in sufficient amount to account for the red shifting found. Thus there are two rather mysterious media escaping attention.

Einstein said gravity must red shift light otherwise relativity is invalid. Observations show gravity does red shift, but enough? When gravity is obviously high as it is close to the sun or even by experiment on earth, it can be shown to be significant and measurable but is it through intergalactic space? Gravity as a force is apparently static varying only as the mass it goes with varies, which is very little. Its density is unknowable being due to the sum of all mass near and far. Gravity to infinity and in an infinite number of directions adds together balancing but never cancelling out. The state of zero gravity as in an aeroplane in a weightless arc has its gravity balanced by an acceleration but the force of gravity is still there. The density of gravity in a spot apparently at zero could be considerable, as in the Lagragian point 1 apparently zero gravity but a high density spot.

Gravity at any one spot is immeasurable. It could be high, enough to expect a significant cross section with photons traversing the same space in trajectory in a stationary field. It could be that 'light' measures this cross section, as red shifting - are we seeing the result before us?

It is possible to reach the same conclusion on red shifting of light from distant galaxies as did Professor David Crawford of the University of Sydney NSW who used different parameters and 'Curvature pressure' as a basis of his more scientific approach in the Australian J. Phys, 1999,52.753, and concluding that a non Doppler cosmology could be postulated which fitted the observation better than an expanding theory.

Both light and gravity are related according to the inverse square law and both are related to mass, gravity directly and light through the intensity of electromagnetic radiation from cosmic mass both luminous and non-luminous – of starlight and of the CMB. The density of gravity in intergalactic space would be a background level (the Cosmic Gravity Density?)

Photons collide with photons in gamma gamma colliders, some losing energy and cross sections here are known at one microbarn which varies with frequency, being high at high energies tailing off at lesser energies then rising again to even higher levels.

Photons themselves particularly photons of the CMB must be considered as colliding objects. Radio waves, in particular 21 cms from hydrogen, are also red shifted (increased wavelength) in a distance related fashion meaning that gravity is probably the greater factor as the red shifting body.

Using the formula Loss of momentum implies a constant distance to red shift a standard amount, say Z=1=halving the frequency. It would be several billion light years - this may not be a constant for all frequencies which could not happen for red shifting by expansion.

The red shifting of light considered as a wave suggests that Doppler is the mechanism but this becomes doubtful when recession at velocities greater than the speed of light itself results. Fixing this by suitable equations meaning that the spacetime the body is emitting from is expanding at this velocity makes it not true Doppler only an analogy.

It is not easy to tell whether observed red shifting is recessional (Doppler) or only distance related (tired light) as things thought to be moving cannot be shown to have moved in the short time observed, a mere one hundred years. On the other hand there are strong leads that distance related galaxies, excluding the local group, are red shifted in a manner which could not be from expansion (see Webb).

The infinite universe theory needs some mathematics to link mass density of overall space with the actual energy loss of light in particle mode, a problem of no concern to a finite cosmology. This may have been done already without reaching the light of day.