Posts Tagged vacuum
Why is the speed of light constant in the vacuum?
The constancy of the speed of light c in the vacuum was the key insight in Einstein’s work on relativity. However this was an assumption, rather than a proof. It is an assumption that has worked well, in that the resulting theory has shown good agreement with many observations. The Michelson-Morley experiment directly tested the idea of Earth moving through a stationary ether, by looking for differences in the speed of light in different directions, and found no evidence to support such a theory. There is no empirical evidence that convincingly shows the speed of light to be variable in-vacuo in the vicinity of Earth. However it is possible that the speed of light is merely locally constant, and different elsewhere in the universe. In our latest paper we show why this might be so.
Fundamental questions about light
There are several perplexing questions about light:
- What is the underlying mechanism that makes the speed of light constant in the vacuum?
- What properties of the universe cause the speed of light to have the value it has?
- If the speed of light is not constant throughout the universe, what would be the mechanisms?
- How does light move through the vacuum?
- The vacuum has properties: electric and magnetic constants. Why, and what causes these?
- How does light behave as both a wave and particle? (Wave-particle duality)
- How does a photon physically take two different paths? (Superposition in interferometers)
- How does entanglement work at the level of the individual photon?
These are questions of fundamental physics, and of cosmology. Consequently there is on-going interest in the speed of light at the foundational level. The difficulty is that neither general relativity nor quantum mechanics can explain why c should be constant, or why it should have the value it does. Neither for that matter does string/M theory. Gaining a better understanding of this has the potential to bridge the particle and cosmology scales of physics.
Is the speed of light really constant? Everywhere? At all times?
There has been ongoing interest in developing theories where c is not constant. These are called variable speed of light (VSL) theories [see paper for more details]. The primary purpose of these is to explore for new physics at deeper levels, with a particular interest in quantum-gravity. For example, it may be that the invariance of c breaks down at very small scales, or for photons of different energy, though such searches have been unsuccessful to date. Another approach is cosmological. If the speed of light was to be variable, it could solve certain problems. Specifically, the horizon, inflation and flatness problems might be resolved if there were a faster c in the early universe, i.e. a time-varying speed of light. There are several other possible applications for a variable speed of light theory in cosmology.
However there is one big problem:
In all existing VSL theories the difficulty is providing reasons for why c should vary with time or geometric scale.
The theories require the speed of light to be different at genesis, and then somehow change slowly or suddenly switch over at some time or event, for reasons unknown. None of the existing VSL theories describe why this should be, nor do they propose underlying mechanics. This is problematic, and contributes to existing VSL theories not being widely accepted.
Cordus theory predicts the speed of light is variable, and attributes it to fabric density
In our paper [apr.v8n3p111] we apply the non-local hidden-variable (Cordus) theory to this problem. It turns out that it is a logical necessity of the theory that the speed of light be variable. The theory also predicts a specific underlying mechanism for this. Our findings are that the speed of light is inversely proportional to fabric density. This is because the discrete fields of the photon interact dynamically with the fabric and therefore consume frequency cycles of the photon. The fabric arises from aggregation of discrete force emissions (fields) from massy particles, which in turn depends on the proximity and spatial distribution of matter.
This theory offers a conceptually simply way to reconcile the refraction of light in both gravitational situations and optical materials: the density of matter affects the fabric density, and hence affects the speed of light. So when light enters a denser medium, say a glass prism, then it encounters an abrupt increase in fabric density, which slows its speed. Likewise light that grazes past a star is subject to a small gradient in the fabric, hence resulting in gravitational bending of the light-path. Furthermore, the theory accommodates the constant speed of light of general relativity, as a special case of a locally constant fabric density. In other words, the fabric density is homogeneous in the vicinity of Earth, so the speed of light is also constant in this locality. However, in a different part of the universe where matter is more sparse, the speed of light is predicted to be faster. Similarly, at earlier time epochs when the universe was more dense, the speed of light would have been slower. This also means that the results disfavour the universal applicability of the cosmological principle of homogeneity and isotropy of the universe.
The originality in this paper is in proposing underlying mechanisms for the speed of light. Uniquely, this theory identifies fabric density as the dependent variable. In contrast, other VSL models propose that c varies with time or some geometric-like scale, but struggle to provide plausible reasons for that dependency.
This theory predicts that the speed of light is inversely proportional to the fabric density, which in turn is related to the proximity of matter. The fabric fills even the vacuum of space, and the density of this fabric is what gives the electric and magnetic constants their values, and sets the speed of light. The speed of light is constant in the vicinity of Earth, because the local fabric density is relatively isotropic. This explanation also accommodates relativistic time dilation, gravitational time dilation, gravitational bending of light, and refraction of light. So the speed of light is a variable that depends on fabric density, hence is an emergent property of the fabric.
The paper is available open access: http://dx.doi.org/10.5539/apr.v8n3p111
The fabric density concept is covered at http://dx.doi.org/10.2174/1874381101306010077.
The corresponding theory of time, which predicts that time speeds up in situations of lower fabric density, is at http://dx.doi.org/10.5539/apr.v5n6p23.
Citation for published paper:
Pons, D. J., Pons, A. D., & Pons, A. J. (2016). Speed of light as an emergent property of the fabric. Applied Physics Research, 8(3): 111-121. http://dx.doi.org/10.5539/apr.v8n3p111
Original work on physics archive (2013) : http://vixra.org/abs/1305.0148
Fine structure constant α
This is a dimensionless constant, represented with the symbol α (alpha), and it relates together the electric charge, the vacuum permittivity, and the speed of light.
The equation is as follows:
The impedance of free space is Zo = 1/(εoc) = 2αh/e2, with electric constant εo (also called vacuum permittivity), the speed of light in the vacuum c, and the fine structure constant α = e2/(2εohc), with elementary charge e [coulombs], Planck constant h, and c as before. All these are generally considered physical constants, i.e. are fixed values for the universe.
One example of how this relationship may be used is as follows. Given the electric charge, and the vacuum permittivity, then the alpha equation may be used to explain why the speed of light has the value it does. The equation may be rearranged into other equivalent forms.
What is the physical meaning of the fine structure constant?
This is a more difficult question, especially when coupled with the question, Why does alpha take the value it does? This is something of a mystery.
We believe we can answer some parts of this question. In a recent paper of the Cordus theory it has been proposed that both the vacuum permittivity and the speed of light are dependent variables, and situationally specific. It is proposed that εo represents the density of the discrete forces in the fabric, and thus depends on the spatial distribution of mass within the universe. Thus the electric constant is recast as an emergent property of the fabric, and hence of matter.
From this perspective α is a measure of the transmission efficacy of the fabric, i.e. it determines the relationship between the electric constant of the vacuum fabric, and the speed of propagation c through the fabric.
This is consistent with the observation that α appears wherever electrical forces and propagation of fields occur, and this includes cases such as electron bonding.
The reason the speed of light is limited to a certain finite value is explained by this theory as a consequence of the fabric density creating a temporal impedance. Thus denser fabric results in a slower speed of light, and this is consistent with time dilation, and optical refraction generally. In the Cordus theory the speed of light in turn is determined by the density of the fabric discrete forces and is therefore locally consistent and relativistic, but ultimately dependent on the past history of matter density in the locally available universe. Thus the vacuum (fabric) has a finite speed of light, despite an instantaneous communication across the fibril of the particule. This Cordus theory is consistent with the known impedance of free space though comes at it from a novel direction.
The implications are the electric constant of free space is not actually constant, but rather depends on the fabric density, hence on the spatial distribution of matter. The fabric density also determines the speed of light in the situation, and α is the factor that relates the two for this universe. It would appear to be a factor set at genesis of the universe.
Pons, D. J. (2015). Inner process of Photon emission and absorption. Applied Physics Research, 7(4 ), 14-26. doi:http://dx.doi.org/10.5539/apr.v7n4p24