The book The Fifth Force was written by Thomas S. Kakovitch in 2012 to address the physical essence of force in case the existence of mass, electric charges, and the variety of nuclear charges is not taken into account. The author focuses on the nature of force prior to the existence of these forces by stating that the four fundamental forces such as the strong nuclear, weak nuclear, electromagnetic, and gravity forces are not the only ones existing in nature. The firth force he speaks about is that of a scalar force field, the function of temperature, existed after the big bang and before the emergence of four forces taken as the fundamental scope of forces by the modern physics theory.

The initial point from which Kakovitch derived his argument was the concept of field as described in the General Theory of Gravity and the Quantum theory (Kakovitch 3). Starting his argument from considering the laws of nature invariant in regard to Lorentz transformations, i.e., the scientific rationale for the explanations of the speed of light observed regardless of the reference frame, and giving the understanding of the electromagnetism laws’ symmetries, Kakovitch continued by assuming that the concept of space has long been challenged by scholars. Citing the work of Mach who distanced from the concept of space and replaced it with the notion of the “totality of the instantaneous distances between all material points”, Kakovitch pondered on the issue of what would remain if the whole material were removed, and how the totality of distances about which Mach spoke in his research would be analyzed in the condition of the ponderable matter’s absence (Kakovitch 3).

Here is the point at which Kakovitch arrived at the need to introduce the concept of field as a meaningful aspect of analysis; if the experimental conditions involved the removal of all material in the context of which analysis could be done, field would replace the particle, or material point, as the context of analysis (Kakovitch 4). By illustrating his point by the temperature function that acted simultaneously as the function of coordinates and time as a temperature field, Kakovitch indicated that there was no chance for the space-time continuum to exist in the absence of field with the temperature field. Relying on the theory of Einstein about the evolution of the three-dimensional existence notion and the four-dimensional continuum, the author inferred that no space-time continuum could exist without field, as it can exist only in the form of its structural quality (Kakovitch 4). The major illustration of this indispensible connection was illustrated by the dependence of space-time curvature on the scale factor encompassing the characteristics of homogeneity and isotropy into the structural quality of field in Einstein’s understanding (Kakovitch 4).

The second point of Kakovitch’s reference to the fifth natural force may be found in his discussion of the black body radiation. The interest of Kakovitch towards the concept of the black body radiation is reasonable, since it is the physical ideal used in thermodynamics for radiation research because of its ability to absorb all electromagnetic radiation issued at all ranges and not to reflect any of its amount. The spectrum of the black body’s radiation is predetermined only by its temperature, which is termed as equilibrium necessary for experimental goals by Kakovitch (7). Relating the experimental evidence about the fifth force to the black body, Kakovitch noted that the perfect black body with a temperature lower than one billion degrees centigrade could emit all sorts of particles, the coupling of which to matter for gravitational fields could hypothetically result in the formation of the black hole. However, this experimental outcome can be elicited only in case the field approaches the quantum domain (Kakovitch 7).

The emissive power of the black body is calculated according to Planck’s law of radiation that connects it to the energy density of radiation (Kakovitch 7). Kakovitch also referred to the law of Kirchhof about the emissive power of the black body, and the thermal emission’s value, as well as to the Bose-Einstein statistical distribution function to explain the emissive power of the black body. However, the author also relied on the quantum theory in the discussed aspect by stating that the black body has an infinite number of energy levels that enable it to absorb any photon incident on it (Kakovitch 7). Hence, the thermal equilibrium of the black body presupposes its ability to be an ideal emitter, and all radiated particles are characterized by possessing the quantized spins.

By referring to the general relativity theory and correlating it with Planck’s order of magnitude, Kakovitch challenged the former and stated that three coordinate axes in space-like and time-like cannot define the physics beyond the latter, especially when the general relativity theory is broken down at coordinate systems in the range of Schwarzwald radius (Kakovitch 12). By putting forward this argument, Kakovitch further stated that there is no empirical research evidence enabling the humanity to believe that every general world-frame at every point would possess four space-like line elements and one time-like element. According to the author, there is a possibility for a more randomly assigned number of coordinate axes to possess time-like and space-like features. At this point of argument, Kakovitch referred to the theory of Gödel who ascribed the time-like properties to two elements, and space-like properties – to the other two elements (Kakovitch 12).

Another field of Kakovitch’s interest is the path of light ray in the space-time that is usually referred to as the null geodesic in physics, meaning that the ray of light usually passes the straightest thus the minimal length in any curved space-time geometry (Kakovitch 15). The author admitted that in the conditions of strongly curved time-space trajectory, the distinction between gravity and black body radiation becomes blurred. Kakovitch referred to the distance between these two notions as not wide in physics, and even drew parallels for merging the principles of quantum field theory with the general relativity principles for the sake of moving towards the analysis of the fifth force in a more unified, integrated way.

The connection became possible by means of Kakovitch’s reference to the presentation of the line element with quadratic form in the general relativity theory that has a direct physical meaning (Kakovitch 15). Nevertheless, when the arc length in that equation is replaced by the proper time, the equation from the general relativity theory is transformed into “equivalent to the negative square of the speed of light with which radiation also propagates” (Kakovitch 15). By means of creating this connection between the two aspects of research, Kakovitch underlined that to bridge the gap, the range of validity of these two theories has to be defined, and general relativity should be applied to the explanation of the property matters’ duality.

Kakovitch also found the connections inherent in the Planck’s law of radiation and the principles of general relativity in the issues related to the explanation of quantum field principles. However, the major precondition that Kakovitch formulated for this connection to be valid is the ability of Planck’s Radiation Law to be transformed into the quantum field (Kakovitch 15). The present transfer is possible by means of applying Planck’s law integrated over all frequencies and wave-lengths, making it act as a temperature field, and depend only on the absolute temperature (Kakovitch 15).

Kakovitch also dedicated a part of his discussion to the Bose-Einstein distribution function by perceiving solid particles as able to emit black body radiation over all frequencies and wave-lengths. If this condition is met, electromagnetic radiation waves will be characterized by the ability of absorbing and emitting photons, which in turn will be in the thermal equilibrium with the system of particles creating and absorbing them. In these conditions, temperature function is considered scalar, and the energy density calculations are performed with the help of the Bose-Einstein function (Kakovitch 19). By asking the question of how to set the black body radiation equations only in terms of T, and by analyzing the Planck Radiation Equation, the Rayleigh-Jeans formula radiation for low frequencies, the Wien formula radiation for high frequencies with maximum risks, Kakovitch elicited two formulas of the Planck Radiation Law that represent the function of two variables, frequency and temperature, thus making his planned integration of Planck’s Radiation Law and general relativity theory possible.

The value of Kakovitch’s book about the fifth force is very high for such aspects of scholarly studies as thermodynamics, quantum physics, as well as other aspects of physics and the theory of matter and fundamental forces. Though the reading may be completely non-accessible for conventional readers because of the complexity of lexicon and reference to numerous physical and thermodynamic theories, the general idea of the work may be fascinating for both professionals and laypersons. Kakovitch took a structured approach to explaining why the fifth force exists in the world, and summarized the prior research in the field, contributing his own observations and scholarly inferences to understanding the evidence speaking for its existence.

Hence, the work is highly valuable in the professional practice because finding the experimental proof for the fifth force’s existence is very hard, and despite some successful experiments, their majority has still failed, which makes the research of the fifth force challenging but still interesting for the modern physicists. The theory of Kakovitch that the fifth force is the primal force that existed before the emergence of the four fundamental natural forces considered in physics nowadays is high intriguing. It helps to understand the processes that led to the creation of the Earth after the big bang, and sheds more light on the universal comprehension of forces existing between matter, space, and time in the modern physical reality.

Works Cited

Kakovitch, Thomas S. *The Fifth Force*. Amherst, MA: The McLean Project. 2012. Print.