Tom is a physical scientist as well as a computer and theoretical scientist with a broad range of interests, experiences, and knowledge that fuel his passion for investigative problem solving.

Metropolitan State College of Denver

Chemistry BS, Metropolitan State College of Denver

Chemistry, Quantum Mechanics, Forensic Science, AI & Computer Science, Multidisciplinary Investigation

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Reconsidering the Concept of a Medium in Modern Physics: The Electromagnetic Field's Role in Light Propagation

Author: Tom DeGerliaDate: September 15, 2024IntroductionThe concept of a “medium” for light propagation was put to rest over a century ago, since the famous Michelson-Morley experiment in 1887, which attempted to detect the presence of the “luminiferous ether.” The failure of the experiment to confirm the ether’s existence led to the wholesale rejection of the idea that light requires a medium to travel through space. While based on scientific evidence, this rejection has evolved into something more: a social and philosophical rejection of the very notion of a medium. Yet, in modern physics, particularly Quantum Field Theory (QFT), the role of the electromagnetic field in the transmission of electromagnetic energy closely mirrors that of a medium, even if we refer to it by a different word.This demonstrates that subjecting scientific conclusions to popular opinion or any other social factor obstructs objective scientific discourse. While this technique can effectively control competing interests, it imparts a non-scientific bias into the scientific process that obstructs objective research and merit-based debate. My goal with this article is to shed light, via the history of the luminiferous ether debate, on how a clash between generations of physicists over the nature of light transmission resulted in a century of missed opportunities to better understand electromagnetic radiation.Clash of the PhysicistsIn the late nineteenth century, classical scientists believed that light, as a wave, required a medium to propagate, much like sound propagates through air. This hypothetical substance, the “luminiferous ether,” was thought to fill all space and provide the medium through which light propagates.Classical physicists felt strongly that light could be understood in classical terms and believed light to convey via a medium. Modern physicists describing light behavior from quantum and relativistic standpoints were at odds with classical physicists. This resulted in the marginalization of modern physicists initially, and after being ratified by a series of achievements, including the atomic bomb, the backlash against classical physicists was strong.The Historical Rejection of the EtherHowever, when the 1887 Michelson-Morley experiment failed to detect any evidence of this ether, it was concluded that no such medium existed. The negative results of this experiment were seen as a victory for modern physicists and a defeat for classical physicists. They paved the way for Einstein’s theory of special relativity in 1905, which showed that light could propagate in a vacuum without needing an ether.Einstein’s work revolutionized physics, but the resulting near-total rejection of the medium concept has distracted from the facts and threatens to perpetuate misinterpretations that don’t consider what could be a more nuanced reality. According to the prevailing interpretation at the time, and as demonstrated by the Michelson-Morley experiment, electromagnetic radiation (like light) was defined as a form of energy that travels through the “vacuum of space” unobstructed, with space itself not offering any resistance or medium-like qualities. This interpretation led to the necessity for the photon, which was proposed by Einstein not as a definitive explanation but as one plausible hypothesis based on experimental outcomes.The Electromagnetic Field: The Modern InterpretationAs our understanding of physics evolved, particularly with the development of Quantum Field Theory (QFT), the idea of fields became central to how we describe forces and particles. The electromagnetic field, for instance, is now understood as a pervasive entity that governs the behavior of charged particles and the propagation of electromagnetic radiation, including light.In classical physics, the electromagnetic field describes the region of space where electric and magnetic forces operate. With the development of QFT, the electromagnetic field is more fundamental; light itself is now understood as quantized excitations of this field, commonly referred to as photons. Light, therefore, does not simply travel through empty space but is a manifestation of the interactions within the electromagnetic field.This leads us to a question: if the electromagnetic field plays the same functional role in light propagation that classical physicists ascribed to the ether, why is it still considered inappropriate to refer to it as a “medium”? The answer is rooted in the social and historical rejection of the ether rather than the physics itself.Social Rejection vs. Factual RejectionThe rejection of the ether wasn’t just a scientific rejection; it became part of the philosophical and social fabric of modern physics. The word “medium” itself became associated with outdated ideas and the failures of classical physics to explain the nature of light. The scientific community was eager to embrace the new, more elegant solutions of relativity and quantum mechanics, and with them came the rejection of anything resembling the ether.But this rejection was never a factual one in the broader sense. While the luminiferous ether, as initially conceived, did not exist, under QFT the electromagnetic field serves a very similar purpose in modern physics. It fills space, interacts with matter, and governs the propagation of electromagnetic waves. To deny that this field behaves in some ways like a medium is to ignore the underlying physical reality.Revisiting the Medium ConceptIt’s time to reconsider the term “medium” in light of what we now know about fields and forces in physics. The electromagnetic field acts as the substrate through which electromagnetic waves propagate, and in that sense, it fulfills the role of a medium.We don’t need to return to the outdated and debunked notion of a luminiferous ether, but we should recognize that our rejection of the word “medium” is based more on the historical baggage of the ether than on the realities of how light and fields interact. The electromagnetic field, as described by QFT, is a modern and more accurate representation of what physicists once sought to describe with the ether, but we can’t allow semantics to get in the way of understanding its true nature.Conclusion: Break Free from Semantic BiasThe scientific community’s aversion to the word “medium” is rooted more in history than in science. The electromagnetic field acts in ways that are similar to what classical physicists imagined for the ether—it is a pervasive field that allows the propagation of electromagnetic energy. Acknowledging this does not mean returning to pre-relativity physics, but rather embracing a more nuanced understanding of the role that fields play in the universe.For over a century, since the luminiferous ether was invalidated, in our rush to discredit the old and usher in the new, we made the presumption that there is a vacuum of space and a need for electromagnetic energy to be conveyed via particle and, therefore the photon. While this picture may prove accurate, there is no reason in science to extend that status in advance of this proof.Ultimately, this is not about resurrecting outdated ideas but about letting go of a bias that has no basis in modern physical theory. The electromagnetic field is, in effect, a medium, and recognizing this can only enhance our understanding of the fundamental nature of light and energy.References• Einstein, A. (1905). Concerning an heuristic point of view toward the production and transformation of light. Annalen der Physik, 17, 132–148.• Feynman, R. P. (1985). QED: The strange theory of light and matter. Princeton University Press.• Michelson, A. A., & Morley, E. W. (1887). On the relative motion of the earth and the luminiferous ether. American Journal of Science, 34(203), 333–345.• Zee, A. (2010). Quantum field theory in a nutshell. Princeton University Press.• Navarro, J. (2010). Killed by its own obituaries: Explaining the demise of the ether. Science in Context, 23(2), 175–203.

Reconsidering the Concept of a Medium in Modern Physics: The Electromagnetic Field's Role in Light Propagation

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