From the Big Bang to the Intergalactic Medium: Notes from a Cosmological Brainstorming

PREFACE: The present manuscript was not conceived as a conventional scientific article. It emerged gradually from a collection of teaching notes, personal reflections, technical discussions, and exploratory ideas developed while attempting to explain cosmological concepts to first-year Telecommunications Engineering students.The starting point was remarkably simple: an electrical analogy intended to provide an intuitive picture of the Big Bang. Using the transient response of a superconducting inductive circuit, the objective was merely to illustrate how a sudden release of stored energy might help students visualize the earliest stages of cosmic evolution. However, as often occurs in scientific inquiry, one question led naturally to another. What began as a pedagogical exercise progressively expanded into a broader investigation of modern cosmology.Throughout this process, concepts traditionally belonging to different disciplines became interconnected. Electromagnetic theory, signal propagation, Fourier analysis, General Relativity, Quantum Field Theory, cosmological observations, the Cosmic Microwave Background, the Intergalactic Medium, and the nature of the quantum vacuum gradually converged into a single intellectual thread. The result is not a unified theory, nor an attempt to challenge established physics, but rather a record of the questions, analogies, and conceptual pathways that emerged during that exploration.Several sections of this manuscript review well-established physical knowledge and are intended primarily for educational purposes. Other sections discuss unresolved questions currently under active investigation within the scientific community. In such cases, the discussion is deliberately exploratory and should be understood as a brainstorming exerciserather than as a claim of established fact. Wherever speculation appears, it is explicitly identified as such. The reader will therefore encounter a mixture of pedagogy, literature review, engineering intuition, physical interpretation, and open-ended reflection. This hybrid character is intentional. The manuscript seeks to preserve the creative process that generated it rather than rewriting that process into the more rigid structure of a conventional research article.If these notes achieve any objective, it is not to provide definitive answers, but to illustrate how curiosity, interdisciplinary thinking, and respect for observational evidence can guide the exploration of some of the deepest questions in cosmology. In that sense, the document may be viewed as a scientific travel diary: a record of an intellectual journey that begins with a simple electrical circuit and ultimately arrives at the vast emptiness of the Intergalactic Medium.