Time, Space and Causality in Modern Physics

Modern Physics, by constraining these categories to one another, has highlighted an irreducibly discrete aspect of them. Using a metaphor, we could say that the situation is similar to one of those classic optics experiments that reveal, thanks to a wall with two holes, the interference fringes of light. As long as only one of the holes is open and light passes only through one of them, the image thus projected on the wall is simply that of light extending continuously along the entire wall. However, as soon as we open the other hole too, we obtain an image on the wall made of light lines and shadow lines, and the result thus appears inevitably discontinuous. In the same way, Modern Physics, wanting to study the relationships existing between these concepts, wanting to open both holes of the wall simultaneously, has lost the continuous and absolute structure of space, time and causality to derive a discontinuous and relative structure from them. In the following pages we will summarize all these concepts in some simple formulas, which represent an indispensable basis of all modern physics. The first of these relates to the link between space and time postulated by Einstein, the second and third involve Energy and Causality instead. The complete explanation of these formulas and their derivation clearly exceeds the scope of this book, however all the reasoning and results that we will present subsequently will have these fundamental laws as an unwaiverable prerequisite. For this reason we have made sure that the reader can familiarize themselves with them as soon as possible and get used to digesting the new concepts. 1.1 The Nature of Space and Time
The Supreme Lord said: I am Time, fierce destroyer of worlds
Bhagavad Gita 11.32 Time certainly represents one of the most fascinating mysteries for consciousness. It in fact separates with a sharp line what is known, the past, from what is unknown, the future, and at the frontier of these two quantities, in the present, it inexorably binds our consciousness to them. Our external senses, in fact, are all polarized in the present instant and if we want to detach ourselves from it we must resort to inner faculties such as memory, logical reasoning or intuition that try to bring realities of a distinct temporal order back to the present state. Our consciousness, therefore, flows with the flow of time, gaining experiences without respite and advancing to the limit of the unknown beyond which the future rests. Time therefore represents a great mystery for all speculative minds that have always sought to understand its origin and penetrate its secrets. In antiquity, Time was naturally associated with the Sun, its natural sign, and, as such, considered as a deity. The Egyptians, for example, used the symbol of the sun as a temporal determinative and it is difficult to distinguish the two concepts from each other. In ancient Greece, instead, time gains its autonomy becoming Kronos, the Roman Saturn, father of Zeus who devours his children. In the India collected from the Bhagavad-Gita it is Krishna himself, the eternal avatar, who reveals himself to Arjuna declaring "I am Time". Alongside the metaphysical and religious investigation of time, its philosophical investigation was then structured. Plato, for example, defines it as a mobile image of eternity, highlighting its self-similar aspect. Zeno, for his part, drastically denies its existence, while Heraclitus sanctions its supremacy. And so from the founding fathers of philosophy, the study of time has continued, passing through hundreds of authors and philosophers, crossing the thresholds of psychology with Bergson, those of physiology with Mach to finally reach the kingdom of Physics with Einstein's space-time hypothesis. Here the history of space and the history of time, which until then had had two parallel lives with fleeting intersections, are indelibly united. The first philosopher to conceive space as indissolubly linked to time was probably Origen, one of the greatest theologians of all time, who lived in Alexandria, Egypt between the 2nd and 3rd centuries after Christ. He was the first to structure in an articulate and coherent way the concept of time as extension, endowed with a certain length or as a path that must be completed. Since the time of Origen, the links between space and time have alternately followed each other, approaching and separating until the edge of the 19th century. In this period the widespread idea began to emerge that space and time could be linked by some intimate relationship. Emblematic in this sense are the words of Edgar Allan Poe, in that cosmological-literary jewel called Eureka, in which, laying the foundations for a new cosmology, the author explicitly declared that "space and duration are one". Poe's writing certainly represents a curious writing that, as we will see, had the merit of anticipating many of the ideas of modern cosmology. However, precisely because of its visionary character, this writing appeared very confused at the time and was little considered by the scientific community. The first true formulation of a close link between space and time that could be accepted by the contemporary scientific community is instead due to Albert Einstein in what was then indicated as the theory of Special Relativity. On the theory of Special Relativity, on its foundational bases and on its implications...