Relativity: General and Special Relativity (Full Translation with Color Illustrations and Detailed Explanations)

Author: Albert Einstein (USA)
Publisher:
Publish Date: 2006-11-01
Features: This is a book that discovers and creates a new order of the universe not with the eyes but with wisdom. It reveals the extraordinary secrets of the universe: the relativity of simultaneity; the time dilation and length contraction effects in motion; the perihelion precession of Mercury; the redshift of the spectrum; the slowing of clocks in gravitational fields, etc. – this is Einstein's "Theory of Relativity"! It completely overturned classical physics, opening up a brand-new physical world for humanity. This is not only one of the few revolutionary leaps in the history of science but also the beginning of a myth in an era! This is a book that completely subverts the concepts of classical physics. It negates Newton's absolute space and time, proposing that space is not a flat Euclidean space but a curved Riemann space in a gravitational field; time is not a separate dimension independent of space, but it is always present within space, forming a unified four-dimensional spacetime continuum. Additionally, on the basis of concise compilation and accurate compression, the key points of the book are vividly supplemented in a graphical manner, highlighting the essential ideas of the original author while avoiding the academic complexity that confuses many readers.
The discovery of quantum mechanics, therefore, did not end the revolution that was initiated by the introduction of the "field." At the turn of the century, a fundamental crisis occurred that was unrelated to what we just discussed, brought to light by Max Planck's research on thermal radiation (1900), which suddenly revealed its severity. The historical significance of this event is noteworthy because, at least in the early stages, it was not influenced by any remarkable experimental discoveries. Based on thermodynamics, Kirchhoff concluded that the energy density and spectral composition of radiation in an opaque container with wall temperature T are independent of the properties of the walls. That is to say, the density of monochromatic radiation is a universal function of frequency and absolute temperature. This raises an interesting question: how to determine this function. What can we theoretically determine about this function? According to Maxwell's theory, radiation must exert pressure on the cavity walls, and this pressure is determined by the total energy density. From this point, Boltzmann deduced, using purely thermodynamic methods, that the total energy density of radiation is proportional to T. Thus, he provided theoretical justification for the law previously discovered empirically by Stefan – he linked this empirical law to the foundation of Maxwell's theory. Subsequently, Wien applied Maxwell's theory, conducted creative thermodynamic thinking, and also discovered the elegant form of a universal function containing two variables. One of the universal constants led to quantum theory. A constant in Planck's formula accurately gave the true size of the atom. Planck was clearly aware that this was a great success. However, there was a serious flaw, fortunately, which Planck did not notice at the time. For the same reason, the Planck formula should also apply to low-temperature states. However, if that were the case, the formula would be ruined. Therefore, from the existing theory, the correct conclusion should be that the average kinetic energy of the oscillators given by the gas theory is wrong. That would mean denying (statistical) mechanics, or by Maxwell's theory, the average kinetic energy of oscillators is wrong, which would mean abandoning Maxwell's theory. In such a situation, it is possible that both theories are only correct within a limited range and not otherwise. This is indeed the case. If Planck had reached such a conclusion, he would not have made his great discovery, because it would have deprived his purely theoretical thinking of its foundation.
Now, let's return to Planck's reasoning. According to the kinetic theory of gases, Boltzmann had already discovered that, apart from a constant factor, entropy is equal to the logarithm of the "probability" of the state under consideration. Through this perspective, he recognized that processes are "irreversible" in a thermodynamic sense. However, from the perspective of molecular mechanics, all processes are reversible. If one calls the state defined by molecular theory the "microscopic state" or simply "microstate," and the state described by thermodynamics the "macrostate," then there are countless states that belong to the macrostate. This idea is particularly important because its scope of application is...