TL;DR: In this article, it was shown that Lorentz covariance and the space-time construct are consistent with the existence of a dynamical 3-space, and "absolute motion".
Abstract: We report the discovery of an exact mapping from Galilean time and space coordinates to Minkowski spacetime coordinates, showing that Lorentz covariance and the space- time construct are consistent with the existence of a dynamical 3-space, and "absolute motion". We illustrate this mapping first with the standard theory of sound, as vibra- tions of a medium, which itself may be undergoing fluid motion, and which is covari- ant under Galilean coordinate transformations. By introducing a di erent non-physical class of space and time coordinates it may be cast into a form that is covariant under "Lorentz transformations" wherein the speed of sound is now the "invariant speed". If this latter formalism were taken as fundamental and complete we would be lead to the introduction of a pseudo-Riemannian "spacetime" description of sound, with a metric characterised by an "invariant speed of sound". This analysis is an allegory for the development of 20th century physics, but where the Lorentz covariant Maxwell equa- tions were constructed first, and the Galilean form was later constructed by Hertz, but ignored. It is shown that the Lorentz covariance of the Maxwell equations only occurs because of the use of non-physical space and time coordinates. The use of this class of coordinates has confounded 20th century physics, and resulted in the existence of a "flowing" dynamical 3-space being overlooked. The discovery of the dynamics of this 3-space has lead to the derivation of an extended gravity theory as a quantum e ect, and confirmed by numerous experiments and observations. It is commonly argued that the manifest success of Lorentz covariance and the spacetime formalism in Special Relativ- ity (SR) is inconsistent with the anisotropy of the speed of light, and indeed the existence of absolute motion, that is, a detectable motion relative to an actual dynamical 3-space, de- spite the repeated experimental detection of such e ects over, as we now understand, more than 120 years. This apparent incompatibility between a preferred frame, viz a dynamical 3-space, and the spacetime formalism is explicitly resolved by the discovery of an exact mapping from Galilean time and space coordinates to Minkowski spacetime coordinates , showing that Lorentz covariance and the spacetime construct are indeed consistent with Galilean covariance, but that they suppress any account of an underlying dynamical 3-space. In the neo-Galilean formalism, known also as the Lo- rentzian interpretation of SR, length contraction and clock ef- fects are real e ects experienced by objects and clocks in mo- tion relative to an actual 3-space, whereas in the Minkowski- Einstein spacetime formalism these e ects are transferred to the metric of the mathematical spacetime, and then appear to be merely perspective e ects for di erent observers. Ex- periments, however, have shown that the Galilean space and time coordinates competently describe reality, whereas the Minkowski-Einstein spacetime construct is merely a mathe- See (1) and Damour (2) for discussion of Minkowski's work.
TL;DR: The existence of an invariant speed is not a necessary assumption and in fact is a consequence of the principle of relativity (though the finite value of this speed must, of course, be obtained from experiment) as discussed by the authors.
Abstract: The structure of the Lorentz transformations follows purely from the absence of privileged inertial reference frames and the group structure (closure under composition) of the transformations—two assumptions that are simple and physically necessary. The existence of an invariant speed is not a necessary assumption and in fact is a consequence of the principle of relativity (though the finite value of this speed must, of course, be obtained from experiment). Von Ignatowsky derived this result in 1911, but it is still not widely known and is absent from most textbooks. Here, we present a completely elementary proof of the result, suitable for use in an introductory course in special relativity.
TL;DR: A parameter-insensitive speed drive system which utilizes outer-loop sliding-mode control and inner-loop decoupling control of a series-connected wound-rotor induction machine (SCWRIM) is presented.
Abstract: A parameter-insensitive speed drive system which utilizes outer-loop sliding-mode control and inner-loop decoupling control of a series-connected wound-rotor induction machine (SCWRIM) is presented. The methods of decoupling control and torque linearization for the SCWRIM are outlined. Sliding-mode control with cascaded integral operation is applied to provide invariant speed responses, improved steady-state accuracy, and reduced torque chattering. The scheme is implemented using a resolver-based system for speed and position sensing. The parameter-insensitive characteristics are demonstrated through computer simulations and experimental verification. >
TL;DR: The existence of an invariant speed is not a necessary assumption, and in fact is a consequence of the principle of relativity (though the finite value of this speed must, of course, be obtained from experiment) as mentioned in this paper.
Abstract: The structure of the Lorentz transformations follows purely from the absence of privileged inertial reference frames and the group structure (closure under composition) of the transformations---two assumptions that are simple and physically necessary. The existence of an invariant speed is \textit{not} a necessary assumption, and in fact is a consequence of the principle of relativity (though the finite value of this speed must, of course, be obtained from experiment). Von Ignatowsky derived this result in 1911, but it is still not widely known and is absent from most textbooks. Here we present a completely elementary proof of the result, suitable for use in an introductory course in special relativity.
TL;DR: In this article, it was shown that a certain discreteness of space-time, whose existence is strongly suggested by the combination of quantum theory and general relativity, may result in the existence of a maximum and invariant speed when combing with the principle of relativity and thus it can determine the finiteness of the speed in the theory of relativity without light.
Abstract: The role of the light postulate in special relativity is reexamined. The existing theory of relativity without light shows that one can deduce Lorentz-like transformations with an undetermined invariant speed based on homogeneity of space and time, isotropy of space and the principle of relativity. However, since the transformations can be Lorentzian or Galilean, depending on the finiteness of the invariant speed, a further postulate is needed to determine the speed in order to establish a real connection between the theory and special relativity. In this paper, I argue that a certain discreteness of space-time, whose existence is strongly suggested by the combination of quantum theory and general relativity, may result in the existence of a maximum and invariant speed when combing with the principle of relativity, and thus it can determine the finiteness of the speed in the theory of relativity without light. According to this analysis, the speed constant c in special relativity is not the actual speed of light, but the ratio between the minimum length and the shortest time of discrete space-time. This suggests a more complete theory of relativity, the theory of relativity in discrete space-time, which is based on the principle of relativity and the constancy of the minimum size of discrete space-time.