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It is well known that simultaneity within an inertial frame is defined in relativity theory by a convention or definition. This definition leads to different simultaneities across inertial frames and the well-known principle of relativity of simultaneity. The lack of a universal present implies the existence of past, present, and future as a collection of events on a four-dimensional manifold or continuum wherein three dimensions are space like and one dimension is time like. However, such a continuum precludes the possibility of evolution of future from the present as all events exist "forever" so to speak on the continuum with the tenses past, present, and future merely being perceptions of different inertial frames. Such a far-reaching ontological concept, created by a mere convention, is yet to gain full acceptance. In this paper, we present arguments in favor of an absolute present, which means simultaneous events are simultaneous in all inertial frames, and subscribe to evolution of future from the present. [ABSTRACT FROM AUTHOR]

Time dilation (TD) is a principal concept in the special theory of relativity (STR). The Einstein TD formula is the relation between the proper time t 0 measured in a moving frame of reference with velocity v and the dilated time t measured by a stationary observer. In this paper, an integral approach is firstly presented to rededuce the Einstein TD formula. Then, the concept of TD is introduced and examined in view of the fractional calculus (FC) by means of the Caputo fractional derivative definition (CFD). In contrast to the explicit standard TD formula, it is found that the fractional TD (FTD) is governed by a transcendental equation in terms of the hyperbolic function and the fractional-order α. For small v compared with the speed of light c (i.e., v ≪ c ), our results tend to Newtonian mechanics, i.e., t → t 0 . For v comparable to c such as v = 0.9994 c , our numerical results are compared with the experimental ones for the TD of the muon particles μ + . Moreover, the influence of the arbitrary-order α on the FTD is analyzed. It is also declared that at a specific α , there is an agreement between the present theoretical results and the corresponding experimental ones for the muon particles μ + . [ABSTRACT FROM AUTHOR]

In special relativity, the time dilation formula has been obtained by particles propagation in a straight line trajectory relative to an observer in motion. Up to now, there are no available formulas for other possible trajectories of particles. However, this paper obtains formulas of time dilation for several trajectories of particle such as parabolic, elliptic, and circular and finds a relatively accurate trajectory. The obtained formulas are employed in order to analyze the time dilation of the muon particles decay. In this paper, it is found that the time dilation of the parabolic and the elliptical trajectories exceed the corresponding results utilizing the standard Lorentz-Einstein time dilation formula. Consequently, if we are able to control the trajectory of unstable particles by some external forces, then their life-times might be increased. Probably, the increase in lifetime via a curved trajectory occurs at lower relative velocity & acceleration energy if compared to the straight line trajectory. In addition, the circular trajectory leads to multiple values of time dilation at certain velocities of an observer in motion, which may give an interpretation of fluctuations of time dilation in quantum mechanics. The result arises from the present relatively accurate formula of time dilation that is very close to the experimental data of muon decay (CERN experiment) when it is compared to the result obtained by the Lorentz-Einstein formula. Finally, it may be concluded that the time dilation not only depends on relative velocity and acceleration energy of particles but also on curved trajectories. The present work may attract other researchers to study different trajectories. [ABSTRACT FROM AUTHOR]

This paper develops the approach to special relativity put forward by John S. Bell. The classical dynamics of an electron orbiting a nucleus in uniform motion is solved analytically and compared to numerical simulations for an accelerated nucleus. The relativistic phenomena of length contraction and time dilation are shown to result from the electric and magnetic forces on the electron when its motion is analyzed in a single frame of reference. The relevance of these results for understanding the theory of special relativity is discussed. In this paper, the author explores a suggestion by John Bell for teaching special relativity: to introduce length contraction and time dilation as dynamical phenomena arising from the laws of motion, without reference to the Lorentz transformations. The paper provides historical and philosophical insight into the development of special relativity alongside an analysis of electron orbits in a classical model of an atom. Using only the Lorentz force law, the author illustrates the deformation of orbits of moving and accelerating atoms with approximate, exact, and numerical calculations that reveal time dilation and length contraction. Instructors may find these derivations useful in teaching courses on modern physics, relativity, classical mechanics, electrodynamics, or numerical methods. [ABSTRACT FROM AUTHOR]

Einstein's special and general relativity are relics from before quantum physics. If forces are transmitted by quanta, this must also apply to gravity. As light consist of quanta, it is only logical that gravitational quanta interact with light. In my article "Cognitive bias in physics with respect to Einstein's relativity, demonstrated by the famous experiment of Pound and Rebka (1960), which in reality refutes Einstein's general relativity" [R. G. Ziefle, Phys. Essays 35, 91 (2022)], I could demonstrate that Einstein's "proper time" t0 does not refer to reference frames but to gravitational potentials. That is why "Newtonian quantum gravity" [R. G. Ziefle, Phys. Essays 33, 99 (2020)] can predict the correct curvature of a light beam at the surface of the Sun. Also, the phenomena observed at the binary pulsar PSR B1913þ16 can precisely be predicted by merely applying Kepler's second law. If gravitational quanta move away from masses with the constant speed c of light, this coincides with Einstein's postulate of a constant speed c of light with respect to reference frames, as a mass, such as a star or a planet, can also be defined as a reference frame. Therefore, Einstein's found by chance an artificial and complicated method to calculate changes in space-time caused by motion, which are in reality additional gravitational effects caused by the relative velocity between gravitational quanta emitted by masses and other masses or photons. [ABSTRACT FROM AUTHOR]

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The explanation of Einstein’s special theory of relativity in his original 1905 paper is examined. His analysis is confusing, as terms x, y, z, t, etc., have different meanings at various points, and he presents equations based on different and inconsistent assumptions. Adding subscripts clarifies these issues but exposes errors in his reasoning. To calculate his transformation equations, he selects a combination of equations which gives results matching the Lorentz transformation but he ignores other possible valid solutions. Also his calculations contain serious errors. Therefore, he fails to prove that his theory leads to the Lorentz equations as a unique solution. Einstein’s analysis includes “moving” clocks which show “stationary” time t, so the idea that a moving clock should run slower than a stationary clock is incompatible with his theory. Also, his calculation of time dilation contains serious errors. As a result, he fails to provide a theoretical justification for his famous “clocks paradox.” [ABSTRACT FROM AUTHOR]

The theory of special relativity is one of the most significant achievements in modern physics, with several important predictions such as time dilation, size contraction for a moving object, and mass-energy equivalence. Recent studies have demonstrated size contraction for an antiferromagnetic (AFM) domain wall (DW). Here, we show the excitation of terahertz (THz) magnons from a moving AFM DW under the magnetic anisotropy energy gradient. The energy of magnons comes from the loss of the effective DW mass due to the reduction in anisotropy energy. Also, the excitation of THz magnons is accompanied by a DW width broadening, overcoming the Lorentz contraction effect. Our results pave the way to study relativistic physics in AFM textures and to efficiently generate THz magnons by DC electric means. [ABSTRACT FROM AUTHOR]

This article is devoted to the criticism of the wave-particle dualism and the provisions of the special theory of relativity (SRT). The fallacy of accepting the extended principle of relativity and identifying particles and waves is shown. The substantiation is given that the own fields of physical objects, which are material substances and spatially connect physical objects with each other, are the medium of propagation of light waves. The causal and visual picture of the propagation of light waves is considered, and the features of the mechanism of their propagation in comparison with other types of waves are described. On the basis of an alternative method for obtaining the relativistic law of velocities addition, the inconsistency of the principle of invariance of the interval adopted in the framework of SRT is shown. The inconsistency of the SRT positions and conclusions regarding the so-called relativistic effects-time dilation, mass increase, length decrease, as well as the energy of relativistic particles is shown. The presence of the clock paradox is shown by a simple example. The conclusion is made about the incorrectness of using mathematical transformations of Lorentz and the four-dimensional continuum in the physical representation. [ABSTRACT FROM AUTHOR]

The importance of synchronization of spatially separated clocks in observing event coordinates cannot be overemphasized. We illustrate this with a real-world example. The results show the dependence of both length contraction and time dilation on the adopted synchronization convention. It is illustrated that a change in synchronization convention completely alters the appearance of the physical world. This is to be viewed in the context of the stated position in physics that synchronization of spatially separated clocks in any inertial frame depended on the adoption of a convention for its resolution. The preferred method of synchronization of spatially separated clocks is the standard convention recommended by the theory of relativity; however, it still remains a convention. [ABSTRACT FROM AUTHOR]

The rates of chemical reactions are not absolute but their magnitude depends upon the relative speeds of the moving observers. This has been proved by unifying basic theories of chemical kinetics, which are transition state theory, collision theory, RRKM and Marcus theory, with the special theory of relativity. Boltzmann constant and energy spacing between permitted quantum levels of molecules are quantum mechanically proved to be Lorentz variant. The relativistic statistical thermodynamics has been developed to explain quasi-equilibrium existing between reactants and activated complex. The newly formulated Lorentz transformation of the rate constant from Arrhenius equation, of the collision frequency and of the Eyring and Marcus equations renders the rate of reaction to be Lorentz variant. For a moving observer moving at fractions of the speed of light along the reaction coordinate, the transition state possess less kinetic energy to sweep translation over it. This results in the slower transformation of reactants into products and in a stretched time frame for the chemical reaction to complete. Lorentz transformation of the half-life equation explains time dilation of the half-life period of chemical reactions and proves special theory of relativity and presents theory in accord with each other. To demonstrate the effectiveness of the present theory, the enzymatic reaction of methylamine dehydrogenase and radioactive disintegration of Astatine into Bismuth are considered as numerical examples. [ABSTRACT FROM AUTHOR]

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In this paper, it has been shown that some experimental confirmations for the so-called "time dilation effect" may be in a rational way explained on the basis of a thought experiment presented in a previous paper [J. Drozdzynski, Phys. Essays 26, 321 (2013)]. The performed analysis has proven, that in order to carry out a round trip of a laser pulse from the source to a perpendicular located mirror and back to the starting point, the laser source in motion of the spaceship with a constant speed must be pointed at an angle in the direction of movement; whereas at rest it should be directed perpendicular to that axis. This means, that we have not to deal with a "time dilation effect" but with two separate measurements of two separate laser signals, moving at two different distances. The ratio of the two time intervals is expressed by a somewhat different equation as stated by the Special Theory Relativity and possesses also a dissimilar meaning. It has been shown also that it can be evaluated by the observer in motion by himself as well as that the phenomenon of a reiativistic length contraction does not exist. On this basis, a quantitative relation between time intervals of such oscillations in two reference frames, which are in motion with a different speed with respect to the frame at absolute rest, has been received. The relation may be of some significance for the Global Positioning System (GPS). A rational explanation of the "moving clocks" experiments as well as the "time dilation effect" of muons is presented. The existence of "paradoxes," resulting from Special Relativity has been excluded. A new elucidation of the null result in the Michelson-Morley experiment is presented. The analysis was based on classical physics and is giving additional evidence for the erroneousness of the principle of relativity. [ABSTRACT FROM AUTHOR]

Introduce a standard Euclidean geometric model with a maximum speed c, which may help us understand why the speed of light c is the universe's maximum speed, why parameter c is a constant, and the geometric mechanism that causes time dilation and length contraction. Finally, based on this model, this paper will present a new coordinate transformation and general velocity addition formula. The new general velocity addition formula is not only consistent with the Michelson-Morley experiment but also consistent with the one-way speed of light experiment and the linear Sagnac experiment. [ABSTRACT FROM AUTHOR]

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The light clock thought experiment can be shown to yield time contraction results. Consequently, two synchronous light clocks placed inside a space ship in uniform motion can simultaneously yield, from another frame, dilation and contraction of time, respectively. Based on these absurd results, we conclude that time dilation is not real or, at least, the light clock thought experiment cannot be used to infer time dilation. [ABSTRACT FROM AUTHOR]

The speed of light is observed differently depending on the observer's velocity. Therefore, the Lorentz contraction cannot be derived; the length contraction is unnecessary in physics. Time dilation has been experimentally confirmed. Using Einstein and Feynman light clock, we show that the Lorentz time dilation is derived in Fresnel's ether. The Galilean transformation with Lorentz time dilation is introduced. [ABSTRACT FROM AUTHOR]

The Sagnac effect and related twin paradox with a rotating disc are analyzed. It may seem that the special theory of relativity gives an easy and exhaustive treatment here. However, such consideration is deceptive since the principles of special relativity are originally established only for the inertial frames of reference, whereas the Sagnac experiment and the twin paradox exist in a noninertial one. We introduce an additional group of motions related to the rotation with uniform angular speed and show that these transformations leave the Minkowski metric invariant. Thus, we can give a firm mathematical ground to a usual easy consideration of the Sagnac effect. It should be noted that the presented result is true for a special case of motions; general coordinate transformations into accelerating frames of reference do not preserve the metric. [ABSTRACT FROM AUTHOR]

It has long been suspected by general relativists that physicists who do not specialize in general relativity (GR) believe that special relativity (SR) is incapable of modeling dynamics within accelerated reference frames. Consequently, many physicists may conclude that certain phenomena, such as time dilation due to acceleration, can only be described with GR. The fact of the matter is, as long as spacetime is flat, SR is fully capable of describing the dynamics of accelerated reference frames. In the classic textbook Gravitation, the authors state that "special relativity was developed precisely to predict the physics of accelerated objects." To quote Sean Carroll in his textbook Spacetime and Geometry, "The notion of acceleration in special relativity has a bad reputation, for no good reason." Finally, in a quote that drives the main point of this article home, the late general relativist Alfred Schild once said, "A good many believe that [the twin] paradox can only be resolved by the general theory of relativity. They find great comfort in this because they don't know any general relativity." [ABSTRACT FROM AUTHOR]

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The general theory of relativity extends the special theory of relativity to account for gravity (acceleration) and results in the postulation that matter curves spacetime, where gravitation is the embodiment of the spacetime curvature. The curvature of spacetime is modeled using Riemannian geometry. In this paper, it is proposed that matter rotates spacetime hyperbolically, rather than curves spacetime. As a result, gravitation is the embodiment of the hyperbolic rotation of spacetime. Regions in spacetime that have a larger magnitude of rotation relative to other regions of spacetime, ceteris paribus, experience stronger gravity, gravitational time dilation, gravitational length contraction, and gravitational frequency shift toward the red (blue) in the electromagnetic waves moving away (toward). [ABSTRACT FROM AUTHOR]

Two different forms of time dilation, namely, the kinematical time dilation of special relativity and gravitational red shift are coupled together during observations of a system travelling through a gravitational field. In the case of a Schwarzschild geometry these two effects are decoupled and in consequence they factorise. Such a factorization is not a universal feature. We define here a necessary and sufficient criterion for time dilation and gravitational red-shift decoupling. This property is manifested in a particular form of the frequency shift in a Schwarzschild geometry. [ABSTRACT FROM AUTHOR]

According to the special theory of relativity (STR), when the velocity of a moving body increases, the length of the body contracts in the direction of motion, and the passage of time slows down in its coordinate system. This conclusion can be derived from the equations of the Lorentz transformation. Inside the atom, however, potential energy must be taken into account, and the equations of the Lorentz transformation cannot be applied. In situations where the transformation equations newly derived by the author can be applied, if the velocity of a moving body increases, then the body elongates in the direction of motion, and the passage of time speeds up in its coordinate system. At the same time, the relativistic energy and mass of the body decrease. In the special theory of relativity, it is the relative velocity between the stationary frame and moving frame which determines length in the direction of motion of the moving body, and the tempo of the time which passes in the body's coordinate system. However, this paper rejects the claim that relativistic velocity is the factor which determines the body's length and the time which passes. Instead it concludes that the true cause is the ratio of the body's rest mass energy and relativistic energy--a ratio which varies as the velocity of the moving body increases and decreases. [ABSTRACT FROM AUTHOR]

A review of experimental tests of time dilation in special relativity is given, with an emphasis on the recent heavy-ion storage-ring work, currently the most sensitive method. The experimental results are evaluated in the context of the kinematic test theories of Robertson and Mansouri and Sexl, which assume the existence of a preferred inertial reference frame. Prospects for future improvements and the sensitivity of time dilation experiments to Lorentz and CPT violating extensions of the standard model are discussed. [ABSTRACT FROM AUTHOR]

One of the biggest unsolved problems in physics is explaining what time is. The paper explains what time is in kinematics theories. It has been proved that in the kinematics of Special Theory of Relativity (STR) and Special Theory of Ether (STE) time is measured by the light clock. Therefore, all properties of time in kinematics result from the properties of a signal clock. The paper explains the time dilation phenomenon on the basis of STE. The presented explanation is not only a classic description of time dilation but is based on the construction of an innovative technical model of this phenomenon. Time dilation is due to the properties of the light clock. It is a natural property of this clock. The article shows that the claim that the speed of light in a vacuum is the maximum speed in the real world has no theoretical basis. In modern physics, such a doctrine has been adopted as a result of an overinterpretation of the mathematics on which the Special Theory of Relativity is based. The presented model shows how, using atomic clocks, it may be possible to determine the movement in relation to the universal frame of reference in which electromagnetic signals propagate. This article contains only original research. [ABSTRACT FROM AUTHOR]

Teaching special relativity to lower-division students is challenging because results such as time dilation, length contraction, and frame dependence of simultaneity are counterintuitive. The literature is extensive, so only a brief list is given here, with articles divided roughly between discussions of general principles and calculations applied to selected physical systems. [ABSTRACT FROM AUTHOR]

We examine the Lorentz factor and the Schwarzschild solution in relation to the estimation and verification of time dilation in particular from Global Positioning System data. As a result, we detect the possible occurrence of a proportionality between the time dilation effects of special and general relativity in free-fall motion in Keplerian orbits. This observation is then proved mathematically. The results show that gravitational time dilation during free fall in Keplerian orbits must be exactly double that caused in special relativity due to linear velocity. We propose that a law be enunciated in view of the proof provided, and of the experimental and technological verification of time dilation effects during the past six to seven decades. The importance of this finding as a universal phenomenon and in the further development of stable clocks and satellite technology is highlighted. [ABSTRACT FROM AUTHOR]

Time dilation is one of the most fascinating aspects of special relativity as it abolishes the notion of absolute time. It was first observed experimentally by Ives and Stilwell in 1938 using the Doppler effect. Here we report on a method, based on fast optical atomic clocks with large, but different Lorentz boosts, that tests relativistic time dilation with unprecedented precision. The approach combines ion storage and cooling with optical frequency counting using a frequency comb. 7Li+ ions are prepared at 6.4% and 3.0% of the speed of light in a storage ring, and their time is read with an accuracy of 2×10−10 using laser saturation spectroscopy. The comparison of the Doppler shifts yields a time dilation measurement represented by a Mansouri–Sexl parameter , consistent with special relativity. This constrains the existence of a preferred cosmological reference frame and CPT- and Lorentz-violating ‘new’ physics beyond the standard model. [ABSTRACT FROM AUTHOR]

The Theory of Relativity, in both the Special and General cases, possesses profound inferences concerning the nature of time as a physical component of universal structure, and not as either an abstract concept or a universal entropic progression as is commonly perceived. While the time-slowing observations of what is known as Relativistic "time dilation" are well documented, the temporal interpretations of such dilation effects were critically affected by a Newtonian view of universally invariant time. Consequently, the most sophisticated interpretations of time dilation were parasitically molded by archaic views of physical time and have remained essentially unchallenged for a century, inhibiting any attempts to functionally integrate the observations of Relativity with Newtonian Mechanics. By freeing relativistic observations from the limited paradigm of Newtonian temporal concepts, an alternative, robust interpretation of Special Relativity, one acting in concert with the actions of bodies as described by Newtonian Mechanics, is produced and discussed. [ABSTRACT FROM AUTHOR]

The case of two rockets approaching each other with constant velocity is used to underscore a common misconception in relativity theory. Since each rocket is an inertial system (IS), it has been argued that a clock located on either one of them must be running faster in each case than an identical clock on the other (symmetry principle). This conclusion is based on the Lorentz transformation (LT) of Einstein's special theory of relativity (STR). There has never been an experimental verification of this prediction, however. On the contrary, experiments with atomic clocks carried onboard airplanes and rockets have demonstrated that their rates can be computed in a simple manner just by knowing their speed relative to the Earth's non-rotating polar axis. After accounting for gravitational effects, it has always been found that the rates of these clocks are slower than those of identical counterparts located on the polar axis. These results can be predicted quantitatively by defining an objective rest system (ORS), the Earth's polar axis in the present case, from which to uniquely apply Einstein's time dilation formula for clocks moving relative to it. On this basis it is concluded that measurement is objective (rational) rather than symmetric, and that the LT therefore does not correctly predict the rates of atomic clocks on a sufficiently general basis. A key result of the ORS formulation is that the lifetime of meta-stable particles on the Earth's surface measured by an observer moving at high speed relative to them is shorter than the value he finds for the identical particles when they are at rest in his laboratory. More generally, this approach underscores the advantages of introducing a set of physical units that is dependent on the state of motion of the observer. [ABSTRACT FROM AUTHOR]

The article discusses about simplifying time dilation and length contraction to students through a thought experiment. Topics include the Lorentz transformations; experiments conducted using a light clock, the period of oscillation of the photons, and explaining the students about special relativity.

Special relativity is a half-baked theory in which Lorentz transformation only considers the outbound or departing motion where speed and distance change in the same direction. This paper considers the inbound or approaching motion where speed and distance change in the opposite direction. This paper derived a new form of transformation along with the new Lorentz factor, according to which, in addition to well-known time dilation caused by outbound motion, there would be time contraction caused by inbound motion. [ABSTRACT FROM AUTHOR]

This experiment examined the effect of a train of regular repetitive clicks of different frequencies (8 Hz, 20 Hz) on time judgment in a bisection task in children aged 5 and 8 years old and adults with two duration ranges (200/800 and 400/1600 ms). Participants’ scores on neurospychological tests assessing memory, information processing speed and different components of attention control were also measured. The results showed that a train of clicks produced a time dilation in the children as well as in the adults, with the result that the perceived duration was judged to last longer with than without clicks. However, the time dilation reached a maximum level at a lower click frequency value (8 Hz) in the children than in the adults (20 Hz). In addition, beyond this click value (8 Hz), a reversal effect was observed in the youngest children, who responded “long” less often, while the time dilation was extended in the adults. In addition, while the differences in the time dilation between the click and the no-click condition were not correlated with the individual cognitive capacities, those that occurred when the click frequency increased from 8 to 20 Hz were significantly correlated with individual capacities in terms of attention and working memory. The hypothesis of a slower internal clock in the younger children is discussed as are the attentional interference processes involved in the click effect on time judgment. [ABSTRACT FROM AUTHOR]

Reflected laser light spots on distant targets were observed for 24 h periods by two separate laboratories. Although claims made in one study suggested this was not the case, in fact both data sets indicate no sufficiently significant shift of the centers of the reflected spots on the targets as the earth orbited and revolved during the measurements. This means that photons from the laser sources also travel lateral with the earth and targets so as not to shift the target arrival spot. This demonstrates the phenomenon termed synchronous aberration. The fact that photons do not follow the linear line along the ground between source and target but rather follow a diagonal, from the source at an original position to the target at a later shifted position, means that a stationary outside observer, but not an observer moving with the system, could be aware of the distance traveled to compute time for the event. Time dilation due to motion in special relativity theory is thus disproven, where a moving observer would merely use the ground distance between source and target to compute time incorrectly. Time for a light event is not dependent on motion of an observer that does not control the event, but may be incorrectly computed by an observer in motion. Physics texts must be corrected to avoid this long-held misconception in the future. [ABSTRACT FROM AUTHOR]

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Deformed relativistic kinematics is a framework which captures effects, that are expected from particles and fields propagating on a quantum spacetime, effectively. They are formulated in terms of a modified dispersion relation and a modified momentum conservation equation. In this work we use Finsler geometry to formulate deformed relativistic kinematics in terms of particle velocities. The relation between the Finsler geometric velocity dependent formulation and the original momentum dependent formulation allows us to construct deformed Lorentz transformations between arbitrary frames. Moreover, we find the corresponding compatible momentum conservation equation to first order in the Planck scale deformation of special relativity based on the κ-Poincaré algebra in the bicrossproduct basis. We find that the deformed Lorentz transformations, as well as the deformed time dilation factor, contain terms that scale with the energy of the particle under consideration to the fourth power. We derive how the distributions of decay products are affected when the deformed relativity principle is satisfied and find, for the case of a pion decaying into a neutrino and a muon, that the ratio of expected neutrinos to muons with a certain energy is just slightly modified when compared to the predictions based on special relativity. We also discuss the phenomenological consequences of this framework for cosmic-ray showers in the atmosphere. [ABSTRACT FROM AUTHOR]

There are two factors responsible for the relativistic Doppler effect. One of these contributions is of first-order in the velocity of the light source relative to the observer and is nonrelativistic in nature, but there is also a second-order (transverse Doppler) effect caused by the difference in rates of clocks at the source and in the laboratory (time dilation). It is pointed out that the traditional derivation for the relativistic Doppler effect based on the assumed Lorentz invariance of the phase of light waves is too restrictive. According to the latter argument, when two observers in relative motion send out signals to one another employing an identical light source, their respective measured Doppler shifts should always be the same (totally symmetric). However, an alternative derivation can also be given which indicates that the second-order contribution should in fact be anti-symmetric, although this analysis agrees with the conclusion that the corresponding first-order Doppler effect is symmetric. This is because there is a reciprocal relation between the ratios of the rates of the moving and rest clocks for the two observers. Quantitative calculations of the amount of the predicted anti-symmetry in transverse Doppler shifts are made for several examples on the basis of experimental data reported for the rates of atomic clocks carried onboard airplanes and rockets. Because of the Earth's rotation about its polar axis, the Doppler shifts can be measured in principle by using exclusively land-based atomic clocks located at widely different latitudes. Verification that the transverse Doppler frequency shifts are indeed antisymmetric would be a definitive confirmation that the oftcited symmetry principle of Einstein's special theory of relativity (STR) is incorrect, namely the claim that two observers in relative motion should each find that his/her clocks run faster than the other's. Finally, changes in the formulation of relativity theory that bring it into agreement with modern-day observations of variations in the rates of clocks with state of motion are discussed with reference to the methodology of the Global Positioning System (GPS). [ABSTRACT FROM AUTHOR]

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article discusses the topic of interstellar travel and its challenges. It highlights the common misconception that distances between celestial objects are much larger than the objects themselves. The article also explores the concept of relativity and its potential implications for space travel. It presents a mathematical equation that can be used to calculate ship time for long journeys, taking into account the effects of acceleration and time dilation. The article concludes by acknowledging the various practical and human factors that would need to be considered for extended space travel. [Extracted from the article]

Captain Einstein is a virtual reality (VR) movie that takes you on a boat trip in a world with a slow speed of light. This allows for a direct experience of the theory of special relativity, much in the same spirit as in the Mr. Tompkins adventure by George Gamow (1939). In this paper, we go through the different relativistic effects (e.g., length contraction, time dilation, Doppler shift, light aberration) that show up during the boat trip, and we explain how these effects were implemented in the 360 ° video production process. We also provide exercise questions that can be used-in combination with the VR movie-to gain insight and sharpen the intuition on the basic concepts of special relativity. [ABSTRACT FROM AUTHOR]

In this paper, Lorentz-type coordinates' transformations are proposed to connect the coordinates of an accelerating reference frame with the coordinates of a fixed one. Next, these transformations are applied to accelerating frames of constant acceleration. Finally, the Lorentz-type transformations are applied to the twin paradox, in an attempt to describe how the acceleration affects this phenomenon. [ABSTRACT FROM AUTHOR]

The theory of special and general relativity causes a "schizophrenic" dilemma in physics. It undeniably provides mathematically correct values, but it is undeniably epistemologically wrong in many respects. Including the relativistic explanation of the gravitational "time dilation" and the curvature of light beams at the surfaces of large masses, the author demonstrates the illogical character of relativistic physics. When one thinks the relativistic explanations of gravitational time dilatation and of the curvature of light rays by masses through to the end, they lead to absurd and contradictory logical conclusions. [ABSTRACT FROM AUTHOR]

We exemplify the role of acceleration in the twin paradox by calculating explicitly the elapsed proper time of each twin, according to each twin. In the limit that the coasting periods are much longer than the accelerating periods for the travelling twin, we find that the accelerating portions of the trajectory is crucial for the calculation of the elapsed proper time of the inertial twin according to the travelling twin, but irrelevant for all other calculations. We point out that the naive symmetry between the two twins is actually explicitly broken as soon as the turn around point is specified in the inertial twins reference frame. [ABSTRACT FROM AUTHOR]

The twin paradox has played an important role in the history of special relativity (SR). A precise calculation would require the application of the general theory of relativity (GR) but, neglecting the acceleration phases of the traveling twin, even in SR it is possible to find the correct solution without logical contradictions. Nowadays it is well known that the twin thought experiment seems a paradox as a consequence of a naive application of time dilation and the principle of relativity. The twin who goes on space travel is the one who, returning to the twin at rest, finds the aged brother. Continuing in this pedagogical tradition, we want to add a further consideration. In fact, the experiment has always been explained by considering the two twins immersed in Minkowski's spacetime. It could be interesting, from a didactic point of view, to analyze the same thought experiment without neglecting the Earth's gravitational field. Indeed, under certain conditions, it may happen that the traveling brother can grow older than his brother at rest. [ABSTRACT FROM AUTHOR]

We review how the kinematic structures of special relativity and quantum mechanics both stem from the relativity principle, i.e., "no preferred reference frame" (NPRF). Essentially, NPRF applied to the measurement of the speed of light c gives the light postulate and leads to the geometry of Minkowski space, while NPRF applied to the measurement of Planck's constant h gives "average-only" projection and leads to the denumerable-dimensional Hilbert space of quantum mechanics. These kinematic structures contain the counterintuitive aspects ("mysteries") of time dilation, length contraction, and quantum entanglement. In this essay, we extend the application of NPRF to the gravitational constant G and show that it leads to the "mystery" of the contextuality of mass in general relativity. Thus, we see an underlying coherence and integrity in modern physics via its "mysteries" and the fundamental constants c, h, and G. It is well known that Minkowski and Einstein were greatly influenced by David Hilbert in their development of special relativity and general relativity, respectively, but relating those theories to quantum mechanics via its non-Boolean Hilbert space kinematics is perhaps surprising. [ABSTRACT FROM AUTHOR]

What would the universe be like if we would give up the principle of equivalence and as a consequence incorporate gravity on a more traditional interaction basis within the theory of special relativity? The current work proposes such a gravitational model where a new law of gravitation is expressed in a Lorentz invariant form and is simultaneously in great agreement with many observations (including general relativity). We find the following predictions so far to be consistent with observations: (1) precession formulas explaining, for example, the Mercury apsidal precession, (2) gravitational bending of light near the limb of a massive object, (3) gravitational redshift, (4) escape velocity near a black hole, (5) several relativistic orbit details are derived in the strong field regime and found to be consistent with GR and also the observed shadow of the M87 black hole. Curved space effects such as gravitational time dilation or Shapiro delay cannot be explained within the realms of special relativity (Sect. 3.11). [ABSTRACT FROM AUTHOR]

This paper presents a fundamental and far-reaching criticism of the special theory of relativity. It aims to rescue the precious variable t from the artificial interpretation that Einstein gave it. Einstein defined a certain variable and called it time. I show that calling this variable time is extremely misleading. Instead I call it the Einstein clock variable, and I discuss the role of clocks in the scientific project of describing nature without using the word “time.” Einstein defines his clock variable as a fourth variable belonging to an inertial coordinate system. Each inertial coordinate system has its own instance of the Einstein clock variable, just as it has its own instances of three distance variables. A coordinate system’s instance of the Einstein clock variable is defined by a spatial array of indefinitely many clocks, all at rest relative to the object that anchors the coordinate system, and all coordinated with one another using a method that Einstein specifies. The key finding of this paper is that Einstein’s method of coordinating clocks results in a variable that has a nonzero spatial gradient. The value of the variable varies systematically with location, much as atmospheric pressure varies with altitude or the readings on clocks in airports around the world vary with time zone. All the sensational claims of the special theory of relativity, including the relativity of simultaneity, time dilation, length contraction, and the merging of space and time, use familiar words as redefined by Einstein to describe aspects of the relationship between two differently sloping instances of the Einstein clock variable. There is nothing in nature corresponding to any of these claims. The spatially sloping clock variable on which they are based is a thought-warping artifice that has no business in descriptions of nature. If physics is to be a natural science, this variable has no business in physics. [ABSTRACT FROM AUTHOR]