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That groups of apparently faint GRBs are detected as having longer durations than groups of apparently bright GRBs is well known, and is sometimes referred to as “time dilation.” Reasons for GRB time‐dilation remain ambiguous, and likely convolve intrinsic effects, cosmological effects, and even detector threshold effects. With redshifts of a significant number of GRBs now in hand, attempts at an accurate deconvolution are now possible, and carry interesting cosmological implications. Toward this goal, we use redshift estimates of a large subset of BATSE GRBs obtained by Band et al. (2004) from the lag‐luminosity relation of Norris et al. (2000). Inspection of different sets of GRBs separated in estimated redshift appear to qualitatively show the expected time‐dilation effect, indicating that cosmological information was and is convolved in GRB BATSE data.

We measure time-dilation factors (TDFs) for 1158 long gamma-ray bursts (GRBs) using a peak-alignment method. Our standard corrections for noise bias and spectral redshift are implemented. Also for the first time we account for trigger bias against detecting relatively short, low signal-to-noise GRBs using a retriggering procedure which approximates the on-board BATSE algorithm on the 1024-ms timescale. This procedure implicitly addresses any bias that would be introduced when comparing bright bursts with dim bursts. The retriggering step significantly reduces the relative TDFs between the 10% brightest bursts and the 30% dimmest bursts. These corrected TDFs are compared with Monte Carlo simulations of a distribution of GRBs adopting standard cosmologies, GRB luminosity functions, and GRB rate-density evolution with cosmic time. Statistically, the corrected GRB TDFs are consistent with the expected extrinsic cosmological time dilation.

We present a means to assess the consistency of time dilation and energy shifting measurements with both the brightness distribution of BATSE and various Friedmann cosmological models. We utilize the methodology to assess the compatibility of a recent claim (1) of a time dilation factor of 2.25 from bursts separated by a factor of 21 in brightness. We show that these results are not compatible with the brightness distribution of BATSE, assuming a non-evolving population of standard-candle bursts embedded in an Einstein-de Sitter universe. Recent revisions of this value (2) downward to 1.75, which help to alleviate the discrepancy, however are still somewhat marginal in light of the energy-width corrections that need to be applied.

We perform several nonparametric correlation tests between brightness and duration of bursts in the BATSE 3B catalog to search for evidence of cosmological time dilation. These tests account for the effects of data truncation due to threshold effects in both limiting brightness and limiting duration, enabling us to utilize up to 46% of all triggered bursts in our analysis. Previous tests have been limited to ∼20% of all triggered bursts. We find no significant evidence for correlation between various measures of peak intensity and duration, but there is evidence for a positive correlation between fluence and duration, which is in the opposite sense of the correlation expected from time dilation.

The spatial distribution of bursts observed by BATSE is isotropic and inhomogeneous, implying that their sources may be at cosmological distances. We describe three tests that we have applied to search for the signature of time dilation. For both tests selection effects arising from intensity differences are avoided by rescaling all burst time profiles to a canonical dim peak intensity and rendering their backgrounds and noise biases uniform. These tests are (1) the distribution of pulse widths for these groups; a measure of the average rescaled integrated counts (2) within fitted pulse structures and (3) above fitted background for the burst ensembles. All tests use pulse shapes obtained from fitting major structures in temporal profiles. Results from 135 BATSE bursts indicate that the relative time dilation factor, dim to bright bursts, would be of order two, consistent with three previous tests, and with cosmological interpretations of the BATSE number‐intensity relation, all of which place the more di...

If gamma‐ray bursters are at cosmological distances ‐ a possibility suggested by their isotropic distribution and radial spatial inhomogeneity ‐ then the temporal profiles of more distant sources will be time dilated compared to those of relatively nearby sources. We apply two brightness‐independent tests for time dilation. Selection effects arising from intensity differences are removed by rescaling all bursts and associated noise levels to a canonical dim peak intensity. The first test measures the total normalized flux above background and indicates that dim bursts have approximately twice as much temporal structure as do bright bursts, suggesting that dim bursts are longer. Using wavelet transforms we show that, on average, dim bursts have significantly more structure than bright bursts on all time scales from 128 ms to 64 s.Simulations that approximate actual burst profiles indicate that time dilation should be detectable, given the observed distribution of burst durations and the assumption of a mod...

An Extended Abstract Theory of special and general relativity (SR and GR, respectively), received so much popularity and attention from the scientific media that a lot of papers in modern physics are devoted to it. One of the main constituents in the special relativity is a very known Lorentz Transformations (LT). There are many derivations of Lorentz Transformations (1-5). In all of the known derivations methods of the Lorentz Transformation model (LT-model), it is assumed that the observation signal is the light, which has the same (constant) speed in both observer and moving systems. So, one of the remaining questions is: are there possibilities to generalize LT-model in the sense of employing of a set of different observation signals including the light signal? It is expected that this generalization should contain both Lorentz-Einstein and Galilean Transformations, and could be helpful in a new unification of electromagnetic and gravitational fields. This paragraph was the basic motivation why this investigation started with a new general approach to derivation of Lorentz Transformations. This has been resulted with a new General Lorentz Transformation model (GLT-model), proposed in this paper. In Galilean space-time model the physical existence of an absolute time is assumed. The pioneer of physics Isaac Newton defined it in the reference (6). On the contrary, Minkowski space-time model does not know any absolute time which is physically meaningful. It was the revolutionary idea of Albert Einstein to give the notion of simultaneity a new definition. Especially, because all experimental tests to determine the motion with respect to some absolute space-time frame had failed, Einstein decided to abandon the notion of absolute time at all. It implies, in contrast to Galilean space-time model, that simultaneity is not an absolute physical quality, but a relative one, depending on the motion of the observer ( i.e. the reference frame). The applications of original Lorentz-Einstein Transformations properly expresses the apparent contraction of moving rods (Lorentz-Fitzgerald contraction) and the slowing of moving clocks (time dilation). This paragraph was the grate motivation for a second part of our investigation, where we consider the influences of GLT-model on the phenomena as a moving rods contraction (a length contraction), and a time dilation, as well as on an absolute time, and a relativistic time. Applying GLT-model, in this paper, the four new observation phenomena, called a length neutrality, a time neutrality, a length dilation and a time contraction have been discovered and considered. Contemporary physics states that no object should be travel faster than the speed of light. Although the speed of light appears to be enormous when compared with conventional travelling speeds, it suggests a limit which renders a practical realization of interstellar travel improbable. Whereas Galilean space-time model allows an observation of faster than light speeds, at least in principle, Minkowski space-time model does not. What is the reason for this difference ? In the reference (7), Schatzer exposed that the key point is the conception of global time, i.e. the physical significance of the term simultaneity. Although the one-way speed of light maybe is not constant in general (i.e. when expressed in an arbitrary reference frame), the mean-speed of light c of a round-trip is again constant (8,9). This is in accordance with all experiments, like Michelson-Morley experiment. It should be emphasized that there has been no experiment which determined the one-way speed of light (10), since this would require the possibility of synchronizing physical clocks by some other means than finite-speed signals. Thus, in fact, a certain experimental proof of the constancy of the one-way speed of light has not been given so far. This paragraph states the motivation for the third part of our investigation. In this part we consider the influences of GLT-model to limitations of the particle velocities, in relation to the possibility of observation of faster than light speeds, as well as the possibility of reduction of travel times. The success of the theory of relativity can be understood from the fact that the possibility to formulate all physical laws covariantly, appears most tempting (10, 11). However, there exists no covariant representation of the state reduction postulate (12). One example is the violation of the Bell inequalities (13), which has been confirmed experimentally (14, 15). Thus, quantum mechanics has proven to be correct (16). Although non-local effects are a constituent of quantum mechanics, most physicists still believe that faster signals than speed of light are impossible. It is because EPR-like effects (17), have not allowed to transmit information at superluminal speeds so far. Yet, EPR-correlations remain a mystery if local realism is assumed to be valid. Therefore, the possibility of superluminal communication has been acknowledged by various authors (18). In the reference (19) Cramer pointed out a quantum nonlocality and the possibility of superluminal effects, within a transactional interpretation of quantum mechanics and a non-linear quantum mechanics ( Weinberg, (20) ). Two years after Weinberg 's non-linear quantum mechanics was published, Polchinski presented that Weinberg' s non-linear corrections upset the balance in quantum mechanics that prevents superluminal communication using EPR experiments (21). Meanwhile, several tests indicated that any non-linearities in the quantum mechanics are extremely small, if they exist at all. Besides, it is well known that one can define a universal time, which appears in cosmological models as the cosmological time (22). Therefore, there exists no covariant 4-position operator in quantum mechanics. Since GLT-model contains both Lorentz-Einstein and Galilean space-time models (it means relativistic and absolute time approaches) this paragraph motivates for consideration of possibilities of an unification of the general relativity and the quantum mechanics approaches applying GLT-model. If it is possible at all, the first step must be a new unification of electromagnetic and gravitational fields. The preliminary investigation results indicate that GLT-model can help in this unification. Resent investigations of electromagnetic radiation propagating over cosmological distances seem to reveal a true anisotropy in the structure of our universe. It suggests that the speed of light might be not a true constant, but dependent on direction and polarization. These results might possibly represent a further indication in favour of the existence of an absolute reference frame (23). In the reference (24) Alcubierre presented that even within the frame work of general relativity faster than light speed is allowed, provided that the space-time metric of the universe is globally hyperbolic, and assuming that an exotic matter exists. The last two paragraphs suggest considerations of the possible ways (methods) for dynamic control of gravity or inertia in order to travel by faster than light speed, or at least close to this speed. This is the fourth objective of our investigation in this paper. As it is well known (25, 26) ideal interstellar drive would have ability to manipulate the connection between mass and space-time. One approach is to analyse the possibility of using of electromagnetism. It is known that electromagnetism and gravity are coupled phenomena, and we only need to recognize how to control inertial or gravitational forces. Although gravity's affects on electromagnetism have been confirmed (27, 28) , the possibility of using electromagnetism to affect gravity is unknown. Meanwhile, the resent investigations (29, 30) suggest that inertia is nothing but an electromagnetic illusion, and that gravity is nothing other than an electromagnetic side-effect. Following the previous paragraphs, a new general structure of Lorentz Transformations, in the form of General Lorentz Transformation model ( GLT-model ), has been derived. This structure includes both Lorentz-Einstein and Galilean Transformations as its particular ( special ) realizations. If GLT-model is correct then there are exist four new observation phenomena ( a length and time neutrality, and a length dilation and a time contraction ). Besides, the well known phenomena ( a length contraction, and a time dilation ) are also the constituents of GLT-model. It means that there is a symmetry in GLT-model, where the center of this symmetry is represented by a length and a time neutrality. An observation of the mentioned phenomena of GLT-model, in a particular case, depends on an observation signal velocity in both observer and moving systems, and on a velocity of a moving system relative to an observer system. A special consideration is devoted to a correlation between GLT-model and a limitation on particle velocities in order to investigate the possibility of a travel time reduction. The next goal is the investigation of influences of a time neutrality and a time contraction to the possibility of control of gravity or inertia. The previous investigation results give the hope that GLT-model can be helpful in investigation of the mentioned problems. We believe that for determination of influences between electromagnetism and gravity in both directions, one should make a new unification of electromagnetic and gravitational fields, using a new approach that includes properties of GLT-model. This unification should be done for multivariable gravitational field (two-body or n-body gravitational problems). Maybe this approach will help in the determination of the possibility of control of gravity or inertia. References (1) A. Einstein, " The collected papers of Albert Einstein", Vol. 2: The Swiss years: writings, 1900-1909 (Princeton, NJ, 1989. (2) A. Einstein, " The meaning of relativity " London, 1951. (3) A. I. Miller, " Albert Einstein's special theory of relativity : Emergence (1905) and early interpretation (1905-1911)", Reading, Mass., 1981. (4) I. Supek, " Theoretical physics and structure of matter", Skolska knjiga, Zagreb, (Cro), 1964, 1992. (5) M. A. Baig, " Derivation of Lorentz-Einstein Transforms and their impossibility at v!= 0", in http://www.eecs.uic.edu/nbutt/ , pp. 1-11, 1997. (6) I. Newton, " Mathematical principles of natural philosophy", Dawson, London, 1969. (7) L. Schatzer , " The speed of light - A limit on principle?", in http://monet. physik.unibas.ch/schatzer/space-time.html, pp. 1-10, October 1997. (8) J. P. Hsu, and L. Hsu, " A physical theory based solely on the first postulate of relativity", Physics Letters A 196, pp. 1-6, 1994. (9) F. Selleri, " Theories equivalent to special relativity", in Frontiers of Fundamental Physics, eds. M. Barone, and F. Selleri, Plenum Press, New York, 1994. (10) H. Reichenbach, " The philosophy of space and time", Dover, New York, 1958. (11) J. D. Jackson, " Classical electrodynamics", Wiley, New York, chapter 11, 1975. (12) Y. Aharonov, and D. Z. Albert, " Can we make sense of the measurement process in relativistic quantum mechanics ?", Physical Review D 24, pp. 359-370, 1981. (13) J. S. Bell, " On the Einstein Podolsky Rosen paradox", Physics 1, no. 3, p. 195, 1964. (14) A. Aspect et al., " Experimental realization of Einstein Podolsky Rosen Bohm gedankenexperiment : A new violation of Bell's inequalities", Physical Review Letters 49, no. 2, p. 91, 1982. (15) A. Aspect et al., " Experimental tests of Bell's inequalities using time-varying analyzers", Physical Review Letters 49, no. 25, p. 1804, 1982. (16) R. Y. Chiao, P. G. Kwiat, and A. M. Steinberg, " Faster than light ?", in Scientific American, August 1993. (17) A. Einstein, B. Podolsky, and N Rosen, " Can quantum-mechanical description of physical reality be considered complete?", Physical Review 47, p. 777, 1935. (18) O. Steinmann, " The EPR Bingo", Helv. Phys. Acta, vol. 69, pp. 702-705, 1996. (19) J. G. Cramer, " Quantum nonlocality and the possibility of superluminal effects ", in http://www.npl.washington.edu/npl/int_rep/qm_nl.html , pp 1-6, August, 1997. (20) S. Weinberg, " Non-linear QM theory ", Physical Review Letters 62, p.485, 1989. (21) J. Polchinsky , " Weinberg's non-linear corrections upset the balance in QM that prevents superluminal communication using EPR experiments ", Physical Review Letters 66, p.397, 1991. (22) S. Weinberg, " Gravitation and cosmology", Wiley, New York, chapter 14, 1972. (23) B. Nodland, and J. P. Ralston, " Indication of anisotropy in electromagnetic propagation over cosmological distances", Physical Review Letters 78, no. 16, pp. 3043-3046, 1997. (24) M. Alcubierre , " The warp drive : Hyper-fast travel within general relativity", Classical and Quantum Gravity 11, pp. L73-L77, 1994. (25) M. G. Millis, " Exploring the notion of space coupling propulsion ", in Vision 21: Space Travel for the Next Millennium, Symp. Proceedings, Apr. 1990, NASA-CP-10059, p. 307-316, 1990. (26) M. G. Millis , " Emerging possibilities for space propulsion breakthroughs " , http://www.lerc.nasa.gov/WWW/PAO/html/warp/ipspaper.htm, 1998. (27) R. Pool, " Closing in on Einstein's Special Theory of Relativity", in Science, Vol. 250, p. 1207-1208, Nov. 9, 1990. (28) C. W. Misner, K. S. Thorne, and J. A. Wheeler, " Gravitation " , W. H. Freeman and CO., New York, 1973. (29) B. Haisch, A. Rueda, and H. E. Puthoff," Inertia as a zero-point field Lorentz Force", in Physical Review A, Vol. 49, No. 2, p. 678-694, Feb. 1994. (30) H. E. Puthoff, " Gravity as a zero-point fluctuation force", in Physical Review A, Vol. 39, No. 5, (A89-33278), p. 2333-2342, Mar. 1, 1989.

In this paper, the local fifth force model developed by the author (Robertson, 2009) for a static mass density is extended to time varying mass densities. The time varying mass density model allows for field‐force effects due to the time variance of an object’s mass density and uses a concept know to electrical engineers as “Time Dilation and Retardation.” Time dilation and retardation (TDR) is used to describe the time delay effect on the ambient Chameleon field due to the changing of an object’s mass density. From this, hot‐gas rocket equations are developed from the integration of the local fifth force and the TDR equations.

Quantum theory limits what we are allowed to say about the “true” state of a quantum system if that system is unobserved. But special relativity relies fundamentally on a universal assumption about what a light particle is doing at ALL times, regardless of being observed (namely, traveling at speed c relative to any inertial observer). This constitutes a fundamental conceptual gap between the theories. In resolving this impasse we show that the state of a light particle (and hence space and time) is not objective or continuous. Time dilation and length contraction become infinite for a photon, so light has no “experience” of event separation in space or time (Δt′ = 0, Δx′ = 0). The principle of simultaneity is applied between an inertial observer and a light particle, such that the relative speed of the two systems is c, and gamma = infinite/undefined. Although light experiences no separation between events, the Lorentz transform Δt′ = γ (Δt−ΔLv/c2) implies that the inertial observer experiences a separat...

We present an analysis of the consistency of burst durations and spectra with a population of nonevolving sources at Gpc distances. The parameters T90 (T50) and Ep are calculated using data obtained with BATSE, and are used to characterize burst durations and spectra, respectively. Effects consistent with cosmological redshift and time dilation have been reported in the Ep and T90 data, respectively. We simultaneously examine the distributions of these parameters for cosmological time dilation and redshift effects, being careful to avoid the introduction of selection effects. We show that the T90 (T50) data are currently less constraining than Ep; the data do not require time dilation, but are consistent with the effect observed in the Ep data.

Alcubierre’s warp drive geometry seemingly represents the ultimate dream for interstellar travel: there is no speed limit, the passengers are weightless whatever the acceleration, and there is no time dilation. However, in its original form, the proposal suffers from several fatal flaws, such as unreasonably high energies, energy moving in a locally spacelike direction, and a violation of the energy conditions of classical Einstein gravity. I present a possible solution for one of these problems, and I suggest ways to at least soften the others.

In the Theory of Relativity time is treated as a dimension. This property of time has never been completely understood and accepted because we instinctively perceive time only as a running parameter. In recent developments of the Theory of Relativity, it has been proposed to apply a coordinate transformation by which the four coordinates all acquire the dimension of space, with time defined as a running parameter related to the speed of light. The transformation formally defines the Four‐Space or, using a common word for spaces with more than three dimensions, the “Hyperspace”. Under this paradigm, the entire story of the Universe is similar to a set of nested trajectories in which our “reality” develops along a membrane moving through the nested trajectories at the speed of light. The new paradigm implies the existence of multiple “parallel” membranes, or parallel local universes or multiverses and “crossing” membranes, or “orthogonal” local Universes, which do not emerge from the plain Theory of Relativity. In the Hyperspace everything normally travels at the speed of light, but a localized strong gravitational field, which creates a propagation speed discontinuity in Hyperspace, may allow travel to different local universes or Faster Than Light (FTL) travel within the same local universe. The collision or focusing of gravitational waves can produce effects comparable to those of short‐lived black holes that can be projected into the Hyperspace to produce the required speed modification. Well known optical effects and four‐dimensional rotation may also find application to Hyperspace travel.

We have measured T90 and T50 as a function of energy for a set of bright BATSE gamma-ray bursts, selected on the basis of their peak photon flux on the 64 ms time scale. These events lie mainly on the −3/2 portion of the log N(>P)–log P curve; thus, in the cosmological scenario their measured characteristics may be relatively free from redshift and time dilation effects, so that the measured dependence of duration on energy may reflect an intrinsic dependence. We examine the compatibility of our results with recent work (1), which showed that the functional dependence of duration on energy is well-represented by a power law.

If Gamma Ray Bursts are at cosmological distances, then the faint bursts must have light curves which are stretched in time when compared to bright bursts. Such a time dilation has been reported by Norris and coworkers, where the relative stretching of pulse durations is roughly a factor of two between bright and faint burst. Nevertheless, models have been presented which can account for this peak-duration dilation within galactic models. A solution to this ambiguity can be had by looking for dilation of different measures of time scale, as these would not be subject to the same effects. One such time scale is the peak-to-peak time. Cosmological models can only be true if the peak-to-peak dilation agrees exactly with the peak-duration dilation. This is a sharp test. In this paper, we report on our study of peak-to-peak dilation of 465 multipeaked bursts from the BATSE 2B catalog. We used a wide variety of peak selection criteria and peak-to-peak time scale definitions. We find that many tests can find dilations with a factor of two, yet that many other tests can prove that there is no dilation. That is, by selecting which test to adopt, we can make peak-to-peak dilation either appear or disappear at high levels of significance. We conclude that the measurement of dilation has subtle systematic errors of unknown nature, and these can only be recognized by detailed Monte Carlo analyses.

Many of the important conclusions about Gamma‐Ray Bursts follow from the distributions of peak flux or duration. We show that the triggering process for the bursts and possible correlation between these variables dictate that these distributions are related and can be obtained from a multivariate distribution. Using methods developed previously we extract the distributions of flux and duration from the BATSE 2B catalog. It is shown that properly accounting for the aforementioned biases tends to increase the slope of the log N‐log S relation at low values of peak flux S, and increases the number of short duration bursts. We find no obvious evidence for cosmological time dilation in the complete set.

We review the current status of experimental tests of general relativity, and describe future experiments in the LISA time frame that may improve the empirical underpinning of the theory.

In special relativity the chronogeometrical structure is absolute and there is no notion of instantaneous 3‐space: distant clock synchronization is based on a convention, which changes going from inertial to non‐inertial frames. On the contrary in Einstein general relativity the metric tensor has a double role: 1) it is the mediator of the gravitational interaction; 2) it determines the dynamical chronogeometrical structure of spacetime. As a consequence, it “teaches relativistic causality” to to every other field with the following implications: a) the conventions for distant clock synchronization in non‐inertial frames are dynamically determined; b) the 8 arbitrary gauge variables hidden in the metric tensor describe “inertial effects” in non‐inertial frames; c) the Dirac observables of the gravitational field describe “tidal effects” in non‐inertial frames. A Hamiltonian reading of Bergmann‐Komar intrinsic pseudo‐coordinates, in connection with Einstein’s Hole Argument, leads to a identification of the notions of “spacetime” and “gravitational field”, which must be taken into account in any approach to quantum gravity.

Four different concepts of “relative velocity” are given intrinsically in general relativity. The kinematic and kinematic2 relative velocities are defined in the framework of spacelike simultaneity, obtaining some general properties and interpretations. The kinematic relative velocity generalizes the usual concept of relative velocity when the two observers β, β′ are at the same event. On the other hand, the kinematic2 relative velocity does not generalize this concept, but it is physically interpreted as the variation of the relative position of β′ with respect to β along the world line of β. Analogously, the spectroscopic and astrometric relative velocities are defined and studied in the framework of observed (lightlike) simultaneity. Next, we give some relations between these concepts in special relativity. Finally, we show some fundamental examples in Schwarzschild and Robertson‐Walker space‐times.

One of the motivations behind numerical relativity is to provide gravitational wave signals of compact objects to observers using the new gravitational wave detectors. Yet, because of the complexities involved, no dependable signals of binary-black hole coalescences have been established. The work in this proceedings is motivated by how numerical relativity can be used today to predict robust features in gravitational wave signals of binary black-hole coalescence by making approximations to the full problem. To illustrate this, we present results from evolving a Klein-Gordon equation on a frozen background. The background is set by a sequence of initial data in which the binary is in quasi-equilibrium. We probe the data resulting from the evolution for the transition between the linear and non-linear regimes using oscillations of the black holes as our guide. This information is used to motivate a qualitative picture of the gravitational signal of a black-hole coalescence.