Propagation Speed of Gravity and the Relativistic Time Delay

2003 ◽  
Vol 590 (2) ◽  
pp. 683-690 ◽  
Author(s):  
Clifford M. Will
Keyword(s):  
Time Delay ◽  
Propagation Speed ◽  
Relativistic Time ◽  
Speed Of Gravity

scholarly journals COMMENTS ON "ON THE SPEED OF GRAVITY AND THE JUPITER/QUASAR MEASUREMENT" BY S. SAMUEL

2006 ◽  
Vol 15 (02) ◽  
pp. 273-288 ◽  
Author(s):  
SERGEI M. KOPEIKIN
Keyword(s):  
Time Delay ◽  
Review Article ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Speed Of Light ◽  
Propagation Of Light ◽  
Relativistic Time ◽  
Speed Of Gravity ◽  
General Relativistic ◽  
Recent Review Article

A recent review article by S. Samuel "On the Speed of Gravity and the Jupiter/Quasar Measurement" published as Int. J. Mod. Phys. D13, 1753 (2004), provides the reader with a misleading "theory" of the relativistic time delay in the general theory of relativity. Furthermore, it misquotes original publications by Kopeikin and Fomalont and Kopeikin related to the measurement of the speed of gravity by VLBI. We summarize the general relativistic principles of the Lorentz-invariant theory of the propagation of light in a time-dependent gravitational field, derive a Lorentz-invariant expression for the relativistic time delay, and finally explain why Samuel's "theory" is conceptually incorrect and confuses the speed of gravity with the speed of light.

scholarly journals Time-Delay Identification Using Multiscale Ordinal Quantifiers

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 969
Author(s):  
Miguel C. Soriano ◽  
Luciano Zunino
Keyword(s):  
Time Series ◽  
Time Delay ◽  
Real World ◽  
Propagation Speed ◽  
Real World Data ◽  
External Observer ◽  
The North ◽  
Weather Phenomenon ◽  
The North Atlantic Oscillation ◽  
Finite Propagation Speed

Time-delayed interactions naturally appear in a multitude of real-world systems due to the finite propagation speed of physical quantities. Often, the time scales of the interactions are unknown to an external observer and need to be inferred from time series of observed data. We explore, in this work, the properties of several ordinal-based quantifiers for the identification of time-delays from time series. To that end, we generate artificial time series of stochastic and deterministic time-delay models. We find that the presence of a nonlinearity in the generating model has consequences for the distribution of ordinal patterns and, consequently, on the delay-identification qualities of the quantifiers. Here, we put forward a novel ordinal-based quantifier that is particularly sensitive to nonlinearities in the generating model and compare it with previously-defined quantifiers. We conclude from our analysis on artificially generated data that the proper identification of the presence of a time-delay and its precise value from time series benefits from the complementary use of ordinal-based quantifiers and the standard autocorrelation function. We further validate these tools with a practical example on real-world data originating from the North Atlantic Oscillation weather phenomenon.

scholarly journals A proposal to measure the speed of gravity

2013 ◽  
Vol 91 (6) ◽  
pp. 455-455 ◽  
Author(s):  
M.B. Paranjape
Keyword(s):  
Gravitational Field ◽  
Time Delay ◽  
Finite Time ◽  
Simple Experiment ◽  
Speed Of Gravity ◽  
Moving Body ◽  
Two Bodies

We propose a simple experiment to measure the speed of gravity in the laboratory. A moving body induces changes in the gravitational field that travel to the detector with a finite time delay. Moving two bodies causes changes to the gravitational field. These changes can add or subtract, and observing this interference allows for the measurement of the speed of gravity.

A SHORT COMMENT ON THE JUPITER TIME-DELAY CONTROVERSIES

2006 ◽  
Vol 15 (02) ◽  
pp. 291-293
Author(s):  
S. CARLIP
Keyword(s):  
Time Delay ◽  
Speed Of Light ◽  
Light Passing ◽  
Speed Of Gravity ◽  
Considerable Controversy ◽  
Short Comment

The observation of Shapiro time delay of quasar light passing near Jupiter1 generated considerable excitement, but also considerable controversy. The disagreements involve two distinct issues: (i) Is there a vJ/c term in the time delay that is large enough to detect? (ii) If so, is the factor of c in the delay the "speed of gravity" cg or the "speed of light" c? I will comment briefly on each.

FOLD–HOPF BIFURCATIONS OF THE ROSE–HINDMARSH MODEL WITH TIME DELAY

2011 ◽  
Vol 21 (02) ◽  
pp. 437-452 ◽  
Author(s):  
SUQI MA ◽  
ZHAOSHENG FENG
Keyword(s):  
Time Delay ◽  
Center Manifold ◽  
Propagation Speed ◽  
Feedback Mechanism ◽  
Hopf Bifurcations ◽  
Neural Processing ◽  
Processing Information ◽  
The Stability ◽  
Finite Propagation Speed ◽  
The Rose

In neural processing information, when we consider the finite propagation speed of signals in synapses, a time delay signal self-feedback mechanism is introduced into the well-known Rose–Hindmarsh Model. The Fold–Hopf bifurcation of this model is analyzed near equilibria. To discuss the singularity of this Codim-2 bifurcation, we discuss the normal form near the Fold–Hopf points on the center manifold. Bifurcations are studied and the stability is investigated by classifying neighborhood regimes near the Fold–Hopf points. Finally, as one of the most important electrical behaviors in neurons, the complex bursting-spiking firing modes associated with bifurcations are illustrated by numerical simulations.

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