# On radar time and the twin “paradox”

@article{Dolby2001OnRT, title={On radar time and the twin “paradox”}, author={Carl E. Dolby and Stephen F. Gull}, journal={American Journal of Physics}, year={2001}, volume={69}, pages={1257-1261} }

In this paper we apply the concept of radar time (popularized by Bondi in his work on k calculus) to the well-known relativistic twin “paradox.” Radar time is used to define hypersurfaces of simultaneity for a class of traveling twins, from the “immediate turn-around” case, through the “gradual turn-around” case, to the “uniformly accelerating” case. We show that this definition of simultaneity is independent of choice of coordinates, and assigns a unique time to any event (with which the…

## 35 Citations

A note on Dolby and Gull on radar time and the twin “paradox”

- Physics
- 2005

Recently a suggestion was made that standard textbook representations of hypersurfaces of simultaneity for the traveling twin in the twin “paradox” are incorrect. This suggestion is false: The…

Notes on observational and radar coordinates for localized observers

- PhysicsPhysical Review D
- 2020

The worldline of a uniformly accelerated localized observer in Minkowski space is restricted in the Rindler wedge, where the observer can in principle arrange experiments repeatedly, and the Cauchy…

Noninertial Observers in Special Relativity and Clock Synchronization Debates

- Physics
- 2006

Selleri's arguments that a consideration of noninertial reference frames in the framework of special relativity identify “absolute simultaneity” as being “Nature's choice of synchronization” are…

A relativistic rotating frame with physics majors, photons and mirrors: causality lost

- Physics
- 2008

An analysis of cylinders rotating at relativistic speeds is considered from the point of view of observers living on the cylinders and from the point of view of observers in an inertial frame at rest…

Relativistic twins or sextuplets

- Physics
- 2003

A recent study of the relativistic twin 'paradox' by Soni in this journal affirmed that 'A simple solution of the twin paradox also shows anomalous behaviour of rigidly connected distant clocks' but…

Finding the Missing Time in the Instantaneous Turnaround Version of the Twin Paradox

- Physics
- 2006

The change in the reading on a distant Earth clock from the point of view of a traveling twin who instantaneously reverses direction is calculated by considering the behavior of the Earth clock…

A Light Clock Satisfying the Clock Hypothesis of Special Relativity.

- Physics
- 2007

The design of the FMEL, a floor-mirrored Einstein–Langevin 'light clock', is introduced. The clock provides a physically intuitive manner to calculate and visualize the time dilation effects for a…

Vibrating Rays Theory

- Physics
- 2014

The present work is aimed to explain why we started to consider Vibrating Rays Theory (VRT) as a viable representation of nature, and to elaborate some of its consequences. In 1846 Faraday introduced…

The relativistic rocket

- Physics
- 2009

We solve the problem of the relativistic rocket by making use of the relation between Lorentzian and Galilean velocities, as well as the laws of superposition of successive collinear Lorentz boosts…

The Minkowski metric in non-inertial observer radar coordinates

- Physics
- 2005

We give a closed expression for the Minkowski (1+1)-dimensional metric in the radar coordinates of an arbitrary non-inertial observer O in terms of O’s proper acceleration. Knowledge of the metric…

## References

SHOWING 1-10 OF 12 REFERENCES

Parallax distance, time, and the twin ’’paradox’’

- Physics
- 1981

An extension to all space‐time points of the definition of time and of distance for any observer, accelerating or not, by means of a parallax viewing of events is undertaken. The twin ’’paradox’’ is…

On the Electrodynamics of Moving Bodies

- Physics
- 1905

It is known that Maxwell's electrodynamics—as usually understood at the present time—when applied to moving bodies, leads to asymmetries which do not appear to be inherent in the phenomena. Take, for…

MÄRZKE-WHEELER COORDINATES FOR ACCELERATED OBSERVERS IN SPECIAL RELATIVITY

- Physics
- 2000

In special relativity, the definition of coordinate systems adapted to generic accelerated observers is a long-standing problem, which has found unequivocal solutions only for the simplest motions.…

The twin ‘‘paradox’’ and the conventionality of simultaneity

- Physics
- 1996

A new approach to understanding the twin paradox, based on the conventionality of simultaneity, is presented and illustrated. The canonical version of the twin paradox is discussed with reference to…

Assumption and myth in physical theory

- Physics, Philosophy
- 1967

Preface 1. The limits of theory making 2. Relativity: its myths and pre-suppositions 3. Gravitation 4. The origin of inertia and the universe Suggestions for further reading Index.

Introducing Einstein's Relativity

- Physics
- 1992

PART A: SPECIAL RELATIVITY PART B: THE FORMALISM OF TENSORS PART C: GENERAL RELATIVITY PART D: BLACK HOLES PART E: GRAVITATIONAL WAVES PART F: COSMOLOGY

Zur Elektrodynamik bewegter Körper

- Physics
- 1905

Este material fue digitalizado en el marco del proyecto subvencionado por la Fundacion Antorchas y se encuentra en la Biblioteca del Departamento de Fisica de la Facultad de Ciencias Exactas de la…

About time

- Nature
- 1996

Biochemical Oscillations and Cellular Rhythms: The Molecular Bases of Periodic and Chaotic Behaviour.By Albert Goldbeter. Cambridge University Press: 1996. Pp. 605. £70, $99.95.

Understanding Relativity: A Simplified Approach to Einstein's Theories

- 1996