English
Related papers

Related papers: A tale of two twins

200 papers

Some recent experiments led to the claim that something can travel faster than light in vacuum. However, such results do not seem to place relativistic causality in jeopardy. Actually, it is possible to solve also the known causal…

High Energy Physics - Theory · Physics 2010-02-05 Erasmo Recami

Time dilation $\frac{1}{\sqrt{1-v^2}}$ and relative velocity $v$ are observationally indistinguishable in the special theory of relativity, a duality that carries over into the general theory under Fermi coordinates along a curve (in…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Hunter Monroe

We present the special theory of relativity taking the Doppler effect as the starting point, and derive several of its main effects, such as time dilation, length contraction, addition of velocities, and the mass-energy relation, and…

Classical Physics · Physics 2009-11-11 M. Moriconi

The special theory of relativity has fundamentally changed our views of space and time. The relativity of simultaneity in particular, and the theory of relativity as a whole, still presents significant difficulty for beginners in the…

Classical Physics · Physics 2022-10-27 Abdaljalel Alizzi , Abhijit Sen , Zurab K. Silagadze

In this letter, we give a simple and analytical solution to the twin paradox. It relies just on Lorentz transformations and does not involve accelerated frames or any kind of signals exchanged between the twins. We expect that with this we…

Popular Physics · Physics 2023-03-17 G. Alencar

A new apparent relativistic paradox is presented involving only one space-time event. This is different from earlier relativistic paradoxes involving extended bodies or events at different positions. A collision between a rod and a ring…

General Physics · Physics 2022-02-03 Oyvind Gron , Eirik Berntsen

We consider a new version of the twin paradox. The twins move along the same circular free photon path around the Schwarzschild center. In this case, despite their different velocities, all twins have the same non-zero acceleration. On the…

Astrophysics · Physics 2009-11-11 Marek A. Abramowicz , Stanislaw Bajtlik , Wlodek Kluzniak

In this work, the relativistic phenomena of Lorentz contraction and time dilation are derived using a modified distance formula appropriate for discrete space. This new distance formula is different than Pythagoras's theorem but converges…

General Relativity and Quantum Cosmology · Physics 2018-10-10 David Crouse , Joseph Skufca

The Einstein-Podolski-Rosen paradox highlights several strange properties of quantum mechanics including the super position of states, the non locality and its limitation to determine an experiment only statistically. Here, this well known…

Quantum Physics · Physics 2017-09-13 Roland Riek

The phase of matter waves depends on proper time and is therefore susceptible to special-relativistic (kinematic) and gravitational (redshift) time dilation. Hence, it is conceivable that atom interferometers measure general-relativistic…

A fifty-year old apparently paradoxical thought experiment involving two accelerating spaceships and a thread hat connects them states that the thread will break due to length contraction. This paradox still appears to be regarded by some…

Classical Physics · Physics 2009-03-31 Vesselin Petkov

An orbiting `photon clock' is proposed to test directly the relativity of simultaneity of special relativity. This is done by comparison of the arrival times at a ground station of three microwave signals transmitted by two satellites…

General Physics · Physics 2007-05-23 J. H. Field

When faced with overwhelming evidence supporting the reality of time dilation, confirmed in particular by the Hafele-Keating experiment, some anti-relativists reluctantly concede that time dilation applies to light clocks. However, they…

Popular Physics · Physics 2025-07-23 Val G. Rousseau

This manuscript presents a problem on special relativity theory (SRT) which embodies an apparent paradox relying on the concept of simultaneity. The problem is represented in the framework of Greek epic poetry and structured in a didactic…

History and Philosophy of Physics · Physics 2013-10-25 Fabrice Leardini

We define the time travel paradox in physical terms and prove its existence by constructing an explicit example. We argue further that in theories -- such as general relativity -- where the spacetime geometry is subject to nothing but…

General Relativity and Quantum Cosmology · Physics 2009-11-07 S. Krasnikov

It is hypothesized that the Langevin time of stochastic quantum quantization is a physical time over which quantum fields at all values of space and coordinate time fluctuate. The average over paths becomes a time average as opposed to an…

Quantum Physics · Physics 2017-08-16 Michael Grady

An orbiting `photon clock' is proposed to test directly the relativity of simultaneity effect of special relativity. This is done by exchanging microwave signals between two satellites in low Earth orbit carrying clocks that have previously…

General Physics · Physics 2011-06-06 J. H. Field

In Einstein's Special Theory of Relativity, all observers measure the speed of light, $c$, to be the same. However, this refers to the round trip speed, where a clock at the origin times the outward and return trip of light reflecting off a…

General Relativity and Quantum Cosmology · Physics 2021-02-17 Geraint F. Lewis , Luke A. Barnes

Motivated by a conjecture put forward by Abramowicz and Bajtlik we reconsider the twin paradox in static spacetimes. According to a well known theorem in Lorentzian geometry the longest timelike worldline between two given points is the…

General Relativity and Quantum Cosmology · Physics 2012-04-11 Leszek M. Sokolowski

We deal with a problem concerning a supposed inconsistency in the special relativistic treatment of the so-called linear Sagnac effect. It is shown that, under modern clothes, the root of the difficulty perceived by some authors lies in…

General Relativity and Quantum Cosmology · Physics 2025-12-09 Marco Mamone-Capria