Any research about real measurements with objects moving faster than me - like GPS, for example - leads to a mix of different sideway phenomenons like different gravitational potentials on Earth and in orbit or accelerations during liftoff and landing. I'm curious; was Einstein had able to answer this thought experiment?

According to Wikipedia,

Langevin solved the paradox by alluding to the fact that one twin accelerates and changes direction

, so perhaps it is more precise to ask about when the twin paradox was simplified to "a travelling twin and a twin in rest". Perhaps the question more specific has to be: When the simplification of the twin thought experiment to the twin paradox took place? When did this happens?

  • $\begingroup$ Somehow this question I got after reading How do I know which observer is running the time faster or slower? $\endgroup$ Feb 4, 2016 at 17:37
  • $\begingroup$ @march See the comment. BTW, your vita is interesting, could you comment my elaboration About the distribution of electrons magnetic dipole moments in atoms? Perhaps condensed matter has something to do with magnetic dipole moments? $\endgroup$ Feb 4, 2016 at 17:47
  • $\begingroup$ @HolgerFiedler. Possibly (I'm not at all an expert on anything related to magnetism), but I'd prefer not to have to sign up for that service in order to download the paper! $\endgroup$
    – march
    Feb 4, 2016 at 17:51
  • $\begingroup$ @march oh, I was not aware that a reader has to registers too. How to upload it for you? $\endgroup$ Feb 4, 2016 at 17:53
  • $\begingroup$ I forgot to delete it. In fact, there is another twin joke in this old story, but it is not relevant for the format. Really sorry $\endgroup$
    – igael
    Feb 4, 2016 at 17:54

1 Answer 1


The alluded to Wikipedia has a rather well referenced article on Twin paradox specifically. Einstein himself formulated the "paradox" in terms of clocks already back in 1905. He considered it just "peculiar" however rather than a paradox, because it led to no contradictions that needed to be resolved.

In 1911 Einstein replaced clocks with living organisms, perhaps to make the peculiarity more striking:"If we placed a living organism in a box... one could arrange that the organism, after any arbitrary lengthy flight, could be returned to its original spot in a scarcely altered condition, while corresponding organisms which had remained in their original positions had already long since given way to new generations". The same year Langevin replaced organisms with human travelers, and von Laue turned them into twins.


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