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George Gamow described In Mr. Tompkin in Wonderland a hypothetical world in which the speed of light is 10 km/h. Cyclists, who in such a world are obviously moved highly relativistically, are always seen by pedestrians as strongly contracted. Is this view always realistic?

I think It’s not always true: when the speed of a pedestrian is equal to the speed of a cyclist they don’t face the Length contraction anymore. Or am I wrong?

Tkt
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  • You are right, moving with the same speed in the same direction one would not see any length contraction, since the contraction depends only on the relative velocity – trula Feb 08 '23 at 11:05
  • That book is now only of historical interest. It does not show what it clams to show - what you see (no light beams ever enter anyone's eye). The possibility of misunderstanding what it says is approximately 100%. IMO it belongs in the archives with relativistic mass. Or in the fiction section alongside Lewis Carroll! – m4r35n357 Feb 08 '23 at 13:05
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    Same question from same OP (already closed) Length contraction. Wonderland – Quillo Feb 08 '23 at 13:27
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    @Tkt I edited your first post and voted to reopen it. In general, do not post duplicates. You may also be interested in this nice videogame "A Slower Speed of Light" developed at MIT is the payable analogue of Gamov's book http://gamelab.mit.edu/games/a-slower-speed-of-light/ gameplay: https://www.youtube.com/watch?v=hyj1ZZiseDE&ab_channel=ScottManley – Quillo Feb 08 '23 at 13:45
  • That program looked promising initially, but unfortunately is now abandoned. Far from being a "playable analogue" of Gamow, it takes a serious mathematical approach to what you would actually see (based on light beams entering the eye), including the doppler effect, aberration of light, and the "headlight effect". – m4r35n357 Feb 08 '23 at 15:19
  • @m4r35n357 it's kind of obvious that you can implement more math and all sort of effects in a videogame than on a page of a book for the general public written in 1939. The idea is the same, exactly a "slower speed of light", so you can see relativistic effects just walking around. – Quillo Feb 08 '23 at 16:02
  • @Quillo Sure. My point is that what you see in the game is nothing whatsoever like what you see(sic) in the book. To be clear to others, we do not "see" time dilation/length contraction directly as in Gamow, we see the effects I mentioned above. – m4r35n357 Feb 08 '23 at 17:57

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Exactly. A pedestrian running along the cyclist will see a normal cyclist and a flattened world.

Generally, the perspective of the world will warp as you move in this world: things will not just flatten, but seem to crowd in front of you as if seen through a fish-eye lens. But things moving with you will look normal.

Anders Sandberg
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