Timeline for How do we explain this new take on the old Twins Paradox? [closed]
Current License: CC BY-SA 4.0
29 events
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| Sep 26, 2018 at 19:20 | review | Reopen votes | |||
| Sep 27, 2018 at 4:42 | |||||
| Sep 26, 2018 at 19:04 | history | edited | Stuart Van Horne | CC BY-SA 4.0 |
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| Sep 26, 2018 at 18:42 | history | edited | Stuart Van Horne |
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| Sep 26, 2018 at 9:44 | comment | added | Sean | So I guess the question is, how does one form of acceleration create a constantly changing reduction of the rate of the passage of time (Linear), yet the other form of acceleration does not (Centrifugal). | |
| Sep 24, 2018 at 13:06 | history | closed |
WillO John Rennie Kyle Kanos ZeroTheHero user191954 |
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| Sep 23, 2018 at 22:54 | answer | added | user93146 | timeline score: 2 | |
| Sep 23, 2018 at 22:43 | comment | added | WillO | @stuartvanhorne: all I am saying is that anyone who reads and digests any of the easily available posts resolving the twin paradox will see that spinning has as little to do with the resolution as the twins' names do, and that therefore this question should be treated just as we would treat a question that put a "new twist" on the problem by changing their names. That is 100% of what I am saying. | |
| Sep 23, 2018 at 21:45 | comment | added | Stuart Van Horne | @WillO, so acceleration never causes time-dilation in and of itself (putting aside gravitational time-dilation), but it does cause a change of reference frames, which might cause time-dilation. And linear acceleration changes reference frames to cause time dilation, and centrifugal acceleration changes the reference frame but doesn't cause time-dilation. Is that close to what you're saying? | |
| Sep 23, 2018 at 21:30 | comment | added | WillO | @StuartVanHorne: Sorry, this didn't quite fit in the last box. Turning around in a can only change your frame by the action of an element of $SO(3)$ (imbedded in $SO(3,1)$ in the obvious way) and so can't contribute to special relativistic time dilation. | |
| Sep 23, 2018 at 21:24 | comment | added | WillO | @StuartVanHorne: The acceleration has exactly as much to do with the time dilation as the twins' names do. This is easiest to see if you eliminate the acceleration entirely by having Bob turn around in literally an instant, so he is outbound up to and including time $T$ and inbound thereafter. Then at every single instant along the journey, Bob and Alice see each other's clocks run slow by exactly the same amount. The resolution of the "paradox" is that Bob, at some point, changes frames, not that he accelerates. Spinning in a centrifuge changes only the spatial part of your frame. | |
| Sep 23, 2018 at 21:18 | comment | added | Stuart Van Horne | @WillO, certainly not. I'm actually changing the underlying cause of the time-dilation. acceleration --> velocity --> time-dilation | |
| Sep 23, 2018 at 21:13 | history | edited | Stuart Van Horne | CC BY-SA 4.0 |
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| Sep 23, 2018 at 21:10 | comment | added | WillO | @StuartVanHorne : In many presentations of the Twin paradox, one twin is male (often named Bob) and the other is temale (often named Alice). If I make both the twins male is that a new (related) paradox or the same paradox with a new dressing? | |
| Sep 23, 2018 at 20:54 | comment | added | Stuart Van Horne | @WillO, I would suggest that this scenario is a new (related) paradox, not the same paradox with a new dressing. The standard twins paradox involves 1 twin experiencing acceleration and the other not. This scenario involves both twins experiencing the same acceleration, just in different directions. | |
| Sep 23, 2018 at 20:47 | history | edited | Stuart Van Horne | CC BY-SA 4.0 |
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| Sep 23, 2018 at 13:36 | comment | added | BioPhysicist | @WillO I think you are being pretty harsh here. The case of acceleration and the case of something like wearing a hat are not on the same conceptual footing. You could have just posted a great answer to this question based on what you are saying in your comments. | |
| Sep 23, 2018 at 6:46 | comment | added | WillO | @Kenshin: I think you are mistaken, actually. If I treat you as a point particle (as we always do in SR) then your worldline is exactly the same whether you spin or not, so the spinning has exactly the same effect on the equations as a red hat would, i.e. no effect at all. | |
| Sep 23, 2018 at 4:58 | comment | added | Kenshin | @WillO, I think the mathematics of special relativity within a centrifuge (which does enter into the equations) are are lot more complex than the mathematics of special relativity when wearing a red hat (which doesn't enter into the equations). | |
| Sep 23, 2018 at 4:20 | comment | added | WillO | (CONTINUED) c) if you take a few minutes to read through any one of the six kajillion good explanations of the twin paradox that are already on this site, it's crystal clear that they're not going to change if you put a twin in a centrifuge. I very much think that before asking a question like this, the OP should have read one of those answers, stuck in his centrifuge, and looked to see if it changed anything. | |
| Sep 23, 2018 at 4:18 | comment | added | WillO | @kenshin: Yes, but it's also perfectly logical to think that color of one's hat breaks the symmetry in the twin paradox. The question is not whether it's logical, but whether it's a reasonable thing for the questioner to have thought about before posting. There's room for disagreement about where to draw the dividing line, but to me it seems that a) a very small amount of noodling around with equations will dispose of this misconception, b) it's reasonable to expect the OP to have done that noodling around, and in any event (CONTINUED), | |
| Sep 23, 2018 at 3:52 | comment | added | Kenshin | @WillO, I don't think this question is quite like those examples. The question's misunderstanding was that it is the "acceleration" that breaks the symmetry in the twin paradox, and thus posits what happens if both twins undergo acceleration. This is a perfectly logical question to ask, and happens to have a simple solution. | |
| Sep 23, 2018 at 3:32 | comment | added | WillO | @kenshin: If you're going to allow the question "How do you resolve the twin paradox when one twin sits in a centrifuge?" then you've also got to allow the question "How do you resolve the twin paradox when one twin wears a red hat?" or "How do you resolve the twin paradox when one twin is a mezzosoprano?", and for that matter "Is momentum still conserved on holidays?" There is no end to asking the same question over and over with some new irrelevant hypothesis tacked on. I don't think it's a good idea to allow such questions. | |
| Sep 23, 2018 at 2:52 | comment | added | Kenshin | @WillO, can you elaborate on why the quesiton should be closed? Just because a simple solution may exist, doesn't mean a question needs to be closed in my opinion | |
| Sep 23, 2018 at 1:45 | review | Close votes | |||
| Sep 24, 2018 at 13:06 | |||||
| Sep 23, 2018 at 1:28 | comment | added | WillO | All of the acceleration is at the same 1g, so both twins are equally affected by gravitational time dilation, so you can ignore that part. Once you've ignored it, this is just the usual twin paradox, with the usual resolution. This question should certainly be closed. | |
| Sep 23, 2018 at 1:20 | comment | added | BioPhysicist | How did you specifically do this analysis. If there is something wrong this could help point out what it is. | |
| Sep 23, 2018 at 1:18 | answer | added | JEB | timeline score: 2 | |
| Sep 23, 2018 at 0:45 | review | First posts | |||
| Sep 23, 2018 at 3:32 | |||||
| Sep 23, 2018 at 0:40 | history | asked | Stuart Van Horne | CC BY-SA 4.0 |