by Jackslap
P: 8,470
 Quote by TcheQ It's not relevant to the understanding of the implications of time dilation.
The question was not solely about the implications of time dilation. As Fredrik said, this part of Jackslap's question seemed to require a response discussing how simultaneity isn't absolute in relativity:
 Quote by Jackslap I started thinking of it like this: If it were possible for twins to be born at the same instant on opposite sides of the galaxy, and then relocated instantly to a neutral location, wouldn't they be the same? The earth years number is just an arbitrary number that WE use because it's how we understand time. The human body does it's own thing.
 P: 1,084 maybe to make it slightly more clear. in 1 second on earth, twin A's biological clock will carry out the same actions as twin B's biological clock will in a second. The only thing different is that if on earth 2 seconds pass, 1 second will pass at .866c. I think this is where your understanding breaks down. biological clock is dependent on time and time is dependent on speed. so at higher speeds, the biological is not affected by speed. say we want to define the biological processes of the brain(hormones etc) in a "reaction per second" unit. as you can see, no matter what speed there will be, there will still be the same reactions per seconds carried out by the brain. The only thing different between twin A and twin B is the amount of seconds that has passed, not the rate of biological processes. You're right, this topic is mind blowing, keep asking questions. more questions, more answers, more understanding.
 P: 48 Relativity eschews the concept of an absolute reference inertial frame. To conclude that one twin ages at a different rate than the other would require one to assign an absolute reference frame to one twin; in the case of the 'paradox', twin A. This actually violates Special Relativity. Both twins age at the same rate. Ron
P: 1,084
 Quote by W.RonG Relativity eschews the concept of an absolute reference inertial frame. To conclude that one twin ages at a different rate than the other would require one to assign an absolute reference frame to one twin; in the case of the 'paradox', twin A. This actually violates Special Relativity. Both twins age at the same rate. Ron
which is what i said more or less in layman's terms.
P: 58
 Quote by JesseM The question was not solely about the implications of time dilation. As Fredrik said, this part of Jackslap's question seemed to require a response discussing how simultaneity isn't absolute in relativity:
I guess that's the problem with using (extremely poor) examples that can't ever be tested or observed. After all the twin paradox is just a spoon feeding to the gelatinous-cube masses to simulate what happens to particles and to make physics sound cooler than it really is (but it's already sub -273C°!)

 Quote by Fredrik So why the attitude? If you want to give him those "simple answers", then just do it. Save the agression for a time when its appropriate.
What is the point of one person giving simple answers to the degree of t/gamma, and the rest quoting enough journal articles and mathematical fluff to fill the Mir space station? The problem in #7 was still time dilation, and instead of saying "actually that's an extremely poor example who's details severely detracts from the original question, let's use a better one" you did the complete opposite. The fact that one entity is travelling at a speed required for the observance of time dilation is unimportant.

Perhaps I just find it unbelievable that after the number of posts I see, people are still unable to communicate it in a simple manner. It's basics. If people really want to learn more about it, lectures on youtube, books or shockhorror even university courses are readily available.
 P: 23 I sure did not mean to stir up an argument, but I have to admit that I did sort of confuse the matter in #7. My thought pattern lead me from one thing to another, and I discussed both thoughts in that one, unintentionally changing the subject a bit. One wrong thought led to another wrong thought. I believe my error stemmed from taking the twin paradox idea and changing it so that BOTH twins would now be moving, instead of one staying still and the other accelerating. Plus introducing the impossible idea of instant relocation of matter. But now that I've said that, haven't I just brought up some other principle? Something about how it doesn't matter which twin is moving, that one twin could always consider his frame is the moving frame and the other standing still? I know that I just changed the subject again, but this is all leading me toward better understanding. Essentially the twin that is hurtling through space AWAY from earth at .866c could merely consider that earth is really just moving AWAY from him at .866c and he's still right? Thanks to Tcheq, dacruick, and Fredrik for the recent chip ins. Your past few posts have really given me some things to study and have helped me graps this a bit better. I wish I had the time and money to study this full time in school. How much did you all spend for your degrees? Worth every penny I'm sure. You all know stuff that average fools like me can't begin to fathom.
P: 48
 Quote by Jackslap ... I believe my error stemmed from taking the twin paradox idea and changing it so that BOTH twins would now be moving, instead of one staying still and the other accelerating. ...
This is the crux of the misunderstanding. Neither twin is 'staying still'. Unfortunately everything is moving relative to something else. That is why no clock actually runs slower than any other clock. The appearance of time dilation is not an actual slowing of anything, only a phenomenom applied to an observer's observation of a different inertial frame. Remember, there is no absolute reference frame.
Ron
 P: 23 Damn you Ron for taking all of my "almost there" understanding and throwing a bomb in it! I understand everything you just said. I can accept it as fact. But then how is it that time dilation is not a slowing of anything? I had just established that one twin is actually younger than the other one upon returning to earth (or earth returning to him depending on perspective). But if nothing really slows, why are their ages different? Am I taking you guys in cirlces here or what? Sorry to bother if so. I do however understand that there is no absolute reference frame though. What that means to me is that if I, a neutral observer in this traveling twin thought, were to see the whole thing unfold from some point other than twin A or B, I would see things different than either of them did. Meaning that there really is no neutral way to observe this event. Everyone will have a difference of opinion of what really happend based on their own location.
 P: 48 Yeah I know. I actually took a long time to phrase the first post I made in this thread. I could already hear the screams of 'blasphemy' and 'heretic'! But the simple fact is that any observer is as preferred as any other; no more, no less. The actual 'paradox' is only in the phrasing of the riddle. By saying 'B' appears to 'A' to be running slower does not translate to the oft-quoted conclusion that 'B' is in reality running slower than 'A'. Just keep repeating: there is no absolute reference inertial frame, there is no absolute reference inertial frame, there is no absolute reference inertial frame . . . Ron
 P: 23 This link is helping me somewhat. http://casa.colorado.edu/~ajsh/sr/timebig.html I understand the clocks and time dilation sections, but when I get to the Lorentz Gamma Factor and the Paradox image I get lost again. The fact that the red perspective stays horizontal I get, but why does the blue need to be placed on a diagonal with a skewing of his "cone" area? Is this like the Einstein example of the ball being dropped from a train? That it travels on a diagonal to a "stationary" observer at the train station?
 P: 48 Keep in mind that what I've said flies directly in the face of about a century of some very smart people saying some very wrong things. I really don't have much hope of changing minds here with my humble postings, but I could not just sit here and let the fallacious ideas continue unchallenged. Even that really really smart guy on Discover channel gets it wrong. Neither clock slows down. End. Ron
 P: 23 Wow! O.K. Ron I did not understand that you were actually challenging the facts that the other posters were bringing up, I thought I was misunderstanding you. You are saying that in your opinion neither twins age would be different then? Because that was my first instinct, but I thought everyone here had solved for me why I was wrong. So now we really have come full circle. Ron, why then is there still a debate about this? After a hundred years like you said, why isn't there an agreement yet? Surely someone has nailed this down definitively right?
 P: 48 Not really challenging facts, just keeping the conclusions in check. I understand and believe in Special Relativity. In doing so, and being intellectually consistent and honest, I can only conclude that a clock moving relative to another clock appears to tick more slowly but in fact does not actually tick more slowly. Again, to conclude that it does would be to assign preference to the faster clock. This is a violation of SR. Thanks, Ron
 P: 23 So I have just only begun to understand the difference between GR and SR according to lectures on youtube (thanks TcheQ for the suggestion, why didn't I think of that?). Ron, you are saying then that there is still a group of people who don't believe in SR? I only ask that because you singled yourself out by saying "I believe in SR" as though some don't. Why the debate, shouldn't special relativity just be accepted as fact? Someone is saying Einstein was wrong? What have I missed? BTW, my wife says I'm turning into an internet physics nerd. I said "You should see what THESE guys are saying, you think I'm nerdy"... The thing is she loves her some nerds. She has a secret crush on Conan O'brien. Yuck
 P: 48 There may be some who do not understand or believe in SR. I made that statement as a pre-emptive defense against someone who might claim that I don't. The mathematics of SR are basically inarguable. One thing that could possibly negate SR is if someone were to show that an observer measures something other than the same well-established c for the (local) speed of light. That woukl be earth-shattering. Meanwhile the Theory, if kept within its limitations, works quite well. (I have actually downloaded a copy of On the Electrodynamics of Moving Bodies in English, read it, and understand it.) I've avoided posting any opinion yet in this thread. Since you asked, I think that some people get so buried in the fantastical specific notions implied by Relativity that they lose sight of reality. In constructing a particular Gedanken like the 'twins paradox', one must be careful to maintain the aforementioned intellectual integrity. The key is to always remember the two postulates stated by Einstein in his paper; this should help keep things grounded. Another thing to keep in mind is that Einstein (and others) have described various physical actions but still have not explained the actions. Fodder for another thread . . . Ron
Emeritus
PF Gold
P: 9,403
 Quote by W.RonG This is the crux of the misunderstanding. Neither twin is 'staying still'. Unfortunately everything is moving relative to something else. That is why no clock actually runs slower than any other clock. The appearance of time dilation is not an actual slowing of anything, only a phenomenom applied to an observer's observation of a different inertial frame. Remember, there is no absolute reference frame.
There's nothing controversial in here.
 Quote by W.RonG Yeah I know. I actually took a long time to phrase the first post I made in this thread. I could already hear the screams of 'blasphemy' and 'heretic'! But the simple fact is that any observer is as preferred as any other; no more, no less. The actual 'paradox' is only in the phrasing of the riddle. By saying 'B' appears to 'A' to be running slower does not translate to the oft-quoted conclusion that 'B' is in reality running slower than 'A'. Just keep repeating: there is no absolute reference inertial frame, there is no absolute reference inertial frame, there is no absolute reference inertial frame . . .
...or here. It just sounds like you want people to call you a blasphemer.

 Quote by W.RonG Keep in mind that what I've said flies directly in the face of about a century of some very smart people saying some very wrong things. I really don't have much hope of changing minds here with my humble postings, but I could not just sit here and let the fallacious ideas continue unchallenged. Even that really really smart guy on Discover channel gets it wrong. Neither clock slows down. End.
I have no problem believing that Discovery channel gets it wrong, but it still sounds like you just believe people are saying things they aren't actually saying. I agree that the function of a clock is in no way disturbed when it's given a different velocity. It's still measuring the proper time of the curve that represents its motion, but that's now a different curve than before.

 Quote by W.RonG Not really challenging facts, just keeping the conclusions in check. I understand and believe in Special Relativity. In doing so, and being intellectually consistent and honest, I can only conclude that a clock moving relative to another clock appears to tick more slowly but in fact does not actually tick more slowly. Again, to conclude that it does would be to assign preference to the faster clock. This is a violation of SR.
But it does "actually" tick more slowly in the other guys reference frame. (It would however be wrong to end the sentence after "slowly"). If A and B don't have the same velocity, then A's clock is slow in B's frame, and B's clock is slow in A's frame.
 P: 48 Far be it for me to take on Mr. Michio Kaku, the really really smart guy I was referring to. But I have watched the shows he narrated about Time and remember distinctly the leap he made from stating one clock appears to another to be ticking more slowly, to the statement (after a commercial break) that one clock is really ticking more slowly than the one that is implicitly now preferred. The conclusion was unmistakable due to the implications of long distance space travel being accomplished by flying really fast (compared to what? is the question), same as the 'twins paradox'. The popular notion is that one clock, and one twin, experiences time flow more slowly, is pervasive and just plain wrong. Hope we agree. Ron
Emeritus
PF Gold
P: 9,403
 Quote by Jackslap This link is helping me somewhat. http://casa.colorado.edu/~ajsh/sr/timebig.html I understand the clocks and time dilation sections, but when I get to the Lorentz Gamma Factor and the Paradox image I get lost again.
The derivation of gamma is easy if you understand the pythagorean theorem. There are lots of proofs on the Wikipedia page. I like the one in the "algebraic" proof section. You just note that the area of the larger square is equal to the sum of the area of the smaller (light blue) square and the areas of the 4 triangles. When you write that down and simplify the expression, you get the pythagorean theorem.

 Quote by Jackslap The fact that the red perspective stays horizontal I get, but why does the blue need to be placed on a diagonal with a skewing of his "cone" area?
The argument can be made more rigorous than I'm making it here, but it still uses the same basic idea. Cerulean's spatial plane has to be tilted by the same amount and in the opposite direction as his time axis, because otherwise a line that's exactly half-way between Vermilion's time axis and his spatial plane wouldn't be exactly half-way between Cerulean's time axis and his spatial plane. (A line that's exactly half-way between the time axis and the spatial plane represents the motion of something that's moving at the speed of light, which is =1 in the units we're using in these diagrams, and is supposed to be the same in all frames. So if we don't tilt the spatial plane, we're either contradicting that assumption, or the assumption that no frame is fundamentally different from any other).

 Quote by Jackslap Is this like the Einstein example of the ball being dropped from a train? That it travels on a diagonal to a "stationary" observer at the train station?
Yes, that's sounds like an accurate description of what's going on in the time dilation picture.

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