Strange Posted January 1, 2018 Share Posted January 1, 2018 (edited) 2 hours ago, Estranged said: I'm sorry I didn't see your response before. So you agree that age and clock rates can have time differences. That means that it's possible that if a person travels at a very high speed away from Earth and comes back a very high speed, then their age could be just the same as someone who stayed on Earth the whole time. You asked a slightly ambiguous question and got an answer that matched one interpretation but not the one you are putting on it! The important point here is that time dilation is not an effect on the clock. It can't be. For example, right now you are traveling at 0 km/h relative to your chair (no time dilation) you are also travelling at hundreds of miles per hour relative to Mars (a bit of time dilation) you are also travelling at 99% of the speed of light relative to cosmic rays (a lot of time dilation). Your clock can't be running at multiple different speeds, affected by every relative velocity. It is purely a change in the way one person observes another frame of reference. They won't see your clock running at one sped, your wristwatch running at another and your body clock unchanged. They will measure everything changed by the same, relative, amount. Edited January 1, 2018 by Strange 2 Link to comment Share on other sites More sharing options...
beecee Posted January 1, 2018 Share Posted January 1, 2018 1 hour ago, Estranged said: The most public explaining I've tried to do is right here. This stuff has really been bothering me to the extent it interferes with my life. And it seems like no one can really answer me. I just googled "science forums" and I got here. I don't know what else to do. Sure you have been answered, many times right here. Relativity is termed relativity simply because time is relative. Every individual in every situation will feel time pass both mechanically and biologically at one second per second. It is only when one compares his own rate of the passage of time with another, that dilation or discrepancies are noticed. At Earthly based speeds and distances though, the difference in effect is very tiny and was not noticed until Einstein came along. You can rest assured though that it is real and has been verified observationally and experimentally particularly in particle accelerators and also our GPS system.. 2 Link to comment Share on other sites More sharing options...
beecee Posted January 1, 2018 Share Posted January 1, 2018 If you are asking why time dilation occurs, that is best answered by another Einstein fact, that being that the speed of light is the same for every observer no matter his or her frame of reference. This can be further explained by the following..... http://www.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/Special_relativity_clocks_rods/index.html What happens when a light clock is set into rapid motion, close to the speed of light? It is easy to see without doing any sums that the light clock will be slowed down. That is, it will be slowed down in the judgment of someone who does not move with the light clock. First, we will take the simple case of a light clock whose motion is perpendicular to the rod. The light clock will function as before. But now there is an added complication. The light signal leaves one end of the rod and moves toward the other end. But since the rod is moving rapidly, the light signal must chase after the other end as it flees. As a result, the light signal requires more time to reach the other end of the rod. That means that the moving light clock ticks more slowly than one at rest. Remember the light postulate. It tells us that the light always travels at the same speed in any inertial frame of reference. That the rod along which it bounces is moving rapidly will not alter the speed of the light. Here's an animation that shows a light clock at rest and a second light clock that moves perpendicular to its rod. The light signal in the moving clock chases after the rod. To reach the other end, it covers more distance and, as a result, requires more time. Here's the same animation in larger size in case you have a big screen. If you watch the animation carefully, you will see that the moving light clock ticks at exactly half the speed of the resting clock. That is because the light signal of the moving clock has to cover twice the distance to go from one end of the rod to the other. ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: The article further explains why length contraction also takes place, and why one second always passes at one second per second, within one's own frame of reference. 2 Link to comment Share on other sites More sharing options...
studiot Posted January 1, 2018 Share Posted January 1, 2018 3 hours ago, Estranged said: The most public explaining I've tried to do is right here. This stuff has really been bothering me to the extent it interferes with my life. And it seems like no one can really answer me. I just googled "science forums" and I got here. I don't know what else to do. Well you haven't said much about my posts, perhaps you missed them in the barrage. One of them was about observing this 'fixed' clock. The point being that the observation takes time and can't proceed faster than light. This simple fact needs to be taken into consideration on any accounting of what is seen (observed) by two observers in relative motion. 1 Link to comment Share on other sites More sharing options...
Mordred Posted January 1, 2018 Share Posted January 1, 2018 excellent point Link to comment Share on other sites More sharing options...
studiot Posted January 1, 2018 Share Posted January 1, 2018 2 hours ago, beecee said: If you are asking why time dilation occurs, that is best answered by another Einstein fact, that being that the speed of light is the same for every observer no matter his or her frame of reference. This can be further explained by the following..... http://www.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/Special_relativity_clocks_rods/index.html What happens when a light clock is set into rapid motion, close to the speed of light? It is easy to see without doing any sums that the light clock will be slowed down. That is, it will be slowed down in the judgment of someone who does not move with the light clock. First, we will take the simple case of a light clock whose motion is perpendicular to the rod. The light clock will function as before. But now there is an added complication. The light signal leaves one end of the rod and moves toward the other end. But since the rod is moving rapidly, the light signal must chase after the other end as it flees. As a result, the light signal requires more time to reach the other end of the rod. That means that the moving light clock ticks more slowly than one at rest. Remember the light postulate. It tells us that the light always travels at the same speed in any inertial frame of reference. That the rod along which it bounces is moving rapidly will not alter the speed of the light. Here's an animation that shows a light clock at rest and a second light clock that moves perpendicular to its rod. The light signal in the moving clock chases after the rod. To reach the other end, it covers more distance and, as a result, requires more time. Here's the same animation in larger size in case you have a big screen. If you watch the animation carefully, you will see that the moving light clock ticks at exactly half the speed of the resting clock. That is because the light signal of the moving clock has to cover twice the distance to go from one end of the rod to the other. ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: The article further explains why length contraction also takes place, and why one second always passes at one second per second, within one's own frame of reference. This explanation could be very confusing, unless you explain why the light 'signal' travels vertically in the first clock and diagonally in the second. Link to comment Share on other sites More sharing options...
geordief Posted January 1, 2018 Share Posted January 1, 2018 (edited) 9 minutes ago, studiot said: This explanation could be very confusing, unless you explain why the light 'signal' travels vertically in the first clock and diagonally in the second. That's because the lines connect where the expanding sphere of light is absorbed:/reflected by the top and bottom surfaces of the clock apparatus? Edited January 1, 2018 by geordief 1 Link to comment Share on other sites More sharing options...
Outrider Posted January 1, 2018 Share Posted January 1, 2018 10 minutes ago, studiot said: This explanation could be very confusing, unless you explain why the light 'signal' travels vertically in the first clock and diagonally in the second. Because the resting clock is moving through time only while the moving clock is moving through time and space? X-posted with geordief Link to comment Share on other sites More sharing options...
studiot Posted January 1, 2018 Share Posted January 1, 2018 Two different explanations; that is why I called it is confusing. 5 minutes ago, Outrider said: Because the resting clock is moving through time only while the moving clock is moving through time and space? This is incorrect, it has nothing to do with the motion of the clock. 8 minutes ago, geordief said: That's because the lines connect where the expanding sphere of light is absorbed:/reflected by the top and bottom surfaces of the clock apparatus? Yes that's it, well done. +1 It is not helped by the diagram which shows a distinct pulse of light. Link to comment Share on other sites More sharing options...
geordief Posted January 1, 2018 Share Posted January 1, 2018 13 minutes ago, Outrider said: Because the resting clock is moving through time only while the moving clock is moving through time and space? X-posted with geordief Both clocks are at rest(and so move only in time) in their own frame of reference But both also are in motion (and so move through both space and time) when viewed from the frame of reference of the other clock (or any other moving object) Link to comment Share on other sites More sharing options...
Estranged Posted January 1, 2018 Author Share Posted January 1, 2018 The important point here is that time dilation is not an effect on the clock. It can't be. For example, right now you are traveling at 0 km/h relative to your chair (no time dilation) you are also travelling at hundreds of miles per hour relative to Mars (a bit of time dilation) you are also travelling at 99% of the speed of light relative to cosmic rays (a lot of time dilation). Your clock can't be running at multiple different speeds, affected by every relative velocity. OK, that's all fine, but does it have to do with human age? -1 Link to comment Share on other sites More sharing options...
studiot Posted January 1, 2018 Share Posted January 1, 2018 6 minutes ago, Estranged said: The important point here is that time dilation is not an effect on the clock. It can't be. For example, right now you are traveling at 0 km/h relative to your chair (no time dilation) you are also travelling at hundreds of miles per hour relative to Mars (a bit of time dilation) you are also travelling at 99% of the speed of light relative to cosmic rays (a lot of time dilation). Your clock can't be running at multiple different speeds, affected by every relative velocity. OK, that's all fine, but does it have to do with human age? What meaning do you ascribe to the emboldened statement? Link to comment Share on other sites More sharing options...
Endy0816 Posted January 1, 2018 Share Posted January 1, 2018 1 minute ago, Estranged said: OK, that's all fine, but does it have to do with human age? Less time can pass for one individual vs another. Link to comment Share on other sites More sharing options...
Estranged Posted January 1, 2018 Author Share Posted January 1, 2018 1 minute ago, studiot said: What meaning do you ascribe to the emboldened statement? The clock can't be running at multiple speeds, right? It can run at one or the other, not both. Correct? Link to comment Share on other sites More sharing options...
studiot Posted January 1, 2018 Share Posted January 1, 2018 8 minutes ago, Estranged said: The clock can't be running at multiple speeds, right? It can run at one or the other, not both. Correct? How can this be correct or otherwise? What does the speed of a clock mean? Link to comment Share on other sites More sharing options...
swansont Posted January 1, 2018 Share Posted January 1, 2018 1 hour ago, Outrider said: Because the resting clock is moving through time only while the moving clock is moving through time and space? X-posted with geordief The speed through spacetime is constant. So time runs more slowly when a clock is not at rest. 27 minutes ago, Estranged said: The important point here is that time dilation is not an effect on the clock. It can't be. For example, right now you are traveling at 0 km/h relative to your chair (no time dilation) you are also travelling at hundreds of miles per hour relative to Mars (a bit of time dilation) you are also travelling at 99% of the speed of light relative to cosmic rays (a lot of time dilation). Your clock can't be running at multiple different speeds, affected by every relative velocity. OK, that's all fine, but does it have to do with human age? You are always at rest, if we are limited to inertial motion. Any velocity you have relative to anything else is according to some observer in a different frame of reference. It is other observers who see your clock as running slow. It's nonsensical to talk about a clock running a multiple speeds. Observers disagree in their measurement of the clock rate. It's not an invariant quantity. Neither are length, or kinetic energy. Link to comment Share on other sites More sharing options...
Strange Posted January 1, 2018 Share Posted January 1, 2018 (edited) 28 minutes ago, Estranged said: OK, that's all fine, but does it have to do with human age? Because someone moving relative to you will see time passing at a different rate. That includes your pulse, bodily functions and aging. They don’t see your clock going wrong because they are moving. They see different elapsed time: ticks of your clock, beats of your heart, etc. Edited January 1, 2018 by Strange Link to comment Share on other sites More sharing options...
geordief Posted January 1, 2018 Share Posted January 1, 2018 (edited) 35 minutes ago, swansont said: The speed through spacetime is constant. What is that speed? Is it the same for all objects in the universe? Some kind of a universal constant? Edited January 1, 2018 by geordief Link to comment Share on other sites More sharing options...
studiot Posted January 1, 2018 Share Posted January 1, 2018 (edited) Quote Time and speed and how speed impacts time The OP is using two entirely different definitions for the word speed. No wonder he is confused. 7 minutes ago, geordief said: What is that speed? Is it the same for all objects in the universe? Some kind of a universal constant? I recommend you avoid this trap. Edited January 1, 2018 by studiot Link to comment Share on other sites More sharing options...
beecee Posted January 1, 2018 Share Posted January 1, 2018 1 hour ago, studiot said: This explanation could be very confusing, unless you explain why the light 'signal' travels vertically in the first clock and diagonally in the second. The second clock is in motion and consequently more distance is covered. As the speed of light, "c" is constant, which means that time will appear longer. 7 minutes ago, geordief said: What is that speed? Is it the same for all objects in the universe? Some kind of a universal constant? The speed of light is the universal constant. Perhaps I'm just an old cynic, but I see a certain pattern developing with the questioner in the OP...perhaps I'm wrong...let's see. Link to comment Share on other sites More sharing options...
geordief Posted January 1, 2018 Share Posted January 1, 2018 (edited) 3 minutes ago, studiot said: I recommend you avoid this trap. But it is c surely ?(as I realized after posting) Edited January 1, 2018 by geordief Link to comment Share on other sites More sharing options...
studiot Posted January 1, 2018 Share Posted January 1, 2018 Just now, beecee said: The second clock is in motion and consequently more distance is covered. As the speed of light, "c" is constant, which means that time will appear longer. That is not an explanation as to why the second diagram shows a diagonal path. 2 minutes ago, beecee said: The speed of light is the universal constant. Perhaps I'm just an old cynic, but I see a certain pattern developing with the questioner in the OP...perhaps I'm wrong...let's see. Perhaps that is why he doesn't want to engage my questions? 3 minutes ago, geordief said: But it is c surely ?(as I realized after posting) He is using speed as in the conventional sense of the magnitude of a velocity in the title. He is confusing himself by talking about the 'speed of time', which is undefined in Physics and certainly not a velocity. At best I can say it is one of the ghosts of the absolute I referred to before, because it implies a comparison with some base 'absolute' speed. Link to comment Share on other sites More sharing options...
beecee Posted January 1, 2018 Share Posted January 1, 2018 2 minutes ago, studiot said: That is not an explanation as to why the second diagram shows a diagonal path. From the point of view of an observer on a train station platform, say viewing the light clock in a moving train? Quote Perhaps that is why he doesn't want to engage my questions? Perhaps....As I said, I hope I am wrong. Link to comment Share on other sites More sharing options...
geordief Posted January 1, 2018 Share Posted January 1, 2018 (edited) 10 minutes ago, studiot said: He is using speed as in the conventional sense of the magnitude of a velocity in the title. I was just picking up Swansont who referred to the "speed of spacetime" being constant http://www.scienceforums.net/topic/112539-time-and-speed-and-how-speed-impacts-time/?do=findComment&comment=1031526 Not realizing this "speed" was c I wanted to know more about this strange constant speed. Edited January 1, 2018 by geordief Link to comment Share on other sites More sharing options...
studiot Posted January 1, 2018 Share Posted January 1, 2018 3 minutes ago, beecee said: From the point of view of an observer on a train station platform, say viewing the light clock in a moving train? Perhaps....As I said, I hope I am wrong. I don't think you are catching my point. Say the stationary clock emits red light and the other blue light. The diagram you have shown refers to red light only, The pulse should be drawn as a wave front of the red light that intersects the path of the other clock and bounces off its upper mirror to achieve the diagonal path shown. As far as the blue light is concerned it always starts from the bottom of the travelling rod and bounces off the upper mirror of the travelling clock, travelling exactly the same distance as the red light in the stationary clock. 2 minutes ago, geordief said: I was just picking up Swansont who referred to the "speed of spacetime" being constant http://www.scienceforums.net/topic/112539-time-and-speed-and-how-speed-impacts-time/?do=findComment&comment=1031526 Not realizing this "speed" was c I wanted to know more about this strange constant speed. Swansont was not asking questions, he was trying to answer them and note he specified spacetime not time or space separately. The interval is a spacetime invariant. Link to comment Share on other sites More sharing options...
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