James Putnam 187 Posted June 17, 2008 Author Report Share Posted June 17, 2008 Time and space has to be included in any physics framework or you would not be able to make predictions about future events from past and present data events and therefore your physics would be ultimately useless as it would make no predictions. Physics is a mathematical model of the universe, to model it properly you are forced by convention to adopt a spacetime approach. Do you have another way of accurately modelling the universe without time ie can you progress the model forwards in time and make predictions ? Peace:shade: [speaking just about the use of space and time in theory) Its length and cyclic motion that we have to work. Calling these two space and time is unwarranted by any empirical evidence. It is found that length shortens and cyclic motion slows as an object nears a body of matter, but, that is the empirical evidence we should be working from. Cyclic motion changes with respect to time and and somehow it, theoretically, becomes time itself that has changed. The increase in energy of light as it approaches the earth tells us important information about light and matter, but not about space or time. James Quote Link to post Share on other sites

snoopy 3,602 Posted June 17, 2008 Report Share Posted June 17, 2008 The increase in energy of light as it approaches the earth tells us important information about light and matter, but not about space or time. James I agree. But how do you intend to model it ? Its unclear to me how this could possibly be achieved you cant use matrices as you would inevitably end up modelling a spacetime of some sort. A grid system of coordinates also seems to be out of the question as you would end up with semi-independant dimensions of space but you would have to include time somehow even if it you only conclude its a function of matter and energy or something else like that. How do you propose to solve it... you definitely have to include time somewhere so where and how would be my question ?? Peace:shade: Quote Link to post Share on other sites

modest 398,851 Posted June 17, 2008 Report Share Posted June 17, 2008 Also, there is no need to "dumb down" physics simply because people who are too lazy to study or too stupid to understand haven't yet figured out how words are properly used in this context. Clock dilation? Really? Come on... I agree with this James. There is no need to start inventing terms. You can look up "proper time" and "coordinate time" and I think you'll find physics has done a good job of creating appropriate terms that apply to what you're trying to say. -modest Quote Link to post Share on other sites

James Putnam 187 Posted June 17, 2008 Author Report Share Posted June 17, 2008 I agree with this James. There is no need to start inventing terms. You can look up "proper time" and "coordinate time" and I think you'll find physics has done a good job of creating appropriate terms that apply to what you're trying to say. -modest You agree with what parts. Am I too stupid to understand? Is that what you think also? I know what proper time is. But that is not what is said. The word is 'time'. I say proper time is equivalent to clock time. Therefore, it is clock dilation and not time dilation. James Quote Link to post Share on other sites

modest 398,851 Posted June 17, 2008 Report Share Posted June 17, 2008 You agree with what parts. Am I too stupid to understand? Is that what you think also? I know what proper time is. But that is not what is said. The word is 'time'. I say proper time is equivalent to clock time. Therefore, it is clock dilation and not time dilation. James INow was not saying you were too stupid to understand anything. He was saying (which I strongly agree with) that you need not "dumb down" the terms you are using. Doing so both confuses people who are well versed on this subject and is a stumbling block for those who would like to become so. If you insist on declaring proper time is equivalent to "clock time" as you state above then simply use the term proper time. It is a commonly used term in physics and people will understand you. I fail to see the problem with that. -modest Quote Link to post Share on other sites

REASON 268,359 Posted June 17, 2008 Report Share Posted June 17, 2008 Therefore, it is clock dilation and not time dilation. James :) How can a clock be dilated? Quote Link to post Share on other sites

James Putnam 187 Posted June 17, 2008 Author Report Share Posted June 17, 2008 INow was not saying you were too stupid to understand anything. He was saying (which I strongly agree with) that you need not "dumb down" the terms you are using. Doing so both confuses people who are well versed on this subject and is a stumbling block for those who would like to become so. This is what you quoted. Originally Posted by InfiniteNow Also, there is no need to "dumb down" physics simply because people who are too lazy to study or too stupid to understand haven't yet figured out how words are properly used in this context. Clock dilation? Really? Come on... If you insist on declaring proper time is equivalent to "clock time" as you state above then simply use the term proper time. It is a commonly used term in physics and people will understand you. I fail to see the problem with that. -modest The problem is that Einstein's treatment of time has led to the theory of spacetime. Where does that leap of imagination come into play. Or, would you say that space really means proper length and time really means proper time. What is spacetime? Is it four dimensions that include three coordinates of real space and one of real time? Are real space and real time interdependent or is there simply a relationship between changes in length and measurements of time? None of this is meant to challenge you or your depth of knowledge. I would simply ask that an explanation be given that uses the words that accurately convey what is meant by spacetime. It would help in debate and might also be useful to general readers that have a strong interest in learning about Einstein's theories. James Quote Link to post Share on other sites

modest 398,851 Posted June 17, 2008 Report Share Posted June 17, 2008 The problem is that Einstein's treatment of time has led to the theory of spacetime. Or Minkowski's treatment of spacetime led to Einstein's special relativity. Either way, the Lorentz transformations are the correct treatment of the discussion at hand. They are a direct result of combining space and time into space-time. Where does that leap of imagination come into play. Or, would you say that space really means proper length and time really means proper time. What is spacetime? Is it four dimensions that include three coordinates of real space and one of real time? Are real space and real time interdependent or is there simply a relationship between changes in length and measurements of time? None of this is meant to challenge you or your depth of knowledge. I would simply ask that an explanation be given that uses the words that accurately convey what is meant by spacetime. It would help in debate and might also be useful to general readers that have a strong interest in learning about Einstein's theories. James In a Newtonian sense spatial distance is independent of temporal "distance". This is not exactly accurate, we've known for some time now. The correct treatment is a four vector on something like the Minkowski metric. This leads to many terms like: "light-like distance" "space-time interval" "proper time" or "coordinate time". These things are precisely defined in the metric and transformations linked above. I'm unsure exactly what it is about these concepts you wish to investigate. -modest Quote Link to post Share on other sites

James Putnam 187 Posted June 17, 2008 Author Report Share Posted June 17, 2008 Or Minkowski's treatment of spacetime led to Einstein's special relativity. Either way, the Lorentz transformations are the correct treatment of the discussion at hand. They are a direct result of combining space and time into space-time. In a Newtonian sense spatial distance is independent of temporal "distance". This is not exactly accurate, we've known for some time now. The correct treatment is a four vector on something like the Minkowski metric. This leads to many terms like: "light-like distance" "space-time interval" "proper time" or "coordinate time". These things are precisely defined in the metric and transformations linked above. I'm unsure exactly what it is about these concepts you wish to investigate. -modest This is why I work from the fundamentals step by step. Great leaps forward into complex theory and the terms that are born out of the theory do not address the question of: What have we learned about the operation of the universe that leads step by step toward fuller understanding. If Einstein's theory is correct, then we should be able to see the development of that theory step by step from the fundamentals. Transform equations force a relationship without going through this step by step approach. Transform equations are not safe mathematics for helping to learn truth about the operation of the universe. That is my opinion. I think now that this discussion probably is not going to settle anything. I respect your viewpoint. Thank you for your time. James Quote Link to post Share on other sites

Erasmus00 86,950 Posted June 17, 2008 Report Share Posted June 17, 2008 You agree with what parts. Am I too stupid to understand? Is that what you think also? I know what proper time is. But that is not what is said. The word is 'time'. I say proper time is equivalent to clock time. Therefore, it is clock dilation and not time dilation. Clock dilation implies that (for instance) while a clock would slow down perhaps other "measures" of time will not- i.e. a mechanical clock might slow, but a human heart might beat at the same rate, or an electric clock might go at the normal rate. However, we can synch a heart to a mechanical clock, so the heart must also slow down, etc. The key thing is that your "clock dilation" is independent of the clock (any clock), and hence is more properly ascribed to a property of time. -Will Quote Link to post Share on other sites

CraigD 398,736 Posted June 19, 2008 Report Share Posted June 19, 2008 This is why I work from the fundamentals step by step. This is not only a good approach, some might argue that it’s the only approach that actually works. While “leaps of intuition” are commonly reported in math and science, after such experiences, the mathematician or scientist must be able to present proof of their theorem or the derivation of their theoretical prediction in a formal, step-by-step manner.Great leaps forward into complex theory and the terms that are born out of the theory do not address the question of: What have we learned about the operation of the universe that leads step by step toward fuller understanding.True. For this reason, effective instruction in Math and Physics needs to, and in nearly all ordinary academic setting do, follow a series of well-explained, orderly, step-by-step explanations. Unfortunately, internet science forums - even one as esteemed as hypography ;) – aren’t like well-taught academic classes. People tend to discuss ideas assuming readers have about the same academic experience as they do, which is often not true. Being less formal and hierarchical than the usual class setting, we’re really not suited to ordinary academic communication – in short, science forums aren’t a substitute for science classes. Nonetheless, I’ll try to give an overview of physics sufficient to put time dilation in a sensible context.If Einstein's theory is correct, then we should be able to see the development of that theory step by step from the fundamentals.The theory of special relativity is very succinct and straight-forward in proceeding from its assumptions (postulates) to its conclusions. It begins with an earlier theory of relativity, Galilean relativity. To understand Galilean relativity, it’s helpful to consider what it is not, the pre and early scientific ideas that preceded it. In short, these views held that the laws of physics were different for moving bodies than “stationary” ones. This made intuitive sense, based on everyday experience: actions performed in the interiors of jostling horse-drawn carriages or pitching ships at sea seemed to obey different laws of motion than those done on solid ground. A natural conclusion of this view was geocentrism: if Earth was orbiting Sol at a great speed, surely we would feel it. The eventual acceptance of Galilean relativity went along with that of heliocentism, and continued to be accepted when Isaac Newton much improved its mathematical formalism. By the late 19th century, however, with the great successes of James Clerk Maxwell and others in describing electromagnetism and light as wave phenomena, the idea that Galilean relativity could be violated by such things as measurements of the speed of light from a moving body was widely entertained, culminating in the famous Michelson–Morley experiment, which attempted, in essence, to do just that, and, along with subsequent experiments, wound up not only supporting Galilean relativity, but adding to its list of laws of physics that were the same regardless of motion a new, and to many unexpected, item: the constancy of the speed of light. Hence, special relativity as described by Einstein has two postulates: the first, Galilean relativity; the second, that the speed of light in vacuum is constant.Transform equations force a relationship without going through this step by step approach. Transform equations are not safe mathematics for helping to learn truth about the operation of the universe. That is my opinion.Working from these two postulates, time dilation and the equation that describes it – usually called the Lorentz factor – follow from very simple geometry. The usual “though experiment” illustration of this is the “light clock”, which simply notes the difference in the path of a reflected pulse of light observed by a person stationary with respect to the apparatus vs. a person moving with respect to it. The shape of this path is a triangle. In the simplest units (known as Planck units) The Lorentz factor (or, precisely, its reciprocal) is just the famous Pythagorean formula for one side [math]B[/math] of a right triangle with a diagonal of length 1 given the length of the other side [math]A[/math]: [math]A = \sqrt{1-B^2}[/math]. This series of small steps of explanation allows us to answer part of this thread’s original question:What is the cause for this clock dilation? The clock's operation is a physical occurrence. Does empirical evidence indicate the reason for clock dilation? According to relativity, clocks do not run slower when in motion as perceived by an observer at rest relative to the clock. No sort of physical stress, shaking, etc. is involved – time dilation (it makes little sense, IMHO, to reject the most well known term for the effect for philosophical reasons) is simply a geometric effect due to differences in observers, somewhat analogous to effects such as geometric perspective. As is usually the case when that thorn-in-the-side of physics, gravity, is involved, things get more complicated - but no less explicable in a step-by-step manner - when one considers the gravitational time dilation of the general theory of relativity. It’s an educational tradition, therefore, for the student to become comfortable with special relativity before undertaking the study of general relativity. modest 1 Quote Link to post Share on other sites

The_Right_Stuff 41 Posted June 27, 2008 Report Share Posted June 27, 2008 ...This series of small steps of explanation allows us to answer part of this thread’s original question:According to relativity, clocks do not run slower when in motion as perceived by an observer at rest relative to the clock. No sort of physical stress, shaking, etc. is involved – time dilation (it makes little sense, IMHO, to reject the most well known term for the effect for philosophical reasons) is simply a geometric effect due to differences in observers, somewhat analogous to effects such as geometric perspective.....QUOTE] Yes, " According to relativity, clocks do not run slower when in motion as perceived by an observer at rest relative to the clock.", but according to reality, THEY DO ! Relativity itself has a foundation, or a cause. However, if one ignores the cause of Relativistic circumstances, then one ends up with circular arguments, since the complete truth of the matter is never included within the arguments. YouTube - TRUTH OVER BELIEF - PART ( 4 ) http://www.youtube.com/watch?v=6Nn12EsAMFA( Ignore the first 48 seconds ) As shown within the above video, if one was to measure the speed of light that is crossing the entirety of an object that is 300,000km in length, this occurrence would be measured as a 1 second event. Also as shown, this would be measured as a 1 second event, even if the 300,000km long object was in motion across Space at 260,000km per second, nor would it matter which way the light was to travel relative to the direction of the objects motion. The outcome of this measurement of the speed of light always gives the same results. This would also apply if one was to measure the speed of a super high speed bullet that was fired from one end of the 300,000km long object to the other. Here too, the results would always be the same no matter what velocity the 300,000km long object( or platform, or frame of reference, etc ) had across Space. But by no means does this happen without reason. Quote Link to post Share on other sites

modest 398,851 Posted June 27, 2008 Report Share Posted June 27, 2008 Yes, " According to relativity, clocks do not run slower when in motion as perceived by an observer at rest relative to the clock.", but according to reality, THEY DO ! You're either misunderstanding or you're going to need to give a source for this. You are saying that a person who accelerates three quarters of the speed of light will look at his wrist watch and see it moving slow? According to reality, you think that would happen - and you can support that? -modest Quote Link to post Share on other sites

The_Right_Stuff 41 Posted June 28, 2008 Report Share Posted June 28, 2008 You're either misunderstanding or you're going to need to give a source for this. You are saying that a person who accelerates three quarters of the speed of light will look at his wrist watch and see it moving slow? According to reality, you think that would happen - and you can support that? -modest I have said no such thing. I am saying that there is a foundation which is responsible for the creation of what is called Special Relativity. Thus the structure of reality itself must be observed, and not just what occurs due to the form of such a structure. Based on the description of constant motion of all objects present within the open 4 dimensional Time-Space environment, and the rotation of objects within Time-Space, which occurs as one changes ones direction of travel within that Time-Space environment, measurement instruments, clocks, rulers, etc, will all be effected in such a manner that any measurement of light will always give the same results no matter what velocity ones measurement platform has across Space. As the result of this, there is no way in which we can determine if one is at rest in space or not. Hence we are left with nothing but Relative comparisons between different so called frames of reference. But the fact that our measurement instruments change accordingly, thus giving us the same measurement of the speed of light no matter what our velocity is relative to another body, nor relative to light light itself, this reveals our own constant motion, and that the magnitude of this constant motion within Time-Space, is equal to the magnitude of motion of a photon's motion across Space. Further descriptions are available at.CONSTANT MOTION Quote Link to post Share on other sites

CraigD 398,736 Posted June 30, 2008 Report Share Posted June 30, 2008 Further descriptions are available at.CONSTANT MOTIONThe linked-to article (which appears to be present the same material as the previously posted youtube video) seems to me to unnecessarily complicate special relativity and time dilation. It seems to appeal to various intuitive ideas about reality and what is and isn’t clear to arrive at the usual formula for time dilation. However, as I mentioned in post #28:Hence, special relativity as described by Einstein has two postulates: the first, Galilean relativity; the second, that the speed of light in vacuum is constant.…Working from these two postulates, time dilation and the equation that describes it – usually called the Lorentz factor – follow from very simple geometry.I’ll try to show this simple derivation here, using a simplified version of the “light clock” thought experiment. A is an observer who measures a light signal traveling a distance [math]d[/math] from an emitter to a stationary target in [math]t_A[/math]. Knowing that light travels at a constant speed [math]c[/math], and the basic definition [math]\mbox{distance} = \mbox{speed} \cdot \mbox{time}[/math], A therefore can define [math]d = c \, t_B[/math]. This can be sketched:[math]\setlength{\unitlength}{1mm}\begin{picture}(0, 0)\put(1,25){ \makebox(0,0)[lc]{What A sees:} }\put(35,42){ \makebox(0,0)[cc]{target} }\put(35,10){ \vector(0,1){30} }\put(35,8){ \makebox(0,0)[cc]{emitter} }\put(36,25){ \makebox(0,0)[lc]{$d = c \, t_A$} }\end{picture}[/math] B is an observer measuring the same event – the light signal traveling from emitter to target. B, however, is moving at a speed [math]v[/math] relative to A in a direction perpendicular to the line between emitter and target (B can also be said to be in motion at the same speed in the opposite direction relative to A). B, however, sees the path of the light from emitter to target as being longer than d, and because the [math]c[/math] must be constant, the time the event takes [math]t_B[/math] to be longer. During the event, B measures the target, which is moving with A, to have moved a distance [math]v \, t_B[/math] [math]\setlength{\unitlength}{1mm}\begin{picture}(0, 0)\put(1,25){ \makebox(0,0)[lc]{What B sees:} }\put(42,43){ \makebox(0,0)[cc]{$v \, t_B$} }\put(50,42){ \makebox(0,0)[lc]{target} }\put(35,40){ \vector(1,0){15} }\put(35,11){ \line(0,1){28} }\put(33,25){ \makebox(0,0)[rc]{$d$} }\put(35,10){ \vector(1,2){15} }\put(35,8){ \makebox(0,0)[cc]{emitter} }\put(45,25){ \makebox(5,0)[cc]{$c \, t_B$} }\end{picture}[/math] Noting that [math]d = c \, t_A[/math], and from the Pythagorean theorem, [math]t_A[/math] and [math]t_B[/math] can be related:[math](c \, t_B)^2 = (c \, t_B)^2 + (v \, t_B)^2[/math]Dividing both sides of the equation by [math](c \, t_B)^2[/math] gives:[math]1 = \frac{(c \, t_A)^2}{(c \, t_B)^2} + \frac{(v \, t_B)^2}{(c \, t_B)^2}[/math]Removing common terms from the numerator and denominators of the fractions and rearranging, gives:[math]\frac{t_A^2}{t_B^2} = 1 - \frac{v^2}{c^2}[/math]Taking the square root of each side gives a form of the familiar Lorentz factor:[math]\frac{t_A}{t_B} = \sqrt{1 - \frac{v^2}{c^2}}[/math] We should be concerned about questions of simultaneity, since the actual events being measured are occurring at different distances from observer A and B. These concerns can be relieved by having the target reflect the signal back to the emitter, and by having A and the entire apparatus immediately emit another light signal and reverse direction at time [math]2t_A[/math], so that both A and B are the same distance from the emitter/target at the same instant. Quote Link to post Share on other sites

LaurieAG 34,630 Posted June 30, 2008 Report Share Posted June 30, 2008 Hi Craig, We should be concerned about questions of simultaneity, since the actual events being measured are occurring at different distances from observer A and B. These concerns can be relieved by having the target reflect the signal back to the emitter, and by having A and the entire apparatus immediately emit another light signal and reverse direction at time [math]2t_A[/math], so that both A and B are the same distance from the emitter/target at the same instant. What if we remove the problem of simultaneity by using a timing trigger that is equidistant from both points A and B? Quote Link to post Share on other sites

CraigD 398,736 Posted June 30, 2008 Report Share Posted June 30, 2008 Hi Laurie :weather_snowing:What if we remove the problem of simultaneity by using a timing trigger that is equidistant from both points A and B?What’s critical in my derivation is not that any specific event (eg: the light signal being emitted by the emitter, it being received by the target) occur at the same distance from A and B, but that the 2 events defining the entire duration be measured by each observer (the first light signal being emitted, the last one being received by the target) occur at the same position. If having A and B be the same distance from both events is helpful in visualizing them, by all means visualize them that way, but be mindful that both the beginning and ending event of the total measured durations need to be accounted for. What I attempted with my previous post is the simplest possible derivation of the special relativity’s time dilation, requiring only the postulate that c is constant, and that the square of the length of the longest side of a right triangle is equal to the sum of square of the lengths of the other two sides. My goal is to “demystify” this central feature of relativity. I think a lot of people who object to or deny the validity of relativity do so because they lack an intuitive, “hands on” feel for it due to lack of having seen it derived in an intuitive, simple way. I might have done better to omit the last paragraph, as it complicates the explanation, introducing the less simple concept of simultaneity, but though it better to quickly show that, by stringing together four of the described durations, simultaneity concerns can safely be ignored. Delving into simultaneity questions in special relativity leads rapidly to a host of mind-bending apparent paradoxes, such as the ladder paradox. Quote Link to post Share on other sites

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