Cap'n Refsmmat Posted June 21, 2011 Posted June 21, 2011 Different perspectives (frames of reference) make distance change? How is this different from measurements from different perspectives making distance change? Either way, do you believe that a near light speed frame of reference viewing (measuring) earth and getting half its well known and published diameter means that earth has actually "contracted" to half-size during that observation/measurement period? Say it ain't so! Or at least answer my above objections to such variations in earth diameter and AU length/distance. No, I do not. It does not contract and then return to normal shape once the observer has left. Consider a very long loaf of bread. Pretend it's a representation of two-dimensional space, where each slice of the bread is a snapshot of what happened in two-dimensional space at that time. If there's two raisins in the same slice at different places, they represent two events which occurred simultaneously but in different parts of space. Move to the next slice of bread and you see what happened a moment later, and so on. Now slice the bread diagonally instead of straight across. You're certainly still looking at the same loaf, but the distances between objects are different -- and in fact two raisins which were in the same slice previously are no longer both in your new slice. Your altered perspective has sliced reality so that you see different distances and different times between events. Note that while this analogy is useful, it is not necessarily technically perfect, and doesn't represent every detail of relativity. So, even though it takes light eight minutes to travel the distance, someone flying at near light speed but less than C, as required by physics, will find the distance (8 light minutes) and travel time (eight minutes) to "contract" to less than eight light minutes of length and less than 8 minutes of time? I get that his clock will not show 8 minutes for the journey... because his clock will have slowed down!Remarkable that the traveler going less than C can cover the standard one AU or 8 light minutes (length) in less time that light itself! Or maybe there ARE preferred frames of reference!... like at rest relative to the length being measured. Same for the ubiquitous "rod." The one in hand is a preferred frame of reference (measuring tape in the other hand) over the near-light-speed fly by shot at it. (Seems a reasonable hypothesis to me.) I thought you said you had studied relativity. Consider someone traveling at 0.99 times the speed of light. He flies past the Earth to the Sun and beyond, a distance of approximately 150,000,000 km according to an observer sitting on Earth. The traveler, of course, sees it as a distance of only 21,400,000 km, which takes him just over a minute to fly through. The observer sees it as a distance of 150,000,000 km, which takes the traveler over eight minutes to travel through. At no stage did the traveler travel faster than light. If you strapped a wristwatch to a photon, you'd find that it'd get there in no time at all (from its perspective).
owl Posted June 21, 2011 Author Posted June 21, 2011 (edited) Cap ‘n R: I thought you said you had studied relativity. I have. And, ontologically speaking, I find the relativity dictum that all distance is relative to measurement from various frames of reference “out of touch” with the reality that earth-sun distance does not actually lengthen or shorten with each variation in frame of reference from which it is observed/measure... to which I think you agreed in spite of your insistence that 'for a photon' or 'for the high speed traveler' the measured elapsed time and distance are drastically different from what I am calling the actual time and distance... That, contrary to relativity theory, there is a preferred frame of reference... at rest relative to that which is being measured. "Preferred" because of the "reality check" that there are no changes in global temperature or gravity with each high speed fly by "seeing" a way shorter distance between the bodies. Consider someone traveling at 0.99 times the speed of light. He flies past the Earth to the Sun and beyond, a distance of approximately 150,000,000 km according to an observer sitting on Earth. The traveler, of course, sees it as a distance of only 21,400,000 km, which takes him just over a minute to fly through. But the distance does not actually shorten from the standard one AU or about 150,000,000 km to 21,400,000km, and he does not travel the actual 150,000,000 km in “just over a minute” even though his clock and his own physical processes have slowed down so much that it recorded that only a minute or so had passed and his frame of reference measured the shorter distance. This is the ontology of the situation. His observation and measurement does not make the actual distance shorter (as “length contraction” would have it) or the actual elapsed time diminish from 8+ to 1+ minutes... just because that is what the traveler and his clock experience/measure. A slow-ticking clock (and slower physical aging process) at near C velocity does "make time slow down," as relativity (time dilation) would have it. And I have already belabored the argument that actual earth-sun distance does not "contract" for the obvious reasons given, even though "for the traveler," it looks that way. Please do not continue to mistake disagreement for ignorance of relativity. What's this... the thread is banished to the realm of pseudoscience because my ontology questions the reality of time dilation and length contraction. Very open-minded of Y'all! Edited June 21, 2011 by owl
swansont Posted June 21, 2011 Posted June 21, 2011 The problem with saying that the length does not actually lengthen or shorten is that you have adopted a reference frame that is "truth," i.e. a preferred reference frame. How do you justify this? Who is right, and why?
owl Posted June 21, 2011 Author Posted June 21, 2011 (edited) The problem with saying that the length does not actually lengthen or shorten is that you have adopted a reference frame that is "truth," i.e. a preferred reference frame. How do you justify this? Who is right, and why? Well, regarding length contraction, I asked the forum for any experimental evidence that the particle accelerator results on micro-subatomic scale apply to macro-scale lengths like earth diameter and earth-sun distance. Nothing but more references to high speed measurements showing shorter distance and elapsed travel time (time dilation) ignoring what the results would be in the "real world" if the AU were, say, 1/8 the "standard AU measure" from an at-rest frame. Same with the obvious "rod in the hand" comments in favor of at rest frame being the reality check on near-C fly-by measures which would, theoretically claim that the rod contracted to a fraction of the at-rest frame of measurement. Same with the ontology of time. No comment on the "clocks run slower at near-C" premise as a challenge to "time dilation"... with no consensus on what time is in the first place. (See my EDPP definition.) Is the "photon's" alleged perspective, no elapsed travel time, just as "correct" as the actual 8+ minutes required for sunlight to travel to earth? No, it is still an 8+ minute trip for light in the "real world." You (moderators/admin) treat science (relativity) like a dogmatic belief which tolerates no dissent. You guys even admitted that there is no confirmation of length contraction on everyday observable scale, yet you dogmatically insist on its Truth and ridicule me for arguing against time dilation and length contraction. Edit: Oopse! I just made a foolish mistake, thinking the thread had just been moved to "Speculations"... just edited for inappropriate remarks about that. I usually just go to 'my content' without thinking about what section this thread is in. Sorry. However, it should be moved to the philosophy section where ontology belongs as a part of the philosophy of science. (Would you please?) I'm still backtracking to reply to the opening comments in Cap 'n R's last post. Consider a very long loaf of bread. Pretend it's a representation of two-dimensional space, where each slice of the bread is a snapshot of what happened in two-dimensional space at that time. If there's two raisins in the same slice at different places, they represent two events which occurred simultaneously but in different parts of space. Move to the next slice of bread and you see what happened a moment later, and so on. I can't seem to "pretend" that a 3-D object is "a representation of two-dimensional space..." I see space as 3-D volume, while 2-D is confined to a plane. But I get the gist of the raisins in specific locations in the loaf if the loaf is a 3-D object representing space. Now slice the bread diagonally instead of straight across. You're certainly still looking at the same loaf, but the distances between objects are different -- and in fact two raisins which were in the same slice previously are no longer both in your new slice. Your altered perspective has sliced reality so that you see different distances and different times between events. You can slice the loaf any way you want and scatter the pieces around, and then claim that the distances between raisins has changed, which, of course it has with the loaf all over the table. But then we still have to apply the metaphor to objects (raisins) in space as observed in the real world. You can not slice up space, and move the pieces (and their contents) around, creating new distances between the objects, because space is the emptiness in which objects exist (as I see it.) Same with the earth to sun traveler you spoke of. You agreed that his perspective/measurements do not make earth move closer to sun, so how does the above illustration apply to what we can actually observe about objects in space? Note that while this analogy is useful, it is not necessarily technically perfect, and doesn't represent every detail of relativity. I honestly don't see how it is useful for the reasons stated above. Edited June 21, 2011 by owl -1
Cap'n Refsmmat Posted June 21, 2011 Posted June 21, 2011 You have misunderstood my metaphor. The loaf represents two-dimensional space; the third dimension of the loaf (the long dimension) is time. The slice on the far left represents what space was like far in the past; the slice on the far right represents space at the present. If I slice the loaf differently, I have not moved any of its contents. I have not moved any raisins. But suddenly two raisins which existed in the same slice now exist in different slices -- two events which occurred at the same time appear to have occurred at different times.
swansont Posted June 22, 2011 Posted June 22, 2011 Well, regarding length contraction, I asked the forum for any experimental evidence that the particle accelerator results on micro-subatomic scale apply to macro-scale lengths like earth diameter and earth-sun distance. Nothing but more references to high speed measurements showing shorter distance and elapsed travel time (time dilation) ignoring what the results would be in the "real world" if the AU were, say, 1/8 the "standard AU measure" from an at-rest frame. Same with the obvious "rod in the hand" comments in favor of at rest frame being the reality check on near-C fly-by measures which would, theoretically claim that the rod contracted to a fraction of the at-rest frame of measurement. Same with the ontology of time. No comment on the "clocks run slower at near-C" premise as a challenge to "time dilation"... with no consensus on what time is in the first place. (See my EDPP definition.) Is the "photon's" alleged perspective, no elapsed travel time, just as "correct" as the actual 8+ minutes required for sunlight to travel to earth? No, it is still an 8+ minute trip for light in the "real world." You never commented on whether you had experimentally verified that gravity exists in your living room. Insisting on a specific bit of evidence is a popular crackpot gambit, but it falls outside the realm of science. It allows one to raise the bar to the point where nothing need be accepted, because you can insist on evidence that cannot be obtained for technical reasons, regardless of the validity of the theory. You (moderators/admin) treat science (relativity) like a dogmatic belief which tolerates no dissent. 1) Calling theories "dogma" is another crackpot gambit and 2) Baloney Dogma, by definition, does not have evidence to support it. You guys even admitted that there is no confirmation of length contraction on everyday observable scale, yet you dogmatically insist on its Truth and ridicule me for arguing against time dilation and length contraction. Again, baloney. You have presented no evidence that contradicts relativity. Smearing science as dogma is an argument of distraction, as if people wouldn't notice that the emperor has no evidence to present.
Cap'n Refsmmat Posted June 22, 2011 Posted June 22, 2011 You (moderators/admin) treat science (relativity) like a dogmatic belief which tolerates no dissent. No, we require that dissent satisfy Speculations rule 1. You guys even admitted that there is no confirmation of length contraction on everyday observable scale, yet you dogmatically insist on its Truth and ridicule me for arguing against time dilation and length contraction. You have omitted a key word -- there is no direct experimental verification. The behavior of muon decay through the atmosphere provides indirect verification on scales as large as the height of the atmosphere. Also, length contraction "falls out" of the basic principles of relativity, like the invariant speed of light, and these principles have been incredibly well-tested from the microscopic scale to the astronomical scale. 2
md65536 Posted June 22, 2011 Posted June 22, 2011 That, contrary to relativity theory, there is a preferred frame of reference... at rest relative to that which is being measured. Isn't this just what "frames of reference" are in general? Things in an observer's inertial frame are at rest relative to the observer. Problems with this definition: - Every observer's frame is a preferred frame of reference, since every observer is at rest in their own frame. - How do you measure the distance between moving objects? For example, consider measuring the distance between 2 rockets moving away from each other. Where is the preferred frame, at rest relative to that which is being measured? I'm glad to see some specific ideas besides "SR is obviously wrong". 1
md65536 Posted June 22, 2011 Posted June 22, 2011 (edited) That, contrary to relativity theory, there is a preferred frame of reference... at rest relative to that which is being measured. Come to think of it, I think the technical name for that is "local frame of reference" (or perhaps "inertial frame of reference"?). You might say that every observer prefers their local frame of reference, but that is not the accepted meaning of preferred frame. Considering all frames, none are generally preferred over others. Edited June 22, 2011 by md65536
swansont Posted June 22, 2011 Posted June 22, 2011 Come to think of it, I think the technical name for that is "local frame of reference" (or perhaps "inertial frame of reference"?). Inertial simply means not accelerating, i.e. Newton's laws apply without any fictitious forces appearing.
owl Posted June 22, 2011 Author Posted June 22, 2011 (edited) The problem with saying that the length does not actually lengthen or shorten is that you have adopted a reference frame that is "truth," i.e. a preferred reference frame. How do you justify this? Who is right, and why? For openers, how I justified a preferred frame of reference in my reply post you dismissed as "baloney" without even the courtesy of being specific as to what made it baloney. (Argument by "smear" tactic is no argument.) Since Cap 'n R granted that earth does not move closer to sun when a traveler measures the distance as contracted to 1/8 AU and his travel time reduced to 1 minute (by his slowed-down clock) rather than the 8 it takes sunlight to reach earth, I thought this was a clear distinction between "actual" earth-sun distance and the near-C traveler's measurement of the distance. You never commented on whether you had experimentally verified that gravity exists in your living room. (Huh?) It seemed off-the-wall and irrelevant to the above argument. I obviously missed the significance of your point. My verification would be the same as Newton and his apple falling from a tree... what goes up will also come down in my living room. (??) Plus, I stick to the floor like everyone else rather than levitating. You have misunderstood my metaphor. The loaf represents two-dimensional space; the third dimension of the loaf (the long dimension) is time. The slice on the far left represents what space was like far in the past; the slice on the far right represents space at the present. If I slice the loaf differently, I have not moved any of its contents. I have not moved any raisins. But suddenly two raisins which existed in the same slice now exist in different slices -- two events which occurred at the same time appear to have occurred at different times. Yes, clearly I have not, as I already said, been able to "pretend" that a loaf of raisin bread is a 2-D object representing 3-D space. Maybe ontology is clouding my judgment, because, again, I don't see how the metaphor applies to what we call space and the stuff (raisins) in it... i.e., what we would "actually" be "slicing" and how that would alter the distances between objects. Also, as you know, the ontological status of "time" is the subject of this thread, and one camp in that argument asserts that it is simply event duration of physical processes rather having properties of its own as a component in a malleable medium, "spacetime." So making the length of the loaf represent time makes no more sense to me than making a loaf a bread a 2-D object, a plane with no thickness to "slice." Cap 'n R: You have omitted a key word -- there is no direct experimental verification. The behavior of muon decay through the atmosphere provides indirect verification on scales as large as the height of the atmosphere. Also, length contraction "falls out" of the basic principles of relativity, like the invariant speed of light, and these principles have been incredibly well-tested from the microscopic scale to the astronomical scale. As I understand it, incoming naturally occurring muons have a much longer "lifespan" than those observed in particle accelerators. (Am I right?) The difference is attributed to "time dilation." Correct? But if time is event duration of physical processes (my "EDPP"), and the physical process of decay for the former muons takes longer than their lab cousins, how does this verify "time" as an entity which expands ("dilates"), and how does this verify their distance traveled through the atmosphere as "contracted?" Finally, how come, if length contraction "falls out" from "incredibly well tested" (if indirect) experimental evidence, it can not be directly observed in contracted rods and AU lengths? You did agree, did you not, that earth does not "actually" move to 1/8 AU from the sun when so measured by that voyager traveling at near C? Edited June 22, 2011 by owl
swansont Posted June 22, 2011 Posted June 22, 2011 For openers, how I justified a preferred frame of reference in my reply post you dismissed as "baloney" without even the courtesy of being specific as to what made it baloney. (Argument by "smear" tactic is no argument.) Since Cap 'n R granted that earth does not move closer to sun when a traveler measures the distance as contracted to 1/8 AU and his travel time reduced to 1 minute (by his slowed-down clock) rather than the 8 it takes sunlight to reach earth, I thought this was a clear distinction between "actual" earth-sun distance and the near-C traveler's measurement of the distance. I think you need to reread the post. The arguments I called baloney were the ones where you claimed dogma and I explained why it was baloney, but I am glad you agree that argument by smear tactic is no argument. Does that mean you won't do it again? Cap'n granted that the earth does not move closer because is doesn't. To the traveler, the earth is closer. To describe it as moving closer implies a preferred frame, as if one observer sees "reality" and some other observation changes that reality, which is not what relativity entails. (Huh?) It seemed off-the-wall and irrelevant to the above argument. I obviously missed the significance of your point. My verification would be the same as Newton and his apple falling from a tree... what goes up will also come down in my living room. (??) Plus, I stick to the floor like everyone else rather than levitating. The reason I bring this up is that you don't seem to have a problem in accepting gravity existing in places where it has not actually been experimentally verified, and yet you attempt to hold relativity to a standard where you attempt to call results into question because some specified measurement has not been done. It's an inconsistent standard. As I understand it, incoming naturally occurring muons have a much longer "lifespan" than those observed in particle accelerators. (Am I right?) The difference is attributed to "time dilation." Correct? But if time is event duration of physical processes (my "EDPP"), and the physical process of decay for the former muons takes longer than their lab cousins, how does this verify "time" as an entity which expands ("dilates"), and how does this verify their distance traveled through the atmosphere as "contracted?" Finally, how come, if length contraction "falls out" from "incredibly well tested" (if indirect) experimental evidence, it can not be directly observed in contracted rods and AU lengths? You did agree, did you not, that earth does not "actually" move to 1/8 AU from the sun when so measured by that voyager traveling at near C? They live longer when moving fast. From d=vt, they travel further than they should, under Galilean rules. In their frame, the length must be contracted and the time dilated.
md65536 Posted June 22, 2011 Posted June 22, 2011 (edited) It seemed off-the-wall and irrelevant to the above argument. I obviously missed the significance of your point. My verification would be the same as Newton and his apple falling from a tree... what goes up will also come down in my living room. (??) Plus, I stick to the floor like everyone else rather than levitating. The relevance is that you accept that gravity applies beyond experimental evidence (eg. in your living room) but dismiss evidence of relativity beyond experiments. This view might make more sense if relativistic effects (like length contraction) were just parts of a theory devised to explain observations of high-energy particle experiments, which you've suggested that you believe. However, relativity is a theory devised to explain other observations... namely those of the speed of light, and measurements thereof in different forms over a century or two. Length contraction and time dilation are consequences of relativity and of the observations of light. The theory came before experimental observation of relativistic effects. Particle experiments support the theory; they did not spawn the theory. Maybe ontology is clouding my judgment Yes, I think this is true. I think it makes the most sense to consider only the properties of time that you can reason about (and do so precisely, ie. mathematically), and ignore everything else (because if you can't reason about it or test it, you can't validate it, and there would be no way to tell what is "true" from what is simply made up, or what is "cloudy"). For me a good ontological study would begin with what you can experimentally observe about time, and end with what you can logically deduce -- or perhaps a step further into interpretation(s). If ontology requires more (determining "what it is" when any potential answer can't be validated or evaluated), then I don't think ontology has scientific merit, besides being a source of imagination that can inspire new ideas. If ontology exceeds experimental validation, it is similar to me to visionary science fiction. But I think this is an aspect of philosophy in general, where it is good to think of ideas without limits, whether or not those ideas can be experimentally verified. Philosophy considers the meaning of things, and if you're trying to figure out something like time, that can definitely make things cloudy. Edited June 22, 2011 by md65536
owl Posted June 22, 2011 Author Posted June 22, 2011 (edited) I'll start here and then come back to more recent replies: swansont: ...and yet you attempt to hold relativity to a standard where you attempt to call results into question because some specified measurement has not been done. It's an inconsistent standard. Do you mean like challenging the leap from particle accelerator verification of length contraction (between end-points of subatomic particle locations at near lightspeed) to relativity's claim that a meter rod or an AU contracts when measured from a near 'C' fly-by frame of reference? Still seems like a reasonable challenge to me. Particle accelerator results are from quite an extreme arena of experimental measurement as micro-scale size and high velocity. Transference to large scale is not a given, as already acknowledged here by DrRocket. And, while on the subject, I will try to answer what I mean by at- rest frames of reference being "preferred" over those traveling near 'C' relative to what is being measured (replying to recent criticism from others in other posts.) We can all verify how long a meter stick is when holding it in our hands (at rest frame with the stick.) Seems obvious that this is the accurate standard of measure, which is one ten millionth of the earth surface distance from equator to pole (how it was derived.) But relativity claims that there is no preferred frame of reference, so that a near 'C' fly-by measurement of the same stick may see it as a tenth of a meter. My claim is that the latter is distorted by the extreme velocity frame from which it is measured, and that the former is the accurate measure. Further, I don't think that this argument makes me a "crackpot" as swansont has called me (or my argument, anyway.) As for the different muon lifespans as an argument for time dilation and length contraction... I hope that Cap 'n R will address my reply, as it was his example. You, swansont, said: They live longer when moving fast. From d=vt, they travel further than they should, under Galilean rules. In their frame, the length must be contracted and the time dilated. I don't dispute that "They live longer when moving fast." (I'm pretty sure that high speed space travelers do too.) But I will need to review what you call "Galilean rules" before a specific reply. Meanwhile, "living longer" does not mean that "time" has expanded around them during their journey or that the distance they traveled got shorter just because they went further than expected. (The ontological perspective.) I'll have to get back to further replies later. Edited June 22, 2011 by owl
swansont Posted June 23, 2011 Posted June 23, 2011 Do you mean like challenging the leap from particle accelerator verification of length contraction (between end-points of subatomic particle locations at near lightspeed) to relativity's claim that a meter rod or an AU contracts when measured from a near 'C' fly-by frame of reference? Still seems like a reasonable challenge to me. Particle accelerator results are from quite an extreme arena of experimental measurement as micro-scale size and high velocity. Transference to large scale is not a given, as already acknowledged here by DrRocket. I don't see where DrRocket said what you claimed. Especially since he said that the results of a planned experiment are unlikely to be a surprise. That sounds like the opposite of what you imply here. And, while on the subject, I will try to answer what I mean by at- rest frames of reference being "preferred" over those traveling near 'C' relative to what is being measured (replying to recent criticism from others in other posts.) We can all verify how long a meter stick is when holding it in our hands (at rest frame with the stick.) Seems obvious that this is the accurate standard of measure, which is one ten millionth of the earth surface distance from equator to pole (how it was derived.) But relativity claims that there is no preferred frame of reference, so that a near 'C' fly-by measurement of the same stick may see it as a tenth of a meter. My claim is that the latter is distorted by the extreme velocity frame from which it is measured, and that the former is the accurate measure. Further, I don't think that this argument makes me a "crackpot" as swansont has called me (or my argument, anyway.) That so-called distortion is the basis of relativity. You have to come up with some reason why a moving observer's measurement isn't valid, and how you know you're moving. And also address md65536's excellent point about how this applies to a distance between moving objects. If you will reread my earlier entry, you might note that this was not an argument I observed to be crackpottish in nature. (They were narrow insistence on a specific bit of evidence, and calling science dogma, i.e. I was calling attention to tactics rather than an argument, but I will note that playing the injured party to nonexistent attacks is also a dubious maneuver). This is merely a deficient understanding of relativity. As for the different muon lifespans as an argument for time dilation and length contraction... I hope that Cap 'n R will address my reply, as it was his example. I don't dispute that "They live longer when moving fast." (I'm pretty sure that high speed space travelers do too.) But I will need to review what you call "Galilean rules" before a specific reply. Meanwhile, "living longer" does not mean that "time" has expanded around them during their journey or that the distance they traveled got shorter just because they went further than expected. (The ontological perspective.) You need to come up with a mechanism for this, if you refuse to attribute it to time dilation and length contraction.
Cap'n Refsmmat Posted June 23, 2011 Posted June 23, 2011 Yes, clearly I have not, as I already said, been able to "pretend" that a loaf of raisin bread is a 2-D object representing 3-D space. Maybe ontology is clouding my judgment, because, again, I don't see how the metaphor applies to what we call space and the stuff (raisins) in it... i.e., what we would "actually" be "slicing" and how that would alter the distances between objects. It was either that or imagine a four-dimensional loaf that represents three-dimensional space, and usually that doesn't work out well. So, imagine two-dimensional space. Each instant of time in two-dimensional space is represented as a slice of the bread, and you can compile these instants together to get a "loaf." As I understand it, incoming naturally occurring muons have a much longer "lifespan" than those observed in particle accelerators. (Am I right?) The difference is attributed to "time dilation." Correct? But if time is event duration of physical processes (my "EDPP"), and the physical process of decay for the former muons takes longer than their lab cousins, how does this verify "time" as an entity which expands ("dilates"), and how does this verify their distance traveled through the atmosphere as "contracted?" Who said time is an entity? We know the muon's velocity, because we can measure it, and we know its average lifetime, which can be easily determined under any experimental condition you care to try. We also know what the muon decays into, and we can detect the particles it decays into. Hence if you can measure how many muons hit the upper atmosphere, how many reach the ground, and how many decay products reach the ground, you know how many muons decayed in the time it took to get from the upper atmosphere to the ground. And we know the muon velocity, because we measured it, so we know how long that takes. And for some reason we find that the muons decay much less than they should. This can be explained in several ways: From our perspective, what takes a long time (flying through the atmosphere) actually only takes a very short time for the muon, and so it doesn't have time to decay. From the muon's perspective, the atmosphere is just really thin, and it gets through faster. Something about muon decay changes when they're going fast through the atmosphere. The last option can be ruled out through laboratory experiment and through seeing that the same behavior applies to many other particles in many other different kinds of decays, and the simplest explanation is that speed changes the particle's perception of time. Finally, how come, if length contraction "falls out" from "incredibly well tested" (if indirect) experimental evidence, it can not be directly observed in contracted rods and AU lengths? You did agree, did you not, that earth does not "actually" move to 1/8 AU from the sun when so measured by that voyager traveling at near C? I did not agree to that. You would do well to re-read my previous posts more carefully. The Earth does not "move" when someone flies past. Anyone sitting on the Earth will not notice anything. The voyager at ludicrous speed will see the Earth as being close to the Sun. He will not see it "move"; it's been that way for as long as he's been flying fast. No force acts upon the Earth to "move" it or change its orbit; it's just the orbit is perceived differently by those in different reference frames.
owl Posted June 23, 2011 Author Posted June 23, 2011 Cap ‘n R, Please help me sort this out: Me: You did agree, did you not, that earth does not "actually" move to 1/8 AU from the sun when so measured by that voyager traveling at near C? You: I did not agree to that. You would do well to re-read my previous posts more carefully. The Earth does not "move" when someone flies past. Obviously, as I have been insisting. So this answers, for me, the question, “Who is right: the whole population of earth, the at- rest frame of reference at one end of the length/distance in question, measuring the standard one AU, or the voyager traveling at near ‘C’ and measuring the distance as 1/8 th AU? And I must repeat the “reality check” that if the distance was “actually” 1/8 AU, we would all fry as increased gravity crushes the earth. I am left wondering how anyone can claim that both measurements are equally correct just because of the relentless dictum of relativity that there are no preferred frames of reference. The same argument applies, of course, to the meter stick (in hand, at rest frame) staying one meter long even while the near ‘C’ fly-by guy measures it as a tenth (or an eighth) of a meter. As to your loaf of raisin bread: It was either that or imagine a four-dimensional loaf that represents three-dimensional space, and usually that doesn't work out well. So, imagine two-dimensional space. Each instant of time in two-dimensional space is represented as a slice of the bread, and you can compile these instants together to get a "loaf." Of course this all goes back to the long ago transition from Euclidean geometry and cosmology to non-Euclidean. First, a plane is two dimensional and volume (space or a loaf of bread) is three-dimensional. Imagining otherwise, for me is like imagining unicorns. I can do it, but that does not make them "actually" exist. Four dimensional space is nonsense to my (I think rational) mind. The three axes of 3-D space describe volume, and a fourth would be nonsense... no fourth dimension to space. Time, of course is a factor, usually called a “dimension,” but it just refers to “elapsed time” as objects move through 3-D space from A to B. I have frequently quoted from Kelley Ross’s paper on that subject. If you have not yet read it, you might find it interesting, as it speaks directly to these dimensional shifts in thinking and how/if they apply to “the real world.” You will find his The Ontology and Cosmology of Non-Euclidean Geometry at: http://www.friesian.com/curved-1.htm And while you are at it (as space and time are so intertwined in physics)... please also focus on Ross’s analysis of intrinsic vs extrinsic curvature as it relates to different *conceptual* manifolds. This is where non-Euclidean “curved space” came from in the first place, summarized briefly as follows: A curved line creates (requires) a plane; A curved surface (no longer a plane) creates (requires) volume; A supposed “curved volume or space” must, therefore create (require) a fourth spatial dimension. But now it becomes a mental concept without a referent, as we have run out of spatial dimensions with 3-D space. The ontology of such dimensions as in your loaf metaphor is, of course, a deep study... and I have often criticized "extra dimensions" beyond 3-D as metaphysical or imaginary... like the 7 extra ones in M-Theory (beyond 3-space + time.) What I like about ontology is that it questions things like "time" and "space" rather than taking them for granted as presented in textbooks... Like: "spacetime is curved by gravity"... assuming the components as taught in school ever since Minkowski and Einstein made the concept integral ingredients in relativity theory.
swansont Posted June 23, 2011 Posted June 23, 2011 Obviously, as I have been insisting. So this answers, for me, the question, “Who is right: the whole population of earth, the at- rest frame of reference at one end of the length/distance in question, measuring the standard one AU, or the voyager traveling at near ‘C’ and measuring the distance as 1/8 th AU? And I must repeat the “reality check” that if the distance was “actually” 1/8 AU, we would all fry as increased gravity crushes the earth. I am left wondering how anyone can claim that both measurements are equally correct just because of the relentless dictum of relativity that there are no preferred frames of reference. The same argument applies, of course, to the meter stick (in hand, at rest frame) staying one meter long even while the near ‘C’ fly-by guy measures it as a tenth (or an eighth) of a meter. Both observers are right. If you contend otherwise, what physics test can you apply that would determine who is correct?
md65536 Posted June 24, 2011 Posted June 24, 2011 The same argument applies, of course, to the meter stick (in hand, at rest frame) staying one meter long even while the near 'C' fly-by guy measures it as a tenth (or an eighth) of a meter. Out of curiosity, how would you apply your definitions to the following situation? You have 2 meter sticks, one in each hand. You move one of them and it is (imperceptibly) shorter than the other. Which stick is 1m, if they are different lengths? The one at rest I presume? Now suppose a friend is holding on to the other end of each stick. Suppose you pull on one stick (making it shorter to you due to length contraction), and your friend gets pulled along with the stick. The shorter moving stick for you, is the longer "at rest" stick for your friend. Which of you is correct?
owl Posted June 24, 2011 Author Posted June 24, 2011 swansont: Both observers are right. If you contend otherwise, what physics test can you apply that would determine who is correct? What am I missing here? If the 1/8 AU measurement were correct, earth would be about 19 million km from the sun rather than 150 million (one AU), the at -rest measurement, but it isn’t. Why does this fact require a new “physics test” to establish its validity? No astronomer in the world will scratch his head and wonder, "Is earth 19 million km from the sun or 150 million?" The latter is correct, and all astronomers know it without devising novel physics tests to prove it. md65536: Out of curiosity, how would you apply your definitions to the following situation? You have 2 meter sticks, one in each hand. You move one of them and it is (imperceptibly) shorter than the other. Which stick is 1m, if they are different lengths? The one at rest I presume? Now suppose a friend is holding on to the other end of each stick. Suppose you pull on one stick (making it shorter to you due to length contraction), and your friend gets pulled along with the stick. The shorter moving stick for you, is the longer "at rest" stick for your friend. Which of you is correct? There is no need to belabor the point that a moving frame of reference results in a shorter measurement than the at rest one. Not disputed. I repeat: The meter was derived as an earth- commensurate standard of measure, being one ten millionth of earth’s surface distance from equator to pole. I contend (and am certain) that neither the length of the meter nor the size of the earth are changed by measurements made from moving frames of reference. swansont: I don't see where DrRocket said what you claimed. Especially since he said that the results of a planned experiment are unlikely to be a surprise. That sounds like the opposite of what you imply here. DrRocket, post 106: However, as far as I know a direct measurement of length contraction has not been achieved. I will be as interested as anyone else if/when the results of the planned experiment are in. Anticipating such positive results do not count as support for length contraction in the macro-world. That so-called distortion is the basis of relativity. You have to come up with some reason why a moving observer's measurement isn't valid, and how you know you're moving. And also address md65536's excellent point about how this applies to a distance between moving objects. I am not disputing the effects of high speed frames of reference on measurement. I call it a distortion when such a measurement yields a small fraction of the known distance to the sun or earth diameter. It is a very good thing that relativity can make adjustments as needed for navigation, GPS accuracy, astronomical measurements, etc. You need to come up with a mechanism for this, if you refuse to attribute it to time dilation and length contraction. Ontologically speaking (as per thread topic), the well established evidence that "They live longer when moving fast” (both muons and probably space travelers) does not equate to “time dilates” or expands around them on their journey. Astronauts and muons aging more slowly and living longer and clocks ticking slower are physical processes that slow down with higher velocity. (No dispute.) This does not make time something that expands (which dilation means.) Likewise, traveling further than expected does not equate to length traveled contracting... both points being the primary focus of ontology in this thread. Ps; I'm still looking for clarification of this statement by Cap 'n R (post 107): Measurement does not make the distance change, but your perspective does. Your perspective makes the distance change? Again, how is that different from measurement. How is it that a 1/8 AU (19 or 21..?.. million km measurement or perspective (?) of sun-earth distance is not a distortion due to the relativistic effects of super high velocity?
Cap'n Refsmmat Posted June 24, 2011 Posted June 24, 2011 What am I missing here? If the 1/8 AU measurement were correct, earth would be about 19 million km from the sun rather than 150 million (one AU), the at -rest measurement, but it isn't. Why does this fact require a new "physics test" to establish its validity? No astronomer in the world will scratch his head and wonder, "Is earth 19 million km from the sun or 150 million?" The latter is correct, and all astronomers know it without devising novel physics tests to prove it. It is 19 million km from the Sun, according to the moving observer, and every astronomer with him would agree. The fact that there is not an absolute reference frame in relativity means there is no reason that two observers in different reference frames should agree on measurements of length or time. The universe just doesn't work that way. The Hafele-Keating experiment, GPS, and numerous other tests of relativity have shown this. Your perspective makes the distance change? Again, how is that different from measurement. How is it that a 1/8 AU (19 or 21..?.. million km measurement or perspective (?) of sun-earth distance is not a distortion due to the relativistic effects of super high velocity? I'll answer this with a question. Suppose the universe only contains me and a very large rock. There is absolutely nothing else for billions and billions of miles in every direction. Comfortable in my spacesuit, I watch the rock float past me. It appears to be moving at a constant speed, and I have no rockets or thrusters to change directions. Just floating along. Question: Which of the following three options is correct? I am moving and the large rock is stationary as I float past it. I am perfectly stationary and the large rock is floating past me. We're both moving. How would you decide?
md65536 Posted June 24, 2011 Posted June 24, 2011 Astronauts and muons aging more slowly and living longer and clocks ticking slower are physical processes that slow down with higher velocity. (No dispute.) This does not make time something that expands (which dilation means.) Interesting... you've nixed the accepted definition of time in favor of a new definition that includes only the concept of duration, but you're also saying that all physical process durations can change (ie. become longer durations, due to slower processes) independently of this new definition? In other words, your "EDPP" isn't "something" that can be changed, and remains defined for a relatively moving observer exactly as it does for an observer at rest, even if there are no unchanged durations to define it? Or did I get that wrong, and EDPP can dilate but time can't?
pantheory Posted June 25, 2011 Posted June 25, 2011 (edited) Swansont wrote: "Clocks "tick" at different rates in different inertial circumstances, as proven by many experiments. does not specifically address the issue of whether it's a mechanical issue of the clock. But this issue has not been ignored — different types of clocks have been tested, and they all show the time dilation effect. So we conclude that the timing changes are due to the effects of relativity. " I'm trying to get at the ontolology of "time," like, what is "it" besides event duration between designated instants? I know that our most sophisticated clocks show what has come to be known as "time dilation," but how is that different than, as above, the fact that they "keep time" differently (slow down or speed up) in different inertial environment Clocks keeping time at different rates is a different issue than asserting that "time itself" is an actual medium/entity which differs in each and every local inertia situation. I hope I'm making this distinction clearly. The ontology of time is a deep subject and relativity does not have a lock on time as a malleable medium in an of "itself," which clocks simply measure. Even the debate about a "global time structure" shed light on the assumption of relativity that local inertial frames of reference are the end all of the nature of time, space and the universe. BTW, I am not advocating that time is a "structure" but more like this: It is now everywhere (ongoing, perpetually), and time is an artifact of measurement, i.e., the duration of a given event between two designated instants. What say you? Respectfully, Owl I don't think that most concepts in Physics hit the mark concerning time. Such ideas such as time is a measurable period, or time is a continuum that lacks spatial dimensions -- do not inspire understandings of time in my opinion. More broadly there are primarily two schools in philosophy concerning understandings of time which inter-relate to some definitions of it in science: One is called "absolutist" theory which regards time as a kind of container within which the universe exists and changes take place, and believe that its existence and properties are independent of the physical universe. According to the rival "relationist" theory, time is nothing over and above change in the physical universe. Relationist theory is the only logical definition, according to my own model and definition. I think the O.P. (Owl) has a good understanding of what time is by saying "....the duration of a given event between two designated instants." I think this generally hits the nail on the head. Time is an interval of change according to my definition. The two key words accordingly are "change" and "interval." The concept involved would be: what would be the meaning of time if no changes of any kind took place. Time dilation occurs at both the macro and micro world levels as explained and calculated by Lorenz Transforms as in Special Relativity. A logical explanation I think is that time dilation is the result of apposing/ moving against the gravitational field which contains the entity experiencing time dilation as compared to objects which have no motion relative to their gravitational field, and which have the least time dilation. I believe time dilation is based upon the resistance of gravity which slows particle, atomic, and molecular decay and internal changes which can be measured relative to "stationary" material within the same gravitational position of the field. I also like his use of the word "instants" in his definition. I chose the words "time frames" (as in photographs) for the same meaning as his. Edited June 25, 2011 by pantheory
swansont Posted June 25, 2011 Posted June 25, 2011 swansont: What am I missing here? If the 1/8 AU measurement were correct, earth would be about 19 million km from the sun rather than 150 million (one AU), the at -rest measurement, but it isn’t. Why does this fact require a new “physics test” to establish its validity? No astronomer in the world will scratch his head and wonder, "Is earth 19 million km from the sun or 150 million?" The latter is correct, and all astronomers know it without devising novel physics tests to prove it. md65536: There is no need to belabor the point that a moving frame of reference results in a shorter measurement than the at rest one. Not disputed. I repeat: The meter was derived as an earth- commensurate standard of measure, being one ten millionth of earth’s surface distance from equator to pole. I contend (and am certain) that neither the length of the meter nor the size of the earth are changed by measurements made from moving frames of reference. If it's not disputed, then why do you continue to dispute it? Moving changes the measurement. This applies to the earth-sun distance. DrRocket, post 106: I will be as interested as anyone else if/when the results of the planned experiment are in. Anticipating such positive results do not count as support for length contraction in the macro-world. "Transference to large scale is not a given" is what you claimed. Essentially you have asserted that relativity fails on the macroscopic scale. That's not the same as saying the experiment hasn't been done. I'll point out again: gravity hasn't been experimentally tested in your living room. I am not disputing the effects of high speed frames of reference on measurement. I call it a distortion when such a measurement yields a small fraction of the known distance to the sun or earth diameter. It is a very good thing that relativity can make adjustments as needed for navigation, GPS accuracy, astronomical measurements, etc. You still have not presented a way to tell what is truth and what is "distortion."
owl Posted June 27, 2011 Author Posted June 27, 2011 Which of these statements is true: Earth is 19 million km from sun... or Earth is 150 million km from sun? Clearly the latter, as posted on all astronomy sites that give distances between bodies in our solar system. The near ‘C’ fly -by measures the former because of the relativity effect (distortion), but that does not mean earth is actually 19 million miles from the sun during the fly-by. As I said in post 107 "We would fry if we got that much closer to our sun. It simply is not true. Measurement does not make the distance change!” I asked, to no avail, how perspective makes the distance change, and if it changed to 1/8 AU (19 million km) why would we not fry? We don’t fry because the actual distance remains 150 million km from the sun and the former is a distortion due to the effects of relativity. Likewise Earth obviously does not shrink when a similar fly-by measures the diameter as one eight of what we measure from satellites at rest with earth. To claim that it does shrink or that the AU shrinks because relativity promotes length contraction and insists that there is no preferred frame of reference... so near ‘C’ fly by frames are just as accurate as at rest frames in either case is simply nonsense. Earth does not get closer to sun because relativity insists on length contraction and the dictum, "no preferred frame of reference." In post 141 Cap ‘n R said: The Earth does not "move" when someone flies past. Anyone sitting on the Earth will not notice anything. The voyager at ludicrous speed will see the Earth as being close to the Sun. He will not see it "move"; it's been that way for as long as he's been flying fast. No force acts upon the Earth to "move" it or change its orbit; it's just the orbit is perceived differently by those in different reference frames. So what he sees is distorted, i.e., earth is not actually closer to the sun just because that is how he sees it. Cap ;n R: It is 19 million km from the Sun, according to the moving observer, and every astronomer with him would agree. How would they account for the fact that they are not fried by such close proximity if the shorter measurement is not just a distortion. It remains a hot ball of fire not just a concept. You did not answer my question: (“Your perspective makes the distance change? Again, how is that different from measurement.”)... with your question. Question: Which of the following three options is correct? * I am moving and the large rock is stationary as I float past it. * I am perfectly stationary and the large rock is floating past me. * We're both moving. How would you decide? “ I agree that there is no way to tell.... unlike all the sophisticated measurements of Earth and our solar system from at rest frames relative to what is measured.... and the lack of shrinkage, as above with every supposed length contracted measure. As a matter of practical application, say for placing a satellite close to the sun, the preferred frame to measure the distance (and not let the satellite burn up) will not be the one that gets 19 million km for earth’s distance from it, but the standard as measured from earth (at rest at an end point of the distance measured.) md65536: Or did I get that wrong, and EDPP can dilate but time can't? Yes you got my meaning wrong. Event duration is from one instant to another, regardless of what arbitrary units of time we apply to this “elapsed time.” Physical processes in nature, on all scales and in clocks of all kinds proceed at various rates in different environments. When a clock slows down and we say “time dilates” it reifies time. The observable event is simply that a clock slows down, say at high speed or in altered gravitational field. My EDPP simply refers to time as the observed event duration of any physical process... which avoids “making something of time” as something that expands around objects as above. swansont: You still have not presented a way to tell what is truth and what is "distortion." Yes I have, quite a few times, and again above. If 19 million km were the correct distance from sun to earth (as above) we would all be fried. If earth’s diameter were 1589 km (1/8 actual diameter) rather than the precisely measured 12713 km (pole to pole)... well... it wouldn’t be Earth anymore, would it?
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