ydoaPs Posted December 31, 2011 Posted December 31, 2011 We all need an explanation of why/how clocks slow down at higher speeds and in higher gravitational fields. We could all use a good explanation of how gravity works too, without inventing more metaphysical metaphors.Yes, we do. You, however, refuse to read it. Realism as a philosophical perspective asserts that events in nature do not need to be clocked and compared between two frames of reference ‘clocking’ with different rates of “ticking.” Different rates of ticking do not measure different rates of "time passing." Relativity sorts that out fine for practical application, but duration of natural “real world” events does not depend on the variations in observers’ clocks. Sorry you can not comprehend the difference. Ok, let's take a time measurement from a frame at rest with the Earth. We will have identical observers with identical equipment at each location. One (A) measurement is taken in geostationary orbit, one (B) on top of Mount Everest, one © in the middle of a field in Iowa, one (D) at the bottom of the Marianas Trench, and one (E) taken in the center of the Earth's core. Which gives the "correct" measurement? Perhaps I could better comprehend it if it did not contain the glaring inconsistency that time is a duration, and a clock's tick is a calibrated duration, but clocks somehow do not measure time. Next you'll be telling me that a meter stick does not measure length. Based on owl's level of knowledge of philosophy he's displayed thusfar, that's not implausible.
owl Posted December 31, 2011 Author Posted December 31, 2011 Perhaps I could better comprehend it if it did not contain the glaring inconsistency that time is a duration, and a clock's tick is a calibrated duration, but clocks somehow do not measure time. Next you'll be telling me that a meter stick does not measure length.[/Quote] I said, Different rates of ticking do not measure different rates of "time passing." This would be false if I agreed that “time is that which clocks measure.” I don’t and have explained how that it is a tautology, not a definition of the "nature and properties of time” which it would have it were an entity with properties, which it isn’t. (De-reifying time, as it were.) I also said: “We all need an explanation of why/how clocks slow down at higher speeds and in higher gravitational fields. We could all use a good explanation of how gravity works too, without inventing more metaphysical metaphors.” Do you have an explanation for how “time passing more slowly” is detected by clocks, which then,” measuring time” as they are presumed to do, slow down accordingly? And how about that "explanation of how gravity works?” Oh, right, “mass curves ‘spacetime’.” Physics doesn't give a rat's ass how it works or what spacetime is. It's all in the math. And yet identical events have different durations if they are in different frames of reference. It takes more time for an event in a moving frame than for an identical event in the rest frame. How do you reconcile this with the assertion that nothing has happened to time? A fast moving clock ticks more slowly than one moving more slowly. (X 500 times repeated or so.) "It takes more what?" What is this mysterious thing, "time" which passes by a clock to be detected and measured? We can observe the variation in clocks. What do we observe when we declare that something has happened to time? You are blind to what the ontology of time seeks to understand about "it," or to debunk it as a reified entity. No, I think everyone gets it. You have an ideology and the world must conform to it. But someone who has taught the philosophy of science surely understands that science does not do this. Science does not proclaim something and look for evidence to support it, science looks at all the evidence and builds a model that best fits the evidence. Science discards models when they don't. You should re-read the paper you introduced on the "Bad Habits" of physics, including reification. I agree with his philosophy... if not his ten dimensional cosmology. And it is not just my ideology that time is an artifact of measurement, not 'something' in the real world, "passing" differently in an infinite number of locations and frames of reference. Your position is a prime example showing that philosophy is not relevant to science. Whether Earth changes shape with observation... or, alternatively, we can not know its "true shape" because it doesn't have one... is quite relevant to science. I have a hard time reconciling statements like these with your claimed expertise in matters connected to science. Of course you do. I taught philosophy of science. You disdain philosophy. Meanwhile you believe that the world is as we see it, from different, extreme frames of reference. So an Earth with a 1000 mile diameter, as seen from you- know- what frame is just as valid as a spherical world as seen from you-know -where. Up close and at rest is better for an accurate description of the "true shape of the Earth." But, of course, philosophically you don't believe that there is a "true shape of Earth," cuz it depends on how you look at it... a "lame" philosophy. And you believe that the distance between stars varies* (“length is not an invariant”) with how fast a frame of reference might be traveling between them. *(... or we can not know the 'actual' distance between them, depending as it does on observational frame... there is no 'actual distance.') Believe what you want. Older post follow up: me: If "three dimensional" was an important qualifier, please explain how other "dimensions" (besides time... yada yada) are verified as accurate descriptions of 'the world', not just mental models for math without referents.... Cap ‘n R: Science does not need to make this distinction; mental models for math which produceaccurate predictions are as close as we'll get to "accurate descriptions of 'the world'". What criteria do you use to judge an "accurate description"?[/Quote] You avoided the “please explain...” request. You like the non-Euclidean 4-D model but you will not explain to what a fourth dimension of space refers. Three-D covers space-as-volume. If the fourth is simply time... ok, things move around through 3-D space, and that “takes time. Is that what is meant by 4-D? Fine. As I’ve said many times before, experimental design always strives to minimize unknown variables. I say that measuring Earth from a near ‘c’ fly-by frame of reference introduces distortion, i.e., an Earth with an 8000 mile polar diameter and a 1000 mile equatorial diameter. Of course, the Lorenz formula will make the correction, but you don’t call it a correction. You say both descriptions are equally valid. No, Earth *is not squished,* even though it *might appear to be.* ydoaPs: Ok, let's take a time measurement from a frame at rest with the Earth. We will have identical observers with identical equipment at each location. One (A) measurement is taken in geostationary orbit, one (B) on top of Mount Everest, one © in the middle of a field in Iowa, one (D) at the bottom of the Marianas Trench, and one (E) taken in the center of the Earth's core. Which gives the "correct" measurement? This is tedious. We all know that they will "tick" at different rates. Over and over, I say that time is not 'something which clocks detect and measure...', so there is no "correct measurement of time" above. Get it yet? Never mind. It's ontology of time. Not your field of interest or expertise. And there is no use wasting my time debating your other points if you don't get this one.
ydoaPs Posted December 31, 2011 Posted December 31, 2011 This is tedious. We all know that they will "tick" at different rates. Over and over, I say that time is not 'something which clocks detect and measure...', so there is no "correct measurement of time" above. Get it yet? Never mind. It's ontology of time. Not your field of interest or expertise. And there is no use wasting my time debating your other points if you don't get this one. So you agree that duration (time) varies based on reference frame. Good. And there is no use wasting my time debating your other points if you don't get this one. So, now that you accept relativity, what happens to your distorted version of realism?
owl Posted December 31, 2011 Author Posted December 31, 2011 So you agree that duration (time) varies based on reference frame. Good.[/Quote] No. You read that wrong. We all know that your clocks will be ticking at different rates. “Duration” refers to elapsed time for physical processes to... proceed. I never said anything close to: " that duration (time) varies based on reference frame." Please quit putting words in my mouth and shoving them down my throat. So, now that you accept relativity, what happens to your distorted version of realism? This looks very much like what a 'jerk' might say, given that I accept some of the obvious contributions of relativity and reject others, like "length contraction, time dilation and curved 'spacetime.' But knowing the difference would require some level of discernment that it's not "all or nothing", black or white, with accepting relativity theory. This to the general conversation: About clocks "measuring time"... Amp-meters *measure* the power in the wire/system. Photographers often use "light meters" to *measure* light intensity for shutter settings. We can all think of many other "meters" that *measure* various things/forces, etc. So, if a clock were a "chronometer" it would *measure time* in the sense the physics argument here is presenting... minus 'what time is'... the ontological analysis. The latter is here-in above presented... yet again. Meters as measuring devises. Clocks don't *measure* anything. They just "tick"... at different rates in different environments/dynamics.
StringJunky Posted December 31, 2011 Posted December 31, 2011 (edited) Clocks don't *measure* anything. They just "tick"... at different rates in different environments/dynamics. What does a stopwatch do? We can measure out a certain amount of time with it and we can measure the duration between two events. It is exactly analogous to a ruler. Edited December 31, 2011 by StringJunky
swansont Posted December 31, 2011 Posted December 31, 2011 No. You read that wrong. We all know that your clocks will be ticking at different rates. “Duration” refers to elapsed time for physical processes to... proceed. I never said anything close to: " that duration (time) varies based on reference frame." Please quit putting words in my mouth and shoving them down my throat. They are your words, and they are inconsistent. The elapsed time for a physical process — using your words, above — is duration, which YOU have defined as time. So if I use a recurring physical process, I can measure time. In the real world we call this a clock. So how can it be that a clock does not measure time? Two physical processes, in different frames, will have different durations — you've stated this more than once. Shouldn't clocks have the same oscillation rate under realism anyway? An intrinsic, "real" frequency? 2
owl Posted December 31, 2011 Author Posted December 31, 2011 (edited) What does a stopwatch do? We can measure out a certain amount of time with it and we can measure the duration between two events. It is exactly analogous to a ruler. It ticks in between clicks of the switch while its operator observes an actual event. Then he can say how many ‘seconds’ (conventional time units) it took for the event. At no 'time' did "time" become anthing that might "dilate" or whatever as an entity would. Did you get that the "seconds" are just conventional units of 'time', not little pieces of a thing called "time." Just don't let the ruler travel near lightspeed it or it will shrink and a meter will become very short. What it was measuring, like the quadrant of Earth's surface will remain the same length however, no matter how short the meter rod appears to be. me: I never said anything close to: " that duration (time) varies based on referenceframe." They are your words, and they are inconsistent. The elapsed time for a physical process — using your words, above — is duration, which YOU have defined as time. So if I use a recurring physical process, I can measure time. In the real world we call this a clock. So how can it be that a clock does not measure time? Two physical processes, in different frames, will have different durations — you've stated this more than once.[/Quote] Which of his words quoted above were my words? If you use a recurring physical process, the function of a clock, you can assign conventional time units to a process you are observing simultaneously. If you were “measuring” a one mile running race with your stopwatch, the physical process of running the race will have taken four minutes or so (if it was a very fast run), and meanwhile your stopwatch will have been stopped after about four minutes of ticking. Sure, we can say that the watch “measured” the elapsed time of the race. As long as you don’t confuse the “physical processes” and believe that time is “something” other than the duration of the two processes, same "elapsed time" in this case. IOW, as long as you don’t reify time in the process. Then you could, like, reverse it or whatever and “go back in time.”... Or say that “it dilates” for muons and such.... making the atmosphere much thinner, “for a muon.”... the reciprocal of ‘time dilation’ once we get used to making time into something and just take it for granted. This requires more clarification: S: "Two physical processes, in different frames, will have different durations — you've stated this more than once." "Different frames" will make different clocks tick at different rates. Now, to the events the clocks are monitoring ("measuring" as you insist.) If you are clocking one Earth rotation from a very fast moving "frame of reference," your clock will have ticked fewer times that if you are clocking the same from the space station. The physical process of Earth completing one revolution will not have slowed down or speeded up just because the two clocks show different "elapsed times." Measurement does not create two different realities for an Earth rev, just two different "clocked times." You consistently confuse duration of events being timed (the race or the "Earth day") with differences in clock timing. Edit; missed a piece: Shouldn't clocks have the same oscillation rate under realism anyway? An intrinsic, "real" frequency? No way. We observe clocks ticking at different rates as above... and "measuring" a day to have more or less "elapsed time" according to different clocks in different frames. Realism insists that the elapsed time for an Earth rev does not change just because the clocks recorded more or less "time." Outta here 'til next year. Flip your calendars and synchronize your watches... All at sea level on the equator, preferably!... oh, and don't forget the timezones. "It IS now" at the 'same time' everywhere. Don't get confused by conventions and variable "measuring devises." Edited January 1, 2012 by owl
kitkat Posted January 1, 2012 Posted January 1, 2012 Philosophy is relevant to science in that this area has the freedom to interpret the scientific evidence that gives an opinion of another way of looking at the evidence that does not always agree with mainstream science community interepretation of the same evidence.
kitkat Posted January 1, 2012 Posted January 1, 2012 Philosophy is relevant to science in that this area has the freedom to interpret the scientific evidence that gives an opinion of another way of looking at the evidence that does not always agree with mainstream science community interepretation of the same evidence. Philosophy is relevant to science in that this area has the freedom to interpret the scientific evidence that gives an opinion of another way of looking at the evidence that does not always agree with mainstream science community interepretation of the same evidence.
DrRocket Posted January 1, 2012 Posted January 1, 2012 (edited) Yes, but philosophy usually asks questions that are impossible to prove experimentally. When you get into a very high level of abstraction experiments become impractical or impossible. Science itself isn't special when it comes to this, take string theory. The strings are so small that no experiment could ever prove that they exist and even if other predictions of the theory are proven, we would never really know that the string exists. The power, and acceptance, of a physical theory lie in the ability of the theory to make valid predictions. We don't have direct evidence of the existence of atoms (no has no one ever will see an atom). But quantum mechanics and the atomic hypothesis have produced a huge number of predictions of phenomena that have been borne out by experiment -- the entire field of chemistry for instance. String theory either will or will not make predictions of new physical phenomena that are validated by experiment or careful observation of nature. That is no different from any other new theory. Until it does, it is not really a physical theory, but only an avenue of research. Philosophers ask questions that are not only experimentally intractable, but in fact questions that are unanswerable in principle. Their hallmark is asking questions and providing no answers,but rather an exploration of the ramifications of the question itself. That is the crux of the difference between philosophy and science. If one placed all of the philosophers who have ever lived end to end, they would not reach........................................................... a conclusion. Philosophy is relevant to science in that this area has the freedom to interpret the scientific evidence that gives an opinion of another way of looking at the evidence that does not always agree with mainstream science community interepretation of the same evidence. You have just equated philosophy with pseudoscience. I do not agree with that characterization. It does a disservice to both philosophy and science. Edited January 1, 2012 by DrRocket
swansont Posted January 1, 2012 Posted January 1, 2012 If you use a recurring physical process, the function of a clock, you can assign conventional time units to a process you are observing simultaneously. If you were “measuring” a one mile running race with your stopwatch, the physical process of running the race will have taken four minutes or so (if it was a very fast run), and meanwhile your stopwatch will have been stopped after about four minutes of ticking. Sure, we can say that the watch “measured” the elapsed time of the race. As long as you don’t confuse the “physical processes” and believe that time is “something” other than the duration of the two processes, same "elapsed time" in this case. Can I use a watch to measure another watch? An identical one? They are identical processes, so they must agree, right? "Different frames" will make different clocks tick at different rates. I'm curious as to what part of realism predicts this will happen. Another hundred or so times I have said that time is *duration* of physical processes. I'm not going to bother looking up the hundred, since you acknowledge this. An oscillation is a physical process; it has a duration. Thus, logically, there is a time associated with the oscillation. The oscillation changes depending on the frame of reference. It slows down when the oscillator is moving. The duration of the physical event is longer. By your definition, the elapsed time is longer. 1
tar Posted January 2, 2012 Posted January 2, 2012 (edited) Owl, We both agree the Earth is only rotating in "one" direction. My question is how would you, Owl, describe that direction. I am trying to force you to make a "realistic" observation. You cannot just say "it is going in the direction it is going". Describe that direction. Is that direction "relative" to something else? Is the description "how it would look" from a certain perspective? How, (philosophically) can you say something about something, without saying something about it? And philosophically, if it has been known by more than just a several great minds, that knowing the thing in itself is not what we are generally capable of doing, why would you talk negatively about any scientist that agreed that they, being human, do not have access to the "thing in itself"? That YOU have access to this "thing in itself" is COMPLETELY idealistic in my book. Say something about the direction in which the Earth rotates. Anything at all. Regards, TAR2 Edited January 2, 2012 by tar 1
tar Posted January 2, 2012 Posted January 2, 2012 (edited) Owl, You have an insight that you believe I have not "gotten to" yet. This is very possibly true. It happens all the time. People have been around for 10s of thousands of years having them. Regular people have them, special people have them. And people like to share their insights. Bring those that have not had their's up to speed. And people like to get up to speed with those that have had "further" insights. But guess what. They are insights. That is, internally generated. Do they have relevance to the "thing as it is"? Obviously. That is what the insights are about. And people, take me for instance, can have insights, anew, that someone else, somewhere else, and sometime else, have already had. Just bear in mind, that this can also be the case for Owls and TARs. You may have an insight you are attempting to bring me to, that I have already had. And I may be attempting to bring you to an insight that you have already had. But in general, a true insight can be had by all. And if you can not describe it, point people to it, and show others where it comes up in reality, it is more likely that it exists in your mind alone, and not out where others can see it too. Such is my determination about the "thing in itself". If I imagine I can contain it, I am wrong. If I imagine I can contain it in a manner I can describe to you, and you can similarly contain it, then we may be talking about the same "thing as it is". Regards, TAR2 Consider the "duration" between the ball dropping at Time's Square in NYC marking the moment between 2010 and 2011, and the moment the ball hit the bottom of the pole marking the dividing line between 2011 and 2012. What duration is that year? The Earth made it one time around the Sun? In reference to what? The Sun is not even in the same place it was a year ago. It has proceeded around the center of the Milky Way. The path of the Earth in the last year, when viewed from a perspective high atop the Milky Way is not an elipse. The path Time's Square took in the duration, is even more not like an elipse, what with all the epicycles as the Earth rotates on its axis, and the fact that the plane of the Solar System is not parallel with the plane of the Galaxy and all. We, as a solar system, as an Earth and as a Time's square are none of us, in the same place we were last year, "at this time". and what if the Milky Way "moved"? Edited January 2, 2012 by tar
owl Posted January 2, 2012 Author Posted January 2, 2012 (edited) Can I use a watch to measure another watch? An identical one? They are identical processes, so they must agree, right?[/Quote] Are they in different ‘gravity fields’ (altitudes, etc.) or moving at different velocities? If so they will differ in ticking rates, as has been agreed over and over.... and over. me: "Different frames" will make different clocks tick at different rates." You: I'm curious as to what part of realism predicts this will happen. The part which acknowledges empirical science including observation of physical processes. It happens every time we put up another satellite with a clock in it. We can safely predict that it will continue to happen.* That, however, does not make ‘time” into something that varies. (The anti-reification philosophy of time.) The latter entails ontology of time, however. Not something you understand or care about. *Note: I don't know the dynamics/mechanics... the "how that works" or what it is about gravity and velocity that slows down clocks. If you do, please enlighten us all. Btw,... "Clocks detect time and it slows down because of relativity'... is not an answer. (That is reification of time.) An oscillation is a physical process; it has a duration. Thus, logically, there is a time associated with the oscillation. The oscillation changes depending on the frame of reference. It slows down when the oscillator is moving. The duration of the physical event is longer. By your definition, the elapsed time is longer. Agreed, yet again. Never have I argued against the concept of elapsed time as things move, whether oscillating (clocks) or objects moving through space from A to B. See the anti-reification stipulation (...) above. Owl, We both agree the Earth is only rotating in "one" direction. My question is how would you, Owl, describe that direction. I am trying to force you to make a "realistic" observation. You cannot just say "it is going in the direction it is going". Describe that direction. Is that direction "relative" to something else? Is the description "how it would look" from a certain perspective? ..... Say something about the direction in which the Earth rotates. Anything at all. Regards, TAR2 I already have as best I can, repeatedly, like, many times, addressed the direction of Earth’s rotation. Last time: It rotates *counter-clockwise as seen from above the North Pole* and it rotates clockwise as seen from above the South Pole.* It is important to understand that the above differences in *direction of rotation as seen from opposite poles* does **not** mean that Earth changes direction of rotation. Realism says that point of view or frame of reference does not change the physical nature of whatever is being observed, even though things will look different from different perspectives/frames of reference. I hope this clears it up, because I really can’t think of a better way to explain it. Edited January 2, 2012 by owl
swansont Posted January 2, 2012 Posted January 2, 2012 Agreed, yet again. Never have I argued against the concept of elapsed time as things move, whether oscillating (clocks) or objects moving through space from A to B. See the anti-reification stipulation (...) above. So you agree that the elapsed time is different in different frames. And yet you lambasted ydoaPs for saying that you agree with this. For this is exactly what special relativity says. Your problem seems to be with the pedagogy. Now, does a meter stick measure length?
owl Posted January 3, 2012 Author Posted January 3, 2012 So you agree that the elapsed time is different in different frames. And yet you lambasted ydoaPs for saying that you agree with this. For this is exactly what special relativity says. Your problem seems to be with the pedagogy. Now, does a meter stick measure length? Maybe if i just keep repeating.... This is tedious. We all know that they will "tick" at different rates. Over and over, I say that time is not 'something which clocks detect and measure...' "Different frames" will make different clocks tick at different rates. If you are clocking one Earth rotation from a very fast moving "frame of reference," your clock will have ticked fewer times that if you are clocking the same from the space station. The physical process of Earth completing one revolution will not have slowed down or sped up just because the two clocks show different "elapsed times." We observe clocks ticking at different rates as above... and "measuring" a day to have more or less "elapsed time" according to different clocks in different frames. Realism insists that the elapsed time for an Earth rev does not change just because the clocks recorded more or less "time." Yes, There are ten million meters from equator to pole on the surface of the Earth. If you fly by Earth at near 'c' and measure the quadrant to be one million meters, however, that measurement will be an error. Likewise if you "see" the meter rod itself to be ten or fifteen centimeters, that too will be wrong. Different frames of reference will not cause a solid meter rod to shrink, nor the Earth's diameter. This is realism. Earth stays as is, no matter how you look at it. Often repeated measurements verify Earth's size and shape and elapsed time for a rotation and an orbit. SR can not re-invent the world and the cosmos to fit its theories. I am done with this.
ydoaPs Posted January 3, 2012 Posted January 3, 2012 Maybe if i just keep repeating.... Yes, There are ten million meters from equator to pole on the surface of the Earth. If you fly by Earth at near 'c' and measure the quadrant to be one million meters, however, that measurement will be an error. Likewise if you "see" the meter rod itself to be ten or fifteen centimeters, that too will be wrong. Different frames of reference will not cause a solid meter rod to shrink, nor the Earth's diameter. This is realism. Earth stays as is, no matter how you look at it. Often repeated measurements verify Earth's size and shape and elapsed time for a rotation and an orbit. SR can not re-invent the world and the cosmos to fit its theories. I am done with this. Is that "correct" measurement the one from geostationary orbit, the one from the top of Everest, the one from sea level, the one from the bottom of Marianas Trench, or the one from the centre of the core?
swansont Posted January 4, 2012 Posted January 4, 2012 I assume your yes is to the question I asked. How does a meter stick measure length?
tar Posted January 4, 2012 Posted January 4, 2012 I already have as best I can, repeatedly, like, many times, addressed the direction of Earth’s rotation. Last time: It rotates *counter-clockwise as seen from above the North Pole* and it rotates clockwise as seen from above the South Pole.* It is important to understand that the above differences in *direction of rotation as seen from opposite poles* does **not** mean that Earth changes direction of rotation. Realism says that point of view or frame of reference does not change the physical nature of whatever is being observed, even though things will look different from different perspectives/frames of reference. I hope this clears it up, because I really can’t think of a better way to explain it. Owl, OK fine. But you are giving two answers for one rotation. This is no different from what relativity is saying about an Earth near C flyby. Earth has one real shape that must be measured differently according to the relative velocity of the measurer. As surely as the single rotation will be viewed as clockwise from above the South Pole, counterclockwise from above the North pole, left to right if viewed from the equator with your head up (like the North Pole) and right to left if you are above the equator, but upside down (head up like the South Pole). To say this is to not expect that the universe flips every time you stand on your head. Neither do the equations of space time expect anything to actually change their one shape. Regards, TAR2
owl Posted January 4, 2012 Author Posted January 4, 2012 (edited) Is that "correct" measurement the one from geostationary orbit, the one from the top of Everest, the one from sea level, the one from the bottom of Marianas Trench, or the one from the centre of the core? I said that I am done with this, but I changed my mind. I suggest you brush up on Earth science by a search for "measuring earth" sites and links. There are a lot of them and they all agree on the size and shape of Earth. For some reason, none of the measurements were based on a very high speed fly-by of Earth. Owl, OK fine. But you are giving two answers for one rotation. This is no different from what relativity is saying about an Earth near C flyby. Earth has one real shape that must be measured differently according to the relative velocity of the measurer. As surely as the single rotation will be viewed as clockwise from above the South Pole, counterclockwise from above the North pole, left to right if viewed from the equator with your head up (like the North Pole) and right to left if you are above the equator, but upside down (head up like the South Pole). To say this is to not expect that the universe flips every time you stand on your head. Neither do the equations of space time expect anything to actually change their one shape. Regards, TAR2 You seem to be still missing my main point, which I had italicized in the post you quoted. One more time: Realism says that point of view or frame of reference does not change the physical nature of whatever is being observed, even though things will look different from different perspectives/frames of reference. My continuing argument here with advocates of length contraction and time dilation is based on their claim that a very oblate spheroid is an equally valid description of Earth with Earth science's nearly spherical description. Their claim is based on the SR dictum that there are no preferred frames of reference, ergo, a flattened (appearing) Earth is just as valid. The same argument applies to "time dilation." If one Earth rotation on its axis is "timed" or "clocked" from a high speed frame of reference, the clock will slow down and give a "clocked time" for "a day" substantially less than that given by a clock on the surface for one rotation. (I have advocated that our best clocks placed at sea level on the equator would be the best way to establish a standardized "day." A far away star would be the point of reference for one of those, say the master clock.) Edit: Btw, I recently made the point (as per "measuring time") that clocks just tick... at different rates with gravity and velocity. So relativity does a good job of 'correcting' for all those differences and making GPS, among many other things, work quite precisely. But clocks do not "measure time" in the same sense that amp meters measure electrical power of light meters measure light intensity. So confuses arises as if clocks measured something like light intensity or electric power. This reifiys time by "making something of it." So if "time is that which clocks measure" and they "measure" different elapsed times for an Earth rotation, the confusion lies in different lengths for "a day" as measured by different clocks, as above. But in the "real world", the elapsed time for one Earth rotation does not change with those different "measurements." I hope this clears up my points about length contraction and time dilation, because the above is the best I can do, and I have hammered on it in many threads over quite some 'time' (that which elapsed since my first argument.) Edited January 4, 2012 by owl
swansont Posted January 4, 2012 Posted January 4, 2012 Edit: Btw, I recently made the point (as per "measuring time") that clocks just tick... at different rates with gravity and velocity. So relativity does a good job of 'correcting' for all those differences and making GPS, among many other things, work quite precisely. But clocks do not "measure time" in the same sense that amp meters measure electrical power of light meters measure light intensity. So confuses arises as if clocks measured something like light intensity or electric power. This reifiys time by "making something of it." How does an ammeter or light meter or meter stick measure their respective quantities?
mississippichem Posted January 4, 2012 Posted January 4, 2012 owl, So is Earth orbiting the sun clockwise or counter-clockwise? Realism demands a non-frame dependent answer as it does for the diameter of the earth. Answer the question and stop repeating yourself. Im applying the same standards to realism that you have required of special relativity. So don't claim that I'm missing the point. Pony up and make a definitive statement.
owl Posted January 4, 2012 Author Posted January 4, 2012 How does an ammeter or light meter or meter stick measure their respective quantities? The meters detect power and light, respectively. A meter stick is laid end to end over the distance measured and multiplied by how many it took to go the distance (or what fraction of the stick a shorter distance occupied.) All quite obvious. So what was your point? What do you think clocks detect? Are they "chronometers" in the same sense as the above two meters detect power and light, i.e., is "time" a detectable entity/force as they are? No.
swansont Posted January 4, 2012 Posted January 4, 2012 The meters detect power and light, respectively. It's OK to say that you don't know the details. I'd venture to guess that most people don't; not really a fair question on my part. We'll stick to the ruler/meter stick, since that's a much more common instrument. A meter stick is laid end to end over the distance measured and multiplied by how many it took to go the distance (or what fraction of the stick a shorter distance occupied.) All quite obvious. So what was your point? So we have an item that is 60 cm long, and we put the meter stick next to it and see that the difference in the endpoints is 60 cm. The meter stick is simply a calibrated length with which me may compare things. That's what we mean by a measurement: a quantitative comparison with some standard. I notice you have not raised any objections to any of these measurements (current, intensity, length) reifying the quantities they measure. A clock is simply a device that has been calibrated for a particular duration. It is, in that basic concept, no different than a meter stick: a calibrated length of time with which me may compare things. So I don't understand why you say that a clock does not measure elapsed time. What do you think clocks detect? Are they "chronometers" in the same sense as the above two meters detect power and light, i.e., is "time" a detectable entity/force as they are? No. This is more subtle than you might think. Detect and measure are not synonymous. I have an ammeter that measures current, but what it detects is magnetic field. A power meter that measure power but detects the change in resistance from a temperature change. A thermometer that measures temperature but detects photons. I don't think anyone here has claimed that a clock detects time (that would be reifying it, no?). A clock measures time, but what it detects is oscillations, which have a well-specified duration. 1
ydoaPs Posted January 4, 2012 Posted January 4, 2012 I said that I am done with this, but I changed my mind. I suggest you brush up on Earth science by a search for "measuring earth" sites and links. There are a lot of them and they all agree on the size and shape of Earth. For some reason, none of the measurements were based on a very high speed fly-by of Earth. Different altitudes give different readings. Which one is correct?
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