geordief Posted September 15, 2016 Posted September 15, 2016 A very simple question but one that is quite likely the product of a garbled thought process (so apologies in advance): Is it possible to conceive of motion without the concept of time (either time per se or time as measured by a clock and a signal) ? Are Motion and Time joined at the hip? PS I am only posting in Philosophy because I fear my question may be too insubstantial for the Relativity Forum where I intended to put it 1
ydoaPs Posted September 15, 2016 Posted September 15, 2016 There are atemporal models, but they obviously don't conceive of motion as the same object in different places at different times. Rovelli's evolving constants model is particularly intriguing. 2
Strange Posted September 15, 2016 Posted September 15, 2016 I don't think it is possible to have motion without time. But there can be time without motion.
DrKrettin Posted September 15, 2016 Posted September 15, 2016 I don't think it is possible to have motion without time. But there can be time without motion. OK - I'll bite. Can you explain how there can be time without motion?
geordief Posted September 15, 2016 Author Posted September 15, 2016 (edited) If we accept the concept of a time without motion does that mean we must disregard (as inconsistent) the idea that time can "stop" as is claimed in various scenarios (I think heat death is one)? Actually I may need to apologize to Strange as I see I may be just going over old recent ground on another forum where I asked almost the same question (my memory is to blame ) I think the process of decay in an atomic clock was there adduced as an instance of time passing without motion. Edited September 15, 2016 by geordief
studiot Posted September 15, 2016 Posted September 15, 2016 A very simple question but one that is quite likely the product of a garbled thought process (so apologies in advance): Is it possible to conceive of motion without the concept of time (either time per se or time as measured by a clock and a signal) ? Are Motion and Time joined at the hip? PS I am only posting in Philosophy because I fear my question may be too insubstantial for the Relativity Forum where I intended to put it "PS I am only posting in Philosophy because I fear my question may be too insubstantial for the Relativity Forum where I intended to put it" Good question and good place to put it since philosophy is the place for garbled thought processes. But it is not a stupid question so +1 In particular "Are Motion and Time joined at the hip?" No they are not. It is possible to separate them. But I don't think you were expecting this sort of answer. The wave equation is officially an equation of motion - wave motion. There are two forms of solution to the wave equation, called travelling waves and stationary waves. For travelling waves distance and time are indeed joined at the hip. But for stationary waves they have been separated and solutions which contains only distance are available. That is why we say the stationary or standing wave is time independent, (Note this is a less garbled phrase), even though if we look at standing waves on say a stretched string the string is actually in motion.
Strange Posted September 15, 2016 Posted September 15, 2016 (edited) OK - I'll bite. Can you explain how there can be time without motion? As someone said in another thread, physicists play with toy models of the universe including some with zero matter and energy (but still based on the GR model of space-time). As such, there is time but no motion (nothing to move). Edit: actually, it was another forum, not just another thread. Edited September 15, 2016 by Strange
michel123456 Posted September 15, 2016 Posted September 15, 2016 There are atemporal models, but they obviously don't conceive of motion as the same object in different places at different times. Rovelli's evolving constants model is particularly intriguing. +1 for Rovelli I don't see very much on the web for Rovelli, this https://en.wikipedia.org/wiki/Carlo_Rovelli and this https://en.wikipedia.org/wiki/Thermal_time_hypothesis what is it all about?
ydoaPs Posted September 15, 2016 Posted September 15, 2016 +1 for Rovelli I don't see very much on the web for Rovelli, this https://en.wikipedia.org/wiki/Carlo_Rovelli and this https://en.wikipedia.org/wiki/Thermal_time_hypothesis what is it all about? He's pretty big in the Loop Quantum Gravity world. A lot of his stuff is on ArXiV.
geordief Posted September 17, 2016 Author Posted September 17, 2016 (edited) As it is my OP perhaps I can go a bit "off piste" ? (thanks for the Rovelli reference-i will try and give it a look). I was wondering is there any significance to the observation that motion is actually the natural prevailing order of things and that "stationaryism" can be viewed as a limit ? (an idealized state ?) I feel clearly it justifies ** the use of a Minkowski geometry rather than a Euclidean. Are there any other fundamental consequences that might flow from an acceptance that a stationary frame of reference is an idealized concept? **I realize that it is also justified by experimental verification.... Edited September 17, 2016 by geordief
Tim88 Posted September 20, 2016 Posted September 20, 2016 A very simple question but one that is quite likely the product of a garbled thought process (so apologies in advance): Is it possible to conceive of motion without the concept of time (either time per se or time as measured by a clock and a signal) ? Are Motion and Time joined at the hip? PS I am only posting in Philosophy because I fear my question may be too insubstantial for the Relativity Forum where I intended to put it I would say so. Time is a measure of the progress of physical processes, and that implies motion. Concerning stationary waves, they are fundamentally built up from traveling waves - at least that is what I learned in physics classes a long time ago. Assuming that the theory is correct, without time traveling waves cannot be created - even if one neglects that physical fact in the mathematical equation.
Strange Posted September 20, 2016 Posted September 20, 2016 I am amazed how often the same thread comes up with exactly the same arguments on both sides. Time is a measure of the progress of physical processes, and that implies motion. Physical processes are how we measure time. Time is not defined by that. And not all physical processes involve motion. 1
studiot Posted September 20, 2016 Posted September 20, 2016 I am amazed how often the same thread comes up with exactly the same arguments on both sides. Physical processes are how we measure time. Time is not defined by that. And not all physical processes involve motion. +1 on both counts. tim88 I would say so. Time is a measure of the progress of physical processes, and that implies motion. Concerning stationary waves, they are fundamentally built up from traveling waves - at least that is what I learned in physics classes a long time ago. Assuming that the theory is correct, without time traveling waves cannot be created - even if one neglects that physical fact in the mathematical equation. A wave is a solution to the wave equation. Are you suggesting that the following equation y = A sin(bx) does not satisfy the wave equation?
swansont Posted September 20, 2016 Posted September 20, 2016 Physical processes are how we measure time. Time is not defined by that. And not all physical processes involve motion. Indeed. In a run-of-the-mill atomic clock the oscillation is from a superposition of atomic states. But there's no motion there; the oscillation is a quantum mechanical construct — a vector on the Bloch sphere. IOW, it's a description of the system that has the oscillation. The actual system is just half of the atoms in one state and half in the other. They could be just sitting there (and in ion trap clocks, they basically are) Any physical motion is incidental to the operation of the clock. 1
Tim88 Posted September 20, 2016 Posted September 20, 2016 [..] A wave is a solution to the wave equation. Are you suggesting that the following equation y = A sin(bx) does not satisfy the wave equation? Sorry, I cannot understand how you could think so from my clarification that "stationary waves [..] are fundamentally built up from traveling waves" and "without time traveling waves cannot be created - even if one neglects that physical fact in the mathematical equation". Thus I have to ask in turn: are you suggesting that you can create a standing wave without time??
studiot Posted September 20, 2016 Posted September 20, 2016 Sorry, I cannot understand how you could think so from my clarification that "stationary waves [..] are fundamentally built up from traveling waves" and "without time traveling waves cannot be created - even if one neglects that physical fact in the mathematical equation". Thus I have to ask in turn: are you suggesting that you can create a standing wave without time?? I didn't suggest, I stated an equation which is the equation of a wave which is independent of time. In other words time does not appear in the equation which connects x and y only. Please note I did not state this to be either a travelling wave or a standing wave. We are talking mathematics here so I do not understand the relevance of your reference to the simplistic high school explanation used to introduce standing waves. We do not create or build waves in mathematics. The solutions must exist for all x, y and t. This obviates creation or building as there can be no start or end points. Please also remember that geordief asked if it was possible to separate space and time in regard to wave motion and the answer is a most emphatic yes, but only in the right circumstances. I think my post#6 was clear enough to establish the context of my remarks. But feel free to quibble away. And also please answer my question Is my stated equation a solution to the wave equation and what is its dependence on time (which does not appear in it)?
geordief Posted September 20, 2016 Author Posted September 20, 2016 (edited) My OP is only concerned with processes that occur in nature and not with mathematical abstractions which attempt to model them ** The equation y = A sin(bx) does not describe any such process ,does it ? Is it not necessary to introduce the time parameter in order to model something which actually exists in nature.? Facetiously we cannot feed our bodies with mathematical equations. In post #10 I wondered if "stationaryism" was an idealized concept at odds with the way the universe actually works (continuous motion). . If we accept this concept then does this continuous motion imply time ? (locally ,globally?) As I said I am excluding purely mathematical representations which do not model anything existing as we observe them externally to our thought processes.(which is how I am seeing this y = A sin(bx) equation) A standing wave is not described by this equation because a standing wave is time limited (the string will eventually dissipate and the "standing" wave will move since ,in the "real" world it is not stationary but moving wrt any observer ) **I hope this is a valid distinction or do we have to say that mathematical models are a subset of the set of natural processes we observe around us?. Edited September 20, 2016 by geordief
studiot Posted September 20, 2016 Posted September 20, 2016 My OP is only concerned with processes that occur in nature and not with mathematical abstractions which attempt to model them ** The equation y = A sin(bx) does not describe any such process ,does it ? Is it not necessary to introduce the time parameter in order to model something which actually exists in nature.? Facetiously we cannot feed our bodies with mathematical equations. In post #10 I wondered if "stationaryism" was an idealized concept at odds with the way the universe actually works (continuous motion). . If we accept this concept then does this continuous motion imply time ? (locally ,globally?) As I said I am excluding purely mathematical representations which do not model anything existing as we observe them externally to our thought processes.(which is how I am seeing this y = A sin(bx) equation) A standing wave is not described by this equation because a standing wave is time limited (the string will eventually dissipate and the "standing" wave will move since ,in the "real" world it is not stationary but moving wrt any observer ) **I hope this is a valid distinction or do we have to say that mathematical models are a subset of the set of natural processes we observe around us?. I'm sorry you don't like my answer to your original question. The whole of quantum mechanics is founded on standing waves (which by definition do not go anywhere). So they are not just a mathematical curiosity they are as real as you or I. As regards your post#10, I did not realise it was a response to my offering. I can only reply to this bit, the rest I see as responding to others or off topic ( but I am willing to be shown otherwise). geordief post#10 was wondering is there any significance to the observation that motion is actually the natural prevailing order of things and that "stationaryism" can be viewed as a limit ? (an idealized state ?) You should look up Earnshaw's theorem in this respect. https://en.wikipedia.org/wiki/Earnshaw%27s_theorem Also note that the 'hot death' can only be momentary, by the kinetic theory.
geordief Posted September 20, 2016 Author Posted September 20, 2016 I'm sorry you don't like my answer to your original question. The whole of quantum mechanics is founded on standing waves (which by definition do not go anywhere). So they are not just a mathematical curiosity they are as real as you or I. i hope you are not getting twitchy I take your point . I could not have been expected to anticipate that fact but I will ,if I am able to try and incorporate it into a new understanding. Was it hard for you to "digest" this information the first time you came upon it? It certainly seems like an aspect of quantum mechanics that bears comparison with other better known features in terms of packing a conceptual punch.(like I say it is completely new to me) Thanks also for the second part of your reply . I will look at that in a while.
geordief Posted September 20, 2016 Author Posted September 20, 2016 (edited) As regards your post#10, I did not realise it was a response to my offering. I can only reply to this bit, the rest I see as responding to others or off topic ( but I am willing to be shown otherwise). Well you were right .It was not in response to your post. It was off topic ,as I said . I could expand but it might clutter up the thread further. I liked Earrnshaw's theorem. Clergymen seem to figure quite a lot amongst mathematicians of the 19th century. There was also Lewis Carroll I think who was something of a reactionary in the discipline (I can't remember the details but I seem to remember reading he fought a rearguard action against the modern mathematical ideas of the time) Edited September 21, 2016 by geordief
studiot Posted September 21, 2016 Posted September 21, 2016 Yes indeed, Victorian vicars have a lot to answer for. The most mathematically famous was probably the reverend Bayes. The standing waves of QM are called De Broglie waves and it is a good job that they do not run down, as suggested by Tim88, as there are De Broglie waves for atoms and sub atomic particles. There is even another current thread ongoing about the lifetime of atoms.
Tim88 Posted September 21, 2016 Posted September 21, 2016 I didn't suggest, I stated an equation which is the equation of a wave which is independent of time. In other words time does not appear in the equation which connects x and y only. Please note I did not state this to be either a travelling wave or a standing wave. We are talking mathematics here [..] In philosophical discussions there is an increased risk of misunderstandings due to a variety of possible meanings of words, but regretfully, what happened here doesn't look like an innocent misunderstanding. The topic here as I interpreted, is not about math but about physics; and my understanding of the topic could not reasonably have been misunderstood, in view of how I defined time in the post to which you responded. Logically I had to assume that you were still talking about a physical wave of the kind that I mentioned and even you also mentioned just before: The wave equation is officially an equation of motion - wave motion. There are two forms of solution to the wave equation, called travelling waves and stationary waves. [..] That is why we say the stationary or standing wave is time independent, (Note this is a less garbled phrase), even though if we look at standing waves on say a stretched string the string is actually in motion. Once more, such standing waves consists, according to standard physics, of propagating waves - as you seem to acknowledge yourself. See also https://en.wikipedia.org/wiki/Wave. Nevertheless, looking back at the discussion I notice a glitch in my answer to the first post, I phrased it the wrong way round (thanks Strange for pointing that out!): In my mind it is not possible to conceive of motion without the concept of time, as time is a measure of the progress of physical processes. Thus motion implies time.
swansont Posted September 21, 2016 Posted September 21, 2016 In my mind it is not possible to conceive of motion without the concept of time, as time is a measure of the progress of physical processes. Thus motion implies time. But that's not the issue. The point of contention was whether time implied motion. Time is a measure of the progress of physical processes, and that implies motion.
geordief Posted September 21, 2016 Author Posted September 21, 2016 (edited) Yes indeed, Victorian vicars have a lot to answer for. The most mathematically famous was probably the reverend Bayes. The standing waves of QM are called De Broglie waves and it is a good job that they do not run down, as suggested by Tim88, as there are De Broglie waves for atoms and sub atomic particles. There is even another current thread ongoing about the lifetime of atoms. If they do not run down why do atoms and subatomic particles have life times at all ?(I am out of my depth but I hope the question is valid) Do these particles simply never decay unless there is a collision with another particle? Are these particles fully described by a standing waves or do they have any attributes that can be desrcibed differently? Edited September 21, 2016 by geordief
swansont Posted September 21, 2016 Posted September 21, 2016 If they do not run down why do atoms and subatomic particles have life times at all ?(I am out of my depth but I hope the question is valid) Do these particles simply never decay unless there is a collision with another particle? Are these particles fully described by a standing waves or do they have any attributes that can be desrcibed differently? Atoms, nuclei and other particles decay if there is a lower energy state is available, and there is a path to get there. Those are the ones with lifetimes. But while they are sitting there, waiting for decay, there need not be any motion; it is not a requirement for the decay.
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