Relativity

Time and Clocks

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  • #374
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    Bruce Nappi
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    This is a discussion about the role of clocks and time as they relate to the Special Theory of Relativity. The topic will be started by entering a long list of posts from an off-site email discussion mostly made up of CNPS members.

    The format of entries will be a comment ID followed by the posted comment. The ID will show the poster’s name followed by the date that the post was made. The comment will only include excerpts that address the scientific focus of this topic. There has been quite a bit of “non-scientific discussion” in the posts that can be considered “lacking in professional respect”. But the appropriate material is presented verbatim so that I don’t inadvertently add my own bias into it.

    This topic is also accompanied by the creation of an experimental tracking MAP. That is, for many of the posts listed here and other posts related generally to the Relativity Group, the scientific discussion was sorted into outline form in a software program supported by MIT that is referred to as the Deliberatorium MAP. Readers can view the outline plus a user guide and a document reference list at the following URLs:
    MAP http://franc2.mit.edu:8000/ci/visit?E-1OPF4AG-603
    MAP user guide http://bit.ly/A3Society-Deliberatorium-User-Guide
    MAP background http://bit.ly/A3Society-The-Internet-Landfill
    Reference list http://A3society.org/Documents/CNPS-Discussion-MAP-References.pdf

    • This topic was modified 7 months, 4 weeks ago by Profile photo of Bruce Nappi Bruce Nappi.
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  • #386
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    # ## Bruce 10/7/16 8:32 AM EDT (clocks)

    From the recent discussions about time, I believe the problem is clear. There is still enough “ambiguity” in many concpets that confusion is certain. So, all those following this subject please help with the following goal:

    Please try to provide a concise definition for the clocks and time that you are using. This is NOT about coming to agreement about an agreed definition yet. It’s about quantifying the number and content ( definition ) of the different beliefs being used in our discussions. I will capture each definition and list it in the Glossary on the MAP. Then we can try to make sense out of all of them.

    Here, again, are the urls for the MAP:

    MAP http://franc2.mit.edu:8000/ci/visit?E-1OPF4AG-603
    MAP user guide http://bit.ly/A3Society-Deliberatorium-User-Guide
    MAP background http://bit.ly/A3Society-The-Internet-Landfill
    Reference list http://A3society.org/Documents/CNPS-Discussion-MAP-References.pdf

    #385
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    # ## Harry 10/7/16 7:42 AM EDT (clocks)

    The claim is that it is possible to create multiple inertial frames of reference in which the velocity of light is the same in all of them. This is where the ambiguity enters, as to how exactly that is to be done. It is preceded by the discussion which says there is no absolute simultaneity. That is needed in order to set up two frames. The main point is there is no justification for the two frames other than to derive the Lorentz transforms.

    Many textbooks skip the part of setting up the frames and simply assume that time is simultaneous in each one of them separately. So you have t time and t’ time. These are related by the LTs. But the equations that are deduced from the LTs produce contradictions. Hence the assumptions that were used to derive the LTs are shown to be false. My conclusion is that the claim that the velocity of light is the same in more than one inertial frame is untenable.

    #384
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    # ## Harry 10/7/16 7:20 AM EDT (clocks)

    I totally agree that the concept of time is ambiguous in SR. This needs to be corrected. I think that there actually is no problem at all once we come to agreement that the so called Einstein synchronization is nothing more than the Newtonian concept of simultaneous universal time applied to the so called stationary frame.

    The way SR buggers up the theory of time is when a second frame of reference is introduced and it is claimed that the same procedure for Einstein synchronization can be applied there. All that does is make this second frame into a copy or more precisely a subframe of the stationary frame. The basic claim of SR is that it is possible to create a second frame that is moving with respect to the stationary frame such that the velocity of light is the same in both frames. This is done in SR but produces contradictions called paradoxes which are said to not be fatal flaws of the process. It should be obvious that the only way that the velocity of light is the same in both the stationary and the moving frame, is when the two frames are not moving with respect to each other. In that case we have no contradictions. But when it is claimed the frames are in relative motion, numerous fatal contradictions arise, which produces numerous disputes which prevents being able to correctly discern that the SR theory is false.

    #381
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    # ## Roger 10/7/16 2:40 AM EDT (clocks)
    “time” is another thing Einstein leaves ambiguous as to how he wants to treat it. He says time is “that which a clock measures”- what is called an operational definition. But he doesn’t really say that the operation should be “Einstein synchronization” ; never addresses issues like – whether there is only one operation or many operations etc. People try to make sense of Einstein by presenting what he should have meant as “Einstein synchronization”…

    #380
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    # ## Harry 10/7/16 2:19 AM EDT (clocks)
    Bruce,

    It appears from the comments so far that you will not be able to get an agreement regarding the basic definition of time that can form the basis of a discussion.

    Here is my proposal for the basis of the discussion. Lets see if we can get agreement on this.

    Einstein’s thesis is that what a clock measures is time. So he attempts to construct a theory regarding the nature of time from a theory regarding the behavior of clocks. That right there is a philosophical issue. But, we can let that pass and following Einstein try to define time in terms of clocks. Noting as we do this that our common notion of time ought to be followed in doing this.

    You say in point one: Clocks are electro-mechanical (as opposed to chemical) instruments that are designed to produce very short periodic indications (ticks). The primary design goal is that the “interval” (“time”) between the indications is uniform.

    This does indeed capture the primary intuition regarding time that it passes uniformly. But clocks are also defined as measuring time according to the scientific standard or international definition of time. That is commonly called UTC and that time includes three concepts. The ticks or beats are uniform in length, the time indications are coordinated to calendar dates through conventions, and lastly that the clocks are all synchronized.

    The definition of synchronized is the problematic part. It basically means simultaneous. To achieve the concept of synchronization or simultaneous universal time, the clocks all measure the same length of the time interval that form their tics or beats, and the dates and times of day are coordinated. It is confusing that in SR the discussion denies that simultaneity exists and then proposes a definition of simultaneity that is called Einstein synchronization. That is a problematic aspect of any discussion of SR. The main point is that Einstein synchronization is just a misnomer, it simply means simultaneous.

    The next issue to be discussed is that clocks don’t record time directly, but do so inversely. That is the time displayed on the dial faces is inversely related to the length of time of the tic or beat. So when the interval of the tic or beat is increased, the dial reading decreases. Now we have to make clear another point which is that frequency is what is really used to define the clock. The frequency is that of the periodic oscillation. It is inversely related to the time interval. So that means that a clock goes fast, when its frequency is higher than the standard clock. which means its dial reading is greater than the standard clock, and inversely for the slow clock. A slow clock reads less time on the dial, has lower frequency and has a longer time interval for its tics.

    All of these points need to be clearly understood before going on.

    Harry

    #379
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    # ## Stephane 10/6/16 11:46 PM EDT (clocks)
    Time in physics has a very specific meaning; it has an operational definition. This is SR’s ‘time’. Its the *value* on a given clock at the location of the event in question.

    When one speaks of ‘time’, one MUST specify the frame and the event and synch procedure. In SR, these are the inertial frames, the event(s) and the e-synch. Not specifying any of these, the word ‘time’ has no operational meaning. So, clocks directly measure time, by definition!

    What you are alluding to as ‘time’ is the common perception thereof, the metaphysical time, Newton’s time. That is a totally different and obsolete meaning, and is NOT what is meant when physicist use the word ‘time’.

    So, if you are discussing physics, ‘time’ is well defined and you should adopt that definition.

    #378
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    # ## Ian 10/6/16 11:15 PM (clocks)

    … regarding clocks measuring time, they actually don’t directly measure time … Clocks are really just a device that repeats itself to a fraction of the orientation of the earth (the second), so it’s not really measuring ‘time’ as such, and as I’ve mentioned before, this slippery concept of time is something emergent and not fundamental at the very least.

    That’s why I asked Matthias, is ‘ct’ REALLY the same sort of animal as ‘x’ that can possess equivalence in the space-time interval equation? Looking forward to an answer to that……

    #377
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    # ## Bruce 10/6/16 2:07 PM EDT (clocks)
    Harry,

    Thanks for taking the time for this in-depth reply. This is what I was hoping for, with the intent of capturing it for the Glossary in the tracking MAP.

    It is a good example of how what seems like a simple concept, can easily go astray simply due to lack of precision in the definitions. Here’s one point you discussed as an example.

    You stated, “This does indeed capture the primary intuition regarding time, that it passes uniformly. But clocks are also defined as measuring time according to the scientific standard or international definition of time. That is commonly called UTC and that time includes three concepts. The ticks or beats are uniform in length, the time indications are coordinated to calendar dates through conventions, and lastly that the clocks are all synchronized.”

    For discussions to be precise, when we use the term “clock”, which of the three elements are included? My “bias” in my discussion comes from electronic circuits. The “clock” in that application is the pulse waveform that drives all the “synchronous” circuits in the computer. That is, it is just the “clicks”. But for someone else who, say, works with stop watches, they view a clock as having both elements 1 and 2 of your example: a “click rate”, and a “counting function”. Synchronizing to other clocks for that example is not important. In your third example, we essentially have a “system clock”.

    I’m sure, we aren’t the first people to have this discussion. Anyone familiar with a “good” and thorough analysis, please reference that. The Wikipedia entry for “clock” just talks about commercial items. The Wiki article on “time” does better in it’s philosophy section. It suggest 2 types of time: 1. Newtonian (realist) time, which is “part of the fundamental structure of the universe”. It never explains, physically, how that works. 2. The other is philosophical, as in Immanuel Kant, being ” an intellectual concept (together with space and numbers) that enable humans to sequence and compare events.” Again, the Greeks already explained this by 500BC.

    #376
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    # ## Harry 10/6/16 1:02 PM EDT (clocks)
    I would like to start a separate discussion thread and focus the discussion on this item as a start. We can call this thread definition of clocks and synchronization. {Expanded to Clocks and Time for this forum}

    Einstein’s thesis is that what a clock measures is time. So he attempts to construct a theory regarding the nature of time from a theory regarding the behavior of clocks. That right there is a philosophical issue. But, we can let that pass and following Einstein try to define time in terms of clocks. Noting as we do this that our notion of time ought to be followed in doing this.

    * * * *
    As a way to start the discussion, Bruce Nappi presented an introduction to a vocabulary about clocks which is included here:

    Let me make some summary statements that I encourage simple comments to, in order to clear up what I sense are some simple ongoing misunderstandings. These will essentially help establish some “working definitions”.

    1. Clocks are electro-mechanical (as opposed to chemical) instruments that are designed to produce very short periodic indications (ticks). The primary design goal is that the “interval” (“time”) between the indications is uniform.
    2. A number of clocks can be brought together in a “non-accelerating” frame and “synchronized”. What determines whether the clocks have met the primary design goal is whether they stay synchronized over long periods.
    3. Various theories are being discussed to try to explain why such a set of clocks, if set in motion relative to each other, have been “observed” to lose synchronization.
    4. It is helpful, due to the complexity of instruments, to try to focus different theories around mutually exclusive principles, so that cause and effect can be isolated and simplified. A common way to study such influences is to run experiments, either empirical or theoretical, that hold all known variables constant while a single variable is changed. We should try to do this first, before searching for second order interferences.
    5. SR is one such theory, where the precise meaning of SR should be considered Einstein’s 1905 paper plus updates. It’s primary variable is relative velocity.
    6. GR is a second theory. While incorporating SR terminology, its primary focus it the variable of gravitation. This variable should be isolated from and discussed separately from relative velocity. Let’s not confuse these.
    7. “Relativity” is a third theory. While originally being based on SR and GR, it has established conditions of its own. Attempts to identify and then study these differences is the key to this effort. But the discussions, relative to SR, should still focus narrowly on relative velocity.
    8. Given that many “critical thinkers” believe that neither SR nor Relativity capture the true causes of relative velocity induced clock variability, similar analyses should be applied to these theories.
    9. As I mentioned in my historical references to Greek studies about LIGHT, theories related to light transmission “controlled” by the source (ballistic), medium (aether), and observer should be addressed and so identified. Note, there is no parenthetical term included for “observer”. I do not know of any modern scientific physical process that has been proposed to explain how an observer can control the speed of light past Pythagoras’ theory in 550BC. Please provide input on this if otherwise.
    * * * *
    You say in point one: Clocks are electro-mechanical (as opposed to chemical) instruments that are designed to produce very short periodic indications (ticks). The primary design goal is that the “interval” (“time”) between the indications is uniform.

    This does indeed capture the primary intuition regarding time that it passes uniformly. But clocks are also defined as measuring time according to the scientific standard or international definition of time. That is commonly called UTC and that time includes three concepts. The ticks or beats are uniform in length, the time indications are coordinated to calendar dates through conventions, and lastly that the clocks are all synchronized.

    The definition of synchronized is the problematic part. It basically means simultaneous. To achieve the concept of synchronization or simultaneous universal time, the clocks all measure the same length of the time interval that form their tics or beats, and the dates and times of day are coordinated. It is confusing that in SR the discussion denies that simultaneity exists and then proposes a definition of simultaneity that is called Einstein synchronization. That is a problematic aspect of any discussion of SR. The main point is that Einstein synchronization is just a misnomer, it simply means simultaneous.

    The next issue to be discussed is that clocks don’t record time directly, but do so inversely. That is the time displayed on the dial faces is inversely related to the length of time of the tic or beat. So when the interval of the tic or beat is increased, the dial reading decreases. Now we have to make clear another point which is that frequency is what is really used to define the clock. The frequency is that of the periodic oscillation. It is inversely related to the time interval. So that means that a clock goes fast, when its frequency is higher than the standard clock. which means its dial reading is greater than the standard clock, and inversely for the slow clock. A slow clock reads less time on the dial, has lower frequency and has a longer time interval for its tics.

    All of these points need to be clearly understood before going on.

    Harry

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