About time measurement vs measurement of movement

In summary: Your answers help me a lot in understanding the topic. would it be possible (not trying to pose a new theory here, but to rephrase into a viable metaphysical language) to say that: "in a moving system, all internal prosess slows down by the same ratio as a function of the relative speed of the system".? if it is then maybe I'm finally getting it. (my major difficulty is that i am normally studying metaphysics of the natural sciences and the terminology is a bit different concerning the consepts of time and space).It's possible, but it's a bit of a stretch. In general, the slower a system is moving, the more it slows down.
  • #1
rabbetussa
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0
hi.
as a non-physicist reading physicsbokks i have a problem understanding how, in richard feynmans words, "time itself", is measured. feynman seems to move from clock-measurement to "time"-measurement without a justification. as tsr clairly states time-dilation i have a problem of understanding the terminology. do we talk of "time going slower" or of "clocks going slower"? this might seem ridiculous, but it is a point i simply do not understand when reading feynmans "six not so easy pieces" and other semi-introductory descriptions of the theory of special relativity.
 
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  • #2
rabbetussa said:
feynman seems to move from clock-measurement to "time"-measurement without a justification.
Clocks measure time
rabbetussa said:
do we talk of "time going slower" or of "clocks going slower"?.
Slower than what? Time dilation is always relative. It is one clock going slower than another identical clock.
 
  • #3
thanks a.t but i fear that my question is not completely clear. you say "clocks measure time", but it appears to me as if clocks refer to movement in time, not to time itself (as succession). our clocks are based on the regular movement of planets, and regular movement of atoms if you wish, but they are anyway based on regular movement. my problem is that if movement occurs in time and space, there has to be a separation between movement and space and time. but a clock appears to measure only movement. so: is there no separation between clocks and time in tsr? if so; might i just as well say clock-dilation as time-dilation?
 
  • #4
rabbetussa said:
you say "clocks measure time", but it appears to me as if clocks refer to movement in time, not to time itself (as succession).
Not only movement, but all physical processes. You could build a clock based on radioactive decay rate.
rabbetussa said:
so: is there no separation between clocks and time in tsr?
No.
 
  • #5
thank you a.t.. that's all i need to know.
 
  • #6
Hello rabbetussa.

Think of a clock as something periodic (it ticks). the ticks mark the progress of time and counting them gives us the amount of time. Of course we require this ticking rate or period to be constant for an observer at rest with the clock.

Matheinste.
 
  • #7
The idea that clocks slow down (instead of time itself) is essentially Lorentz's aether theory, and it is experimentally indistinguishable from SR. The reason that we typically prefer the idea that time "slows down" is because it is simpler (Occhams razor). The alternative is to explain the several individual mechanisms by which light clocks, mechanical clocks, quartz clocks, atomic clocks, particle half lifes, etc. each coincidentally slow down by the exact same amount.
 
  • #8
thank you dalespam. both for the info and for the will to help. it amazes me how helpful and nice people are in this site.
your answers help me a lot in understanding the topic. would it be possible (not trying to pose a new theory here, but to rephrase into a viable metaphysical language) to say that: "in a moving system, all internal prosess slows down by the same ratio as a function of the relative speed of the system".? if it is then maybe I'm finally getting it. (my major difficulty is that i am normally studying metaphysics of the natural sciences and the terminology is a bit different concerning the consepts of time and space).
 
  • #9
Hello rabbetussa

First of all you cannot just say “in a moving system” as there is no absolute rest system. If you have two frames moving inertially relative to each other, call them A and B, then an observer in A will observe all processes in B to be running slower than his own and vice versa. The amount of slowing is a function of the relative speed. This is of course after allowing for light transmission times. There is no objective truth as to who is keeping correct time. Each sees the others time as running slower than his own.

Matheinste
 
  • #10
This sort of question come around like clockwork. No one seems to care that rulers measure distance. Rulers don't come around like clockwork. There may be something profound here.

Maybe rulers questions are just spaced out at a characteristic distance---say 45000 miles.
 
  • #11
Hello Phrak

I think that people feel more at home with distances. Time seems much more mysterious.
Of course there are fundamental issues with length measurement as well.

Matheinste
 
  • #12
DaleSpam said:
The idea that clocks slow down (instead of time itself) is essentially Lorentz's aether theory...
Maybe, maybe not. I've been in discussions before where people argue that certain types of physical processes might be affected by motion or movement through a gravitational field (ie, a pendulum clock ticks at a different rate on the moon vs on the earth). The person was undeterred by the point that there are different ways to measure time that use different types of physical processes and all show the same time dilation.
 
  • #13
matheinste said:
Hello Phrak

I think that people feel more at home with distances. Time seems much more mysterious.
Of course there are fundamental issues with length measurement as well.

Matheinste
It's just because they hear about time dilation first! We have plenty of people in here who question length contraction, but they have to get past time dilation to get to it!
 
  • #14
matheinste said:
Hello Phrak

I think that people feel more at home with distances. Time seems much more mysterious.
Of course there are fundamental issues with length measurement as well.

Matheinste

I'd like to hear them. But maybe later on, so as not to trounce on the OP's original question.
 
  • #15
russ_watters said:
Maybe, maybe not. I've been in discussions before where people argue that certain types of physical processes might be affected by motion or movement through a gravitational field (ie, a pendulum clock ticks at a different rate on the moon vs on the earth). The person was undeterred by the point that there are different ways to measure time that use different types of physical processes and all show the same time dilation.
I'm sorry, but I don't understand how the concept you describe here differs from Lorentz's aether theory. Can you explain a bit (preferably avoiding gravity if possible so that we can stick to SR)?
 
  • #16
matheinste said:
First of all you cannot just say “in a moving system” as there is no absolute rest system. If you have two frames moving inertially relative to each other, call them A and B, then an observer in A will observe all processes in B to be running slower than his own and vice versa. The amount of slowing is a function of the relative speed. This is of course after allowing for light transmission times. There is no objective truth as to who is keeping correct time. Each sees the others time as running slower than his own.
In Lorentz's theory you could indeed say "moving system" meaning moving wrt the aether which would be the "absolute rest system". Unfortunately, because of the way the aether distorted clocks and rulers there is no way to detect it or determine your velocity wrt it. And, as you mentioned, two observers always see the other clock running slower even if in the aether frame one is "really" running slower. So, although in Lorentz's theory there is an objective truth about what is moving and which clock is keeping correct time, there is no way to experimentally determine it. This is another reason to abandon the aether, it is fundamentally undetectable.
 
  • #17
"in a moving system, all internal prosess slows down by the same ratio as a function of the relative speed of the system".?

Post #9 does answer your question, and a clearer way to rephrase your statement would be:

All internal processes in one inertial frame (one moving system) will appear slower when viewed by an observer in another inertial frame moving relative to the first.
 
  • #18
DaleSpam said:
I'm sorry, but I don't understand how the concept you describe here differs from Lorentz's aether theory. Can you explain a bit (preferably avoiding gravity if possible so that we can stick to SR)?
The gravity example is the easiest because it is true (which helps to confuse crackpots), whereas the argument's I've heard from crackpots about SR are false. I've heard crackpots argue that there is something about motion that makes certain types of clocks tick slower than others. Ie, if you sent a different type of clock up in a GPS satellite, it might act differently. This differs from Lorentz aether theory (or relativity) because in reality all clocks tick at the same rate (in their own frame) regardless of their speed relative to another object.

I say this only because the OP's line of questioning seemed to be going in that direction - implying to me that if speed affects clocks, that it might affect different clocks differently.
 
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  • #19
russ_watters said:
The gravity example is the easiest because it is true (which helps to confuse crackpots), whereas the argument's I've heard from crackpots about SR are false.
A pendulum clock on the Earth does tick at a different rate than a pendulum clock on the moon, but a pendulum clock at rest on the surface of the Earth ticks at the same rate as a pendulum clock moving at a uniform (non-relativistic) velocity wrt the earth.
 
  • #20
DaleSpam said:
A pendulum clock on the Earth does tick at a different rate than a pendulum clock on the moon, but a pendulum clock at rest on the surface of the Earth ticks at the same rate as a pendulum clock moving at a uniform (non-relativistic) velocity wrt the earth.

I think I see a problem with this, Dale. The rate of clock on the Earth would be the same as the rate of a clock at assymtotic infinity. The rate of the clock at assymtotic infinity would be the same as the rate of a clock on the moon...
 
  • #21
Phrak said:
The rate of clock on the Earth would be the same as the rate of a clock at assymtotic infinity. The rate of the clock at assymtotic infinity would be the same as the rate of a clock on the moon...
No, an inertially moving or resting pendulum clock at asymptotic infinity would have a rate of 0:
[tex]\omega =\sqrt{\frac{g}{L}} = \sqrt{\frac{0}{L}} = 0[/tex]
 
  • #22
DaleSpam said:
No, an inertially moving or resting pendulum clock at asymptotic infinity would have a rate of 0:
[tex]\omega =\sqrt{\frac{g}{L}} = \sqrt{\frac{0}{L}} = 0[/tex]

Oh, a pendulum clock! Good grief, how did I miss that. :bugeye:
 

FAQ: About time measurement vs measurement of movement

1. What is the difference between time measurement and measurement of movement?

Time measurement refers to the quantification of the duration of events or the intervals between them. This can be done using units such as seconds, minutes, or hours. On the other hand, measurement of movement involves quantifying the displacement or change in position of an object over a certain period of time. This can be done using units such as meters, kilometers, or miles.

2. How are time and movement related?

Time and movement are closely related as movement cannot occur without the passage of time. In order to measure movement, we often use time as a reference point. For example, we may measure the distance a car travels in one hour (movement) or how long it takes for a pendulum to swing back and forth (time).

3. What tools are used to measure time and movement?

There are various tools used to measure time, such as clocks, watches, and timers. To measure movement, we can use tools such as rulers, measuring tapes, or even specialized equipment like motion sensors or GPS devices.

4. How accurate are time and movement measurements?

The accuracy of time and movement measurements depends on the tools and methods used. In general, modern timekeeping devices can measure time with incredible accuracy, often up to the nanosecond level. Similarly, advanced equipment can measure movement with great precision, but this may also depend on external factors such as environmental conditions or human error.

5. Why is it important to measure time and movement?

Measuring time and movement is crucial in various fields, including science, engineering, and everyday life. It helps us understand and predict the world around us, make accurate calculations and measurements, and improve efficiency in various processes. For example, time and movement measurements are essential in fields such as astronomy, transportation, and sports.

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