Relativity's "time dilation" or clock accuracy alteration

[Crowxe]

i've seen the double slit experiment and the delayed choice . my mind rejected the conclusion, but the experiment setting and configuration of delayed choice is rational and holds water so i accepted the experiment outcome even if it means the world isn't real.

i had to give that intro that sounds irrelevant to the topic just to show that I'm open minded.

Now, for the relativity and time dilation , my argument starts with the light clock, it's designed and calibrated to "count" time in certain conditions same as those large old classic pendulum clocks that are calibrated in certain conditions and they measure time faster in winter as the pendulum rod shrinks or slower during high atmospheric pressure and humidity but we don't age faster in winter nor slower in humid thick air, so why should we say so if a clock that uses different theory gave altered reading??

 

[PeterDonis]

it's designed and calibrated to "count" time in certain conditions

Technically, yes, but they're much more consistent and repeatable conditions than you get with a pendulum clock. Basically you need light bouncing between two mirrors in a vacuum. Under those conditions there is no variability at all in a light clock.

We don't actually use light clocks as our best standard of time, we use atomic clocks, but they are similarly calibrated and controlled to minimize variability.

we don't age faster in winter nor slower in humid thick air, so why should we say so if a clock that uses different theory gave altered reading

I'm not sure I understand the issue. Relativity does not predict that we age faster in winter or slower in humid thick air. It predicts that we age according to the rate of an ideal clock (a light clock or an atomic clock is a close enough approximation to this ideal for all practical purposes) that follows the same path through spacetime.

 

[Crowxe]

Technically, yes, but they're much more consistent and repeatable conditions than you get with a pendulum clock. Basically you need light bouncing between two mirrors in a vacuum. Under those conditions there is no variability at all in a light clock.

We don't actually use light clocks as our best standard of time, we use atomic clocks, but they are similarly calibrated and controlled to minimize variability.
I'm not sure I understand the issue. Relativity does not predict that we age faster in winter or slower in humid thick air. It predicts that we age according to the rate of an ideal clock (a light clock or an atomic clock is a close enough approximation to this ideal for all practical purposes) that follows the same path through spacetime.

i agree, "we age according to the rate of an ideal clock" but when those clocks are moving faster, they are not ideal or accurate thus they give wrong reading , so it's not us that age in different rate

 

[Nugatory]

i agree, "we age according to the rate of an ideal clock" but when those clocks are moving faster, they are not ideal or accurate thus they give wrong reading , so it's not us that age in different rate

It sounds as if you are thinking that relativity says that "a moving clock runs slow". That' not right, and that's not what relativistic time dilation says.

We age at a rate that is in agreement with the rate of an ideal clock that is at rest relative to us, which is another way of saying "following the same path through spacetime as we are". The fact that we and the clock may be moving relative to something or somebody else is irrelevant: right now you are moving at 99.999% of the speed of light relative to someone somewhere in the universe, but that doesn't mean that a clock sitting on the table next to you is any less ideal.

 

[Crowxe]

It sounds as if you are thinking that relativity says that "a moving clock runs slow". That' not right, and that's not what relativistic time dilation says.

We age at a rate that is in agreement with the rate of an ideal clock that is at rest relative to us, which is another way of saying "following the same path through spacetime as we are". The fact that we and the clock may be moving relative to something or somebody else is irrelevant: right now you are moving at 99.999% of the speed of light relative to someone somewhere in the universe, but that doesn't mean that a clock sitting on the table next to you is any less ideal.

what I'm saying is that speed (relative or actual) only affect the clock reading. the clock malfunctions, a clock that depends on the speed of light on its calculation would sure mess up if it travel at speeds close to the speed of light

 

[PeterDonis]

when those clocks are moving faster, they are not ideal or accurate

Look carefully at what I said: we age according to the rate of an ideal clock that follows the same path through spacetime. In other words, we age according to the rate of an ideal clock that is not moving relative to us. (The technical term for this in relativity is "proper time".) The fact that the rate of such a clock looks slower to someone relative to whom it is moving doesn't affect the rate at which we age.

Also, the time dilation of a clock as measured by an observer relative to whom it is moving does not make the clock "inaccurate". As above, it doesn't change the rate at which we age, or at which the clock ticks, at all. It is just a "perspective" effect in spacetime, similar to the way an object's apparent size can change depending on the angle from which you view it.

a clock that depends on the speed of light on its calculation would sure mess up if it travel at speeds close to the speed of light

A light clock doesn't "depend on the speed of light on its calculation". It doesn't "calculate" a rate. It just uses the bouncing of light pulses off a mirror to determine a rate.

i had to give that intro that sounds irrelevant to the topic just to show that I'm open minded.

Are you familiar with the experimental evidence for time dilation? It is at least as strong as the evidence for the quantum phenomena observed in delayed choice and double slit experiments.

 

[Dale]

We can build a variety of clocks using a variety of different frequency standards. If we find that some condition affects one type of clock but not others, then we would say that the clock was inaccurate under those conditions.

However, if all clocks of all mechanisms are affected by exactly the same amount then we may as well say that time itself has changed. There would be no detectable difference between the two, and it is simpler than positing many different effects of the same amount.

The time dilation of relativity corresponds to the second case. We have tested it with clocks based on EM, the strong nuclear force, the weak nuclear force, and gravity. All exhibit time dilation as predicted by relativity.

 

[Crowxe]

Look carefully at what I said: we age according to the rate of an ideal clock that follows the same path through spacetime. In other words, we age according to the rate of an ideal clock that is not moving relative to us. (The technical term for this in relativity is "proper time".) The fact that the rate of such a clock looks slower to someone relative to whom it is moving doesn't affect the rate at which we age.

Also, the time dilation of a clock as measured by an observer relative to whom it is moving does not make the clock "inaccurate". As above, it doesn't change the rate at which we age, or at which the clock ticks, at all. It is just a "perspective" effect in spacetime, similar to the way an object's apparent size can change depending on the angle from which you view it.
A light clock doesn't "depend on the speed of light on its calculation". It doesn't "calculate" a rate. It just uses the bouncing of light pulses off a mirror to determine a rate.
Are you familiar with the experimental evidence for time dilation? It is at least as strong as the evidence for the quantum phenomena observed in delayed choice and double slit experiments.

1. the light clock sounds to depend on the speed of light (the light source, mirror and sensor...etc) if it's 150,000 km between the mirrors then the tick will tick after 1 sec (coz the speed of light is 300,000 km/s) that's my understanding of the light clock

2. I'm familiar with experiment , I've watched different videos much more than i watched the delayed choice, even though the delayed choice more complicated. but maybe there's a catch, the experiment ignore that the light beam should be aimed in angle where the mirror is not there yet, but i assumed the experiment supposes that we aim the light in that certain angle.

3. when i said the clock will not be accurate , that wasnt to an observer or someone beside it , just meant the clock will count the ticks erroneously.

 

[Dale]

light clock sounds to depend on the speed of light

The point of the light clock is that it is easy to analyze. Don't get too hung up on it. The fact is that we have tested clocks of many different operating principles. They all behave as predicted by relativity, regardless of if it is EM, strong, weak, or gravity, or a combination. The evidence really is quite comprehensive and varied.

 

[PeterDonis]

the light clock sounds to depend on the speed of light

The speed of light in vacuum is a physical constant, so saying the clock "depends" on it is saying the clock depends on something that never changes. What's the problem?

the experiment ignore that the light beam should be aimed in angle where the mirror is not there yet

Please give specific references. And not to videos: to textbooks or peer-reviewed papers. (PF has rules on acceptable sources, please review them.) I'm unaware of any such issue with the light clock thought experiment.

just meant the clock will count the ticks erroneously.

And what is your definition of "erroneously"? Remember that, as Dale pointed out, all ideal clocks that follow the same path through spacetime will tick at exactly the same rate. Remember also that according to SR there is no preferred state of motion, so the fact that two clocks in different states of motion tick at different rates does not make one of them "erroneous"; it's just a physical fact that we need to deal with.

 

[Crowxe]

We can build a variety of clocks using a variety of different frequency standards. If we find that some condition affects one type of clock but not others, then we would say that the clock was inaccurate under those conditions.

However, if all clocks of all mechanisms are affected by exactly the same amount then we may as well say that time itself has changed. There would be no detectable difference between the two, and it is simpler than positing many different effects of the same amount.

The time dilation of relativity corresponds to the second case. We have tested it with clocks based on EM, the strong nuclear force, the weak nuclear force, and gravity. All exhibit time dilation as predicted by relativity.

oh... i only know of the one actual experiment done with nuclear watch , no gravity watch if that's the case then i fully accept the theory of dilation . and for now i would just blame the the mirror (light clock) for confusing me

 

[Crowxe]

The speed of light in vacuum is a physical constant, so saying the clock "depends" on it is saying the clock depends on something that never changes. What's the problem?
Please give specific references. And not to videos: to textbooks or peer-reviewed papers. (PF has rules on acceptable sources, please review them.) I'm unaware of any such issue with the light clock thought experiment.
And what is your definition of "erroneously"? Remember that, as Dale pointed out, all ideal clocks that follow the same path through spacetime will tick at exactly the same rate. Remember also that according to SR there is no preferred state of motion, so the fact that two clocks in different states of motion tick at different rates does not make one of them "erroneous"; it's just a physical fact that we need to deal with.

1. the light clock counts time by dividing the distance/speed of light (constant) but if distance changed then it gives different reading
2 erroneously means count wrong to what it should count but dale said all sort of clocks gave the same time variation , so that solves the problem. apparently the hypothetical light clock example is not the best way to introduce someone to relativity and time dialation

 

[PeterDonis]

the light clock counts time by dividing the distance/speed of light

No, it doesn't. It counts time by the number of bounces off the mirrors. We calculate its behavior by dividing the distance between the mirrors by the speed of light, but the clock itself doesn't have to do that; it just works.

erroneously means count wrong to what it should count

And how are you defining what it "should" count? Whether you realize it or not, you are implicitly assuming that there is one preferred state of motion which defines the time a clock "should" count. But relativity says there is no such preferred state of motion. There is no one rate that a clock "should" tick at. There are just ideal clocks moving on their own paths through spacetime, and the time they count depends on the path.

 

[Dale]

oh... i only know of the one actual experiment done with nuclear watch , no gravity watch if that's the case then i fully accept the theory of dilation . and for now i would just blame the the mirror (light clock) for confusing me

Here is one of the best compilations of experimental evidence regarding relativity.

http://www.edu-observatory.org/physics-faq/Relativity/SR/experiments.html

Sections 4 and 5 are particularly relevant, but part of the scientific appeal of relativity is the amazing breadth and depth of data that it explains. A theory that would replace relativity would need to explain all of these results and more.

 

[morrobay]

so the fact that two clocks in different states of motion tick at different rates does not make one of them "erroneous"; it's just a physical fact that we need to deal with.

It was my understanding that stationary clocks and traveling clocks , of any mechanism, all 'tick" at the same rate. Ie. time between ticks. And the traveling clock records less proper time because it traveled a lessor path distance in spacetime.
That Δt' = Δt/γ is referring to total elapsed time.

 

[Mister T]

Now, for the relativity and time dilation , my argument starts with the light clock, it's designed and calibrated to "count" time in certain conditions same as those large old classic pendulum clocks that are calibrated in certain conditions and they measure time faster in winter as the pendulum rod shrinks or slower during high atmospheric pressure and humidity but we don't age faster in winter nor slower in humid thick air, so why should we say so if a clock that uses different theory gave altered reading??

It's not a real clock, it's a thought experiment designed to demonstrate something about the way real clocks behave. It turns out that real clocks actually do behave this way.

It's true that things don't age faster or slower as a result of the precision issues you mention concerning a pendulum clock. It's also true that things do age differently by precisely the amount predicted by the light clock analysis.

 

[Mister T]

apparently the hypothetical light clock example is not the best way to introduce someone to relativity and time dialation

It demonstrates that time dilation is a consequence of the invariance of speed $c$.

 

[stevendaryl]

The significance of light clocks is that it demonstrates that a particularly simple way of measuring time that works correctly according to one frame shows time dilation according to another frame. So comparing with a situation in which physical conditions (cold weather) affect a clock's behavior isn't appropriate. The moving clock versus stationary clock is not about two different physical conditions, it is the SAME clock, looked at from two different reference frames.

 

[Crowxe]

The significance of light clocks is that it demonstrates that a particularly simple way of measuring time that works correctly according to one frame shows time dilation according to another frame. So comparing with a situation in which physical conditions (cold weather) affect a clock's behavior isn't appropriate. The moving clock versus stationary clock is not about two different physical conditions, it is the SAME clock, looked at from two different reference frames.

i know that in any experiment that has more than one variable/input , we have to hold all variables to get the measurement we need. in the hypothetical/theoretical light clock,all components are sped up except for the light , causing the distance traveled to be longer and so it's time measuring device that's kinda designed to give different reading as it speeds up. it doesn't make sense unless it's a clock that doesn't count on light or electricity which i found by accident yesterday , what seems to be the undisputed prroof for time dilation , it's the muon measurement , not actually a clock but particles that should decay before it reach the Earth as it gets born on higher atmosphere (and should live only around 22 microseconds) yet we receive it on earth..the particle lives longer due to its nearly speed of light. i now believe the theory but not its proof

 

[Crowxe]

Here is one of the best compilations of experimental evidence regarding relativity.

http://www.edu-observatory.org/physics-faq/Relativity/SR/experiments.html

Sections 4 and 5 are particularly relevant, but part of the scientific appeal of relativity is the amazing breadth and depth of data that it explains. A theory that would replace relativity would need to explain all of these results and more.

thank you for your patience , i'll look into that link and may return with more questions than i already still have :) . i can't absorb what i doubt and i tend to be skeptic or understand things through fighting it rather than getting along with it

 

[PeroK]

what I'm saying is that speed (relative or actual) only affect the clock reading. the clock malfunctions, a clock that depends on the speed of light on its calculation would sure mess up if it travel at speeds close to the speed of light

There's no such thing as something traveling at close to the speed of light. In the light clock thought experiment both clocks are at rest in their own inertial reference frame and both traveling at the speed of light relative to the other. If one messes up, so would the other.

 

[Mister T]

i know that in any experiment that has more than one variable/input , we have to hold all variables to get the measurement we need. in the hypothetical/theoretical light clock,all components are sped up except for the light , causing the distance traveled to be longer and so it's time measuring device that's kinda designed to give different reading as it speeds up.

It's the same clock viewed by two different observers. One observer is at rest relative to the clock. The other is in motion relative to the clock.

The results of the analysis match what's observed in Nature. That is what it took to convince most physicists that the analysis is correct.

 

[stevendaryl]

i know that in any experiment that has more than one variable/input , we have to hold all variables to get the measurement we need. in the hypothetical/theoretical light clock,all components are sped up except for the light

I don't think you understood my point: It isn't that the clock has been sped up. It's the same clock, looked at from the point of view of another reference frame.

 

[Crowxe]

I don't think you understood my point: It isn't that the clock has been sped up. It's the same clock, looked at from the point of view of another reference frame.

from another frame of reference that sped up ?

 

[jbriggs444]

from another frame of reference that sped up ?

From another reference frame, including one that is inertial and, accordingly, never "sped up".

 

[PeroK]

from another frame of reference that sped up ?

Reference frames are not physical objects. At any time you can look at any physical situation through any reference frame. If you have an aeroplane in flight, you can look at a passenger from the plane's reference frame (passenger sitting still and not moving) or from the ground reference frame (passenger moving at 1000 km/h).

Your contention is that the passenger's wrist watch might stop working because it's traveling at 1000 km/h. But, there is no way to say absolutely that it is the passenger who is moving. In fact, as the Earth is spinning and orbiting the sun, someone on the ground's wristwatch may be traveling much faster - relative to the sun, say.

This illustrates that there is no such thing as absolute velocity. The passenger in the plane is stationary in one frame, moving at 1,000km/h in another, moving at 2,000km/h in another and moving much faster in yet another: 100,000km/h relative to the sun. So, if motion disrupts a wristwatch, none of our watches should work as we orbit the sun at 100,000km/h.

What might disrupt a watch would be acceleration. A watch is more likely to malfunction being rattled on a bicycle at 20km/h than orbiting the sun at 100,000 km/h. Or, there was the long time problem of getting a clock to work at sea. In all cases, it is acceleration and changes in motion that disrupt a mechanism, not pure motion, which cannot in fact be measured.

It is the same with a light clock. One here on Earth would function just the same as one on an aeroplane, just the same as one on a space probe. There is no physical difference in these scenarios that results from a state of absolute motion (or otherwise). That there is no such thing as absolute motion goes back to Galileo, although a lot of people think it came in with Einstein and relativity.

 

[Battlemage!]

i've seen the double slit experiment and the delayed choice . my mind rejected the conclusion, but the experiment setting and configuration of delayed choice is rational and holds water so i accepted the experiment outcome even if it means the world isn't real.

i had to give that intro that sounds irrelevant to the topic just to show that I'm open minded.

Now, for the relativity and time dilation , my argument starts with the light clock, it's designed and calibrated to "count" time in certain conditions same as those large old classic pendulum clocks that are calibrated in certain conditions and they measure time faster in winter as the pendulum rod shrinks or slower during high atmospheric pressure and humidity but we don't age faster in winter nor slower in humid thick air, so why should we say so if a clock that uses different theory gave altered reading??

Special relativity can be seen in Maxwell's equations. That is, it is an electromagnetic theory in a lot of ways. You are made of chemicals. Chemicals are held together by the electromagnetic interaction of protons and electrons. The laws of relativity apply to electromagnetic phenomena. Ergo, they apply to the chemicals that make up your body.

Thus, if relativity affects a clock made of atoms, it affects you too.Edited to add: which brings up an obvious question: if everything we see is held together by electromagnetism, what difference does it make? Every clock of any imaginable type will exhibit behavior in accordance with relativity. It is a small jump to argue that relativity applies to space and time itself, since the results would be identical, and if you make that step you get all the accurate predictions of general relativity too, not to mention the modern formalization of special relativity.

 

[Mister T]

from another frame of reference that sped up ?

If one observer is in motion relative to another, it's possible that neither of them has ever been sped up. They may have been born that way! Moreover, even if they were born not moving relative to each other, there's no way to distinguish between the one who sped up and the one who didn't.

The Principle of Relativity tells us that there is no way to distinguish between a state of rest and a state of steady motion. You seem to believe that the light clock somehow makes this distinction. It doesn't.

 

[Crowxe]

i'm getting more confused than when i first asked my question (although i found the answer in the Muons)

 

[Dale]

I think that your confusion may be coming from the "geometric" view of relativity, which is very intuitive once you get it but it is a new concept for most people.

The basic idea is that time is another dimension in a combined "spacetime". If you think about plotting it on a piece of paper you might put space as the horizontal axis and time as the vertical axis. The big difference with normal Euclidean geometry is that the appropriate measure of "distance" (called the spacetime interval) is $ds^2=-c^2 dt^2 + dx^2 + dy^2 + dz^2$ instead of the usual Pythagorean theorem.

This view is new, but once you start thinking in geometric terms it makes a lot of things come together.

 

[Crowxe]

Mr. Dale , i can't understand exactly, and it's not your fault , it's me with my scientific degree just high school physics education 26 years ago . but since i was 10 years old i heard about time dilation and accepted it for 34 years until i watched the light clock experiment, it made me reject what i believed . if you explain to me in language that i can't understand then i won't argue and just take your word for granted but i can understand the light clock experiment and i can argue with it (not argue with the relativity theory itself) . anyway thanks to the link you gave me, it doesn't only have the Muons measure but the Doppler experiment too along with others but those two were enough . so i believe in the relativity and apologies to Ernestine for thinking he's reckless . my only problems are :
1. the light clock is an experiment that is loosely designed (maybe it was explained wrong, so i hope you can provide me with link that you approve)
2. there's chaos of not only point of views but also understanding relativity, and that's even clear here if you read the comments

Ps: is there any existing/ongoing experiment that ends the argument of our actual speed and direction of movement

 

[Mister T]

i'm getting more confused than when i first asked my question (although i found the answer in the Muons)

I think your misunderstanding is in the way you are thinking about moving clocks. When you move with them they behave the same as they do when you're at rest with them. When they're in motion relative to you they behave differently in your rest frame.

A muon's lifetime, as measured in the muon's rest frame, is not increased simply because it's moving relative to you. But in your rest frame its lifetime is increased.

If you are misled by the light clock analysis you'd do well to understand why. The fault does not lie with the light clock.

 

[PeterDonis]

is there any existing/ongoing experiment that ends the argument of our actual speed and direction of movement

How would you test this experimentally?

 

[Crowxe]

I think your misunderstanding is in the way you are thinking about moving clocks. When you move with them they behave the same as they do when you're at rest with them. When they're in motion relative to you they behave differently in your rest frame.

A muon's lifetime, as measured in the muon's rest frame, is not increased simply because it's moving relative to you. But in your rest frame its lifetime is increased.

If you are misled by the light clock analysis you'd do well to understand why. The fault does not lie with the light clock.

i think I'm getting closer and i understand that my clock will always tick at the same intervals that mind is used to. but still have couple of basic questions to clear misconception in my mind caused by the light clock .

in the light clock, the experiment display a change in the light beam direction leaning towards the direction of movement instead of staying perpendicular to the mirror. There's a difference between the track it should take to meet the mirror and the actual track it should take according to light behavior unless the experiment states that light will behave as ping pong ball bouncing up and down between train's floor and sealing because it gained horizontal speed from the train. to my understanding, the light shouldn't behave like that and it doesn't gain speed from its source's speed

 

[PeroK]

i think I'm getting closer and i understand that my clock will always tick at the same intervals that mind is used to. but still have couple of basic questions to clear misconception in my mind caused by the light clock .

in the light clock, the experiment display a change in the light beam direction leaning towards the direction of movement instead of staying perpendicular to the mirror. There's a difference between the track it should take to meet the mirror and the actual track it should take according to light behavior unless the experiment states that light will behave as ping pong ball bouncing up and down between train's floor and sealing because it gained horizontal speed from the train. to my understanding, the light shouldn't behave like that and it doesn't gain speed from its source's speed

It's interesting that this question seems to come up a lot. The beam of light can only do one thing. If it bounces up and down between the mirrors, it bounces up and down between the mirrors. That is a physical fact. If you are at rest with respect to the mirrors, then you see that as vertical motion. But, if you moving with respect to the mirrors, you see that as a zig-zag motion.

The light beam can't be vertical in your frame and vertical in its rest frame at the same time.