What is a Clock? Syncing Technologies Explained

[Umaxo]

I think it's circular. You first need to introduce the concept of time before you can state, address, prove, or otherwise have, that Noether's theorem. The theorem is a statement about time, it is not a definition of time or an operational definition of how to measure it.

The theorem is actually statement about symmetry, not just some predefined time. So doesn't requirement, that definition of time must respect the symmetry of physical world creates some restriction on the possible definition of time?

 

[Ross Arden]

How do we decide what is a clock and how do clocks that rely on different technologies stay synchronized?

a clock is any mechanism that is capable of measuring time ? for instance we could count the number of pulses from a pulsar . If we know the period of the pulsar then we can accurately measure time, without a feed back mechanism.

The period of the pulsar is prolly a function of its mass or some other, non time dependent, parameter that can be accurately measured.

 

[Ross Arden]

a clock is any mechanism that is capable of measuring time ? for instance we could count the number of pulses from a pulsar . If we know the period of the pulsar then we can accurately measure time, without a feed back mechanism.

The period of the pulsar is prolly a function of its mass or some other, non time dependent, parameter that can be accurately measured.

I suppose all clocks only measure a subset of infinite time. What I mean by that is an egg timer only measures three minutes (say). But of course time goes more than three minutes. But unless it is possible to build a clock that goes for all time, all clocks only measure a subset of the entire time of the universe. In other words all clocks are egg timers, that just run longer than three minutes. I suppose going in the other direction you could have a clock that consisted of a single tick? which would be just a very short egg timer

the big bang is a clock that ticks every 15 billion yrs ?

 

[Paul Colby]

A clock, much like a meter stick for distance, measures time intervals, the time passed between events.

 

[PeterDonis]

the big bang is a clock that ticks every 15 billion yrs ?

No; the Big Bang is not a periodic phenomenon. Unless you are expecting to see another one real soon now...

 

[Ross Arden]

No; the Big Bang is not a periodic phenomenon. Unless you are expecting to see another one real soon now...

assuming there was a big bang. That means there was enough mass in the universe , or some unknown phenomena, to cause the universe to collapse in on itself, to a singularity, and then expand again from that point. Unless there has been significant mass loss, or the phenomena no longer exists, then it is reasonable to assume at some time in the future there will be a second big bang ?

It may be a repeating phenomena with a say 200 billion year period

Another possibility is there are several universes and the material from one big bang is ejected towards another universe causing it to collapse so you have several neighboring universes in varying degrees of expansion and collapse.

 

[weirdoguy]

That means there was enough mass in the universe , or some unknown phenomena, to cause the universe to collapse in on itself, to a singularity, and then expand again from that point.

No, Big Bang definitely does not mean that... Big Bang theory states that universe was in a hot dense state a long long time ago, was expanding, etc.. No collapsing on itself, no singularity treated as a physical thing, no expanding from a point. Use "search" option, there has been many threads about BB clearing that kind of misconceptions.

 

[Mister T]

assuming there was a big bang. That means there was enough mass in the universe , or some unknown phenomena, to cause the universe to collapse in on itself, to a singularity, and then expand again from that point.

I think you have somehow misunderstood that line of reasoning. The latter is not a consequence of the former. That is, having a big bang does not imply that it was preceded by a big crunch. Cosmologists used to speculate that such a thing was possible and that a big crunch might be in our future; but ever since it was discovered, about 20 years ago, that the expansion is accelerating, they stopped. AFAIK.

 

[russ_watters]

the big bang is a clock that ticks every 15 billion yrs ?

Clocks do not require periodic phenomena, just a measurable physical process with a predictable time rate. See: hourglass, radioactive decay...

...and in Jurassic Park, cases of beer.

 

[Ross Arden]

we seem to have drifted off the point ...can someone tell me where I went wrong with my analysis

 

[jbriggs444]

we seem to have drifted off the point ...can someone tell me where I went wrong with my analysis

What analysis and what point?

 

[Torog]

It's not an inertial factor. The nucleus doesn't rotate in the way that a bar magnet rotates.

OK as I said I’m not the expert.
But then you say:

But if you try to account for these behaviors by modeling the nucleus as a sphere, or really an object of any shape, given its known mass and charge distribution, you just can't get it to work out. In other words, the nucleus cannot be modeled as a rotating object. It just doesn't work.

Here it sounds as if you are not sure how it works and I never suggested it might be a sphere.
You say:

Inertia is not the well-formed concept in relativistic physics that it is in the Newtonian approximation.

Well it should be or if it is not then something is wrong – IMHO- tell somebody who has just had his car smashed by inertial forces “well sorry your car is all bent up but we have no way to understand the forces that caused all that destruction” Blame Newton not Einstien.

To get back to “it is not an inertial factor”
Lets see what I understand about Cs133. It has mass so the bits that make up the nucleus, the protons and neutrons have mass and even the electrons have a small amount of mass. The nucleus is emitting a radio wave at a frequency of 9,192,631,770 Hz.
( Getting my information in a cursory manner from : http://hyperphysics.phy-astr.gsu.edu/hbase/acloc.html)
According to the information source above the hyperfine emission comes from an interaction between a lone distant electron and the nucleus (& the dimensions are given for the nucleus and it doesn’t matter if it's round or shaped like a unicorn). It is a dynamic system. It moves – it’s some sort of an engine that produces these electromagnetic waves. You say the mass of the parts have no effect on the emission? It seems to me that if there is any movement involved in the hyperfine emission then the mass/weight of the parts must come into the equation.

Look at it from a GR (or SR?) perspective and with the principle of equivalence gravity and inertia can be interchanged so if the intensity gravitational field effects the clock - proven,of course – then why can’t we postulate that if the inertial mass of the clock changes then its rate will change?

 

[jbriggs444]

Lets see what I understand about Cs133. It has mass so the bits that make up the nucleus, the protons and neutrons have mass and even the electrons have a small amount of mass. The nucleus is emitting a radio wave at a frequency of 9,192,631,770 Hz.
( Getting my information in a cursory manner from : http://hyperphysics.phy-astr.gsu.edu/hbase/acloc.html)
According to the information source above the hyperfine emission comes from an interaction between a lone distant electron and the nucleus (& the dimensions are given for the nucleus and it doesn’t matter if it's round or shaped like a unicorn). It is a dynamic system. It moves – it’s some sort of an engine that produces these electromagnetic waves.

None of this is accurate. A nucleus is not an engine - it does not produce energy. In addition, "dynamic" and "it moves" are not synonyms.

A "state space" within which a dynamic system evolves need not involve three dimensional locations.

 

[Paul Colby]

The hyperfine interaction is between the magnetic moment of the nucleus, which is a constant, and the electrons in the atom. The transition frequency should be a know function of electron mass.

 

[Torog]

None of this is accurate. A nucleus is not an engine - it does not produce energy. In addition, "dynamic" and "it moves" are not synonyms.

A "state space" within which a dynamic system evolves need not involve three dimensional locations.

I realize there it isn't possible to pin down shape of the nucleus or where any bits are at anyone time but is there movement or rotation in the nucleus?

I have heard that "spin" is actually spin with angular momentum and other that say it is "intrinsic" (whatever that means) and doesn't connote any movement.

 

[Nugatory]

I have heard that "spin" is actually spin with angular momentum and other that say it is "intrinsic" (whatever that means) and doesn't connote any movement.

They're both right. The spin of a subatomic particle is indeed angular momentum, and it doesn't connote any movement or physical rotation. "Intrinsic" just means that nothing you do the particle will change its spin.

 

[jbriggs444]

The hyperfine interaction is between the magnetic moment of the nucleus, which is a constant, and the electrons in the atom. The transition frequency should be a know function of electron mass.

Since the frequency of the radiation associated with that transition (as opposed to the "transition frequency") is a defined constant, whatever it is a function of, it is a constant function.

 

[Mister T]

But if you try to account for these behaviors by modeling the nucleus as a sphere, or really an object of any shape, given its known mass and charge distribution, you just can't get it to work out. In other words, the nucleus cannot be modeled as a rotating object. It just doesn't work.

Here it sounds as if you are not sure how it works and I never suggested it might be a sphere.

Not sure how what "works"? Do you mean that the nucleus has a magnetic moment and an angular momentum? You measure those two quantities and don't get values of zero for either one. Is that what you mean by "how it works"?

And I agree that you never suggested it was a sphere.

Well it should be or if it is not then something is wrong – IMHO- tell somebody who has just had his car smashed by inertial forces “well sorry your car is all bent up but we have no way to understand the forces that caused all that destruction” Blame Newton not Einstien.

As I told you, it's not about the physics, it's about the meaning of a word. Inertia. Inertial forces are not the same thing as inertia, their values don't even have the same units.

When cars collide, by the way, they get smashed by electromagnetic forces.

 

[Dale]

tell somebody who has just had his car smashed by inertial forces

Inertial forces never ever smash a car. They are strain free. They occur in non inertial frames, and can be made arbitrarily large by choosing appropriate coordinates. Cars don’t get smashed or not if you choose a different coordinate system.

It has mass so the bits that make up the nucleus, the protons and neutrons have mass and even the electrons have a small amount of mass.

All clocks have mass, so they all have inertia. So what do you mean by “inertial factor”? Do you merely mean that it has inertia? If so then it is a fairly trivial statement that doesn’t describe much about clocks. Do you mean something more?

Clocks have inertia. Cars have color. Color is not the operating principle of a car. Are you simply stating that clocks have inertia or are you trying to say that inertia is the operating principle for all clocks? Are you merely saying the equivalent of “all cars have a color factor”.

 

[Paul Colby]

Since the frequency of the radiation associated with that transition (as opposed to the "transition frequency") is a defined constant, whatever it is a function of, it is a constant function.

Google yields...

"Transition frequency may refer to: A measure of the high-frequency operating characteristics of a transistor, usually symbolized as f. A characteristic of spectral lines. The frequency at which changes in the hyperfine structure of atoms occur. Turnover frequency in enzymology."

Seems to match my usage? Did I miss a memo?

 

[jbriggs444]

Google yields...

"Transition frequency may refer to: A measure of the high-frequency operating characteristics of a transistor, usually symbolized as f. A characteristic of spectral lines. The frequency at which changes in the hyperfine structure of atoms occur. Turnover frequency in enzymology."

Seems to match my usage? Did I miss a memo?

The frequency of the radiation corresponding to the hyperfine transition in the ground state of the cesium atom is not the rate at which changes in the hyperfine structure of atoms occur.

 

[Paul Colby]

The frequency of the radiation corresponding to the hyperfine transition in the ground state of the cesium atom is not the rate at which changes in the hyperfine structure of atoms occur.

Hyper fine structure is a property observed in spectral lines of an atom. This has zip to do with the rate of transition. Not all transitions need be to the ground state. It's an RF spectral line.

 

[jbriggs444]

Hyper fine structure is a property observed in spectral lines of an atom. This has zip to do with the rate of transition. Not all transitions need be to the ground state.

Fair enough. I mis-read your reference to "frequency at which" as "frequency with which".

 

[Torog]

The hyperfine interaction is between the magnetic moment of the nucleus, which is a constant, and the electrons in the atom. The transition frequency should be a know function of electron mass.

So if the mass of the electron changes (in my imaginary world) does the transition frequency change?

 

[Dale]

So if the mass of the electron changes (in my imaginary world) does the transition frequency change?

That depends on how* the mass changes. Specifically, does the mass change in a way that also changes the fine structure constant (or other dimensionless constants) or does it change in a way that they do not change? The measurable transition frequency depends on the dimensionless constants like the fine structure constant.

*how meaning the details about the other changes that might be associated, not the mechanism of change

 

[Paul Colby]

So if the mass of the electron changes (in my imaginary world) does the transition frequency change?

The interaction Hamiltonian which determines the frequencies of transition depends on the magnetic moments which depend on particle mass. Everything changes if $\hbar$ changes as well. These are all observed to be constant as far as I've heard.

 

[russ_watters]

So if the mass of the electron changes (in my imaginary world) does the transition frequency change?

Why does this even matter? The mass of an electron is fixed.

 

[Wes Tausend]

Torog, I appreciate your thinking, and then questions following on how we might define a clock. This is a good thread to help at least some of us attempt to properly anchor the roots of time itself.

First, I should correct my previous assertion (below) that all clocks rely on angular momentum... not certifiably true. It arose from a different, also unmentionable personal idea.

All our clocks have this common denominator. They all rely on angular momentum, or a portion thereof , one way or another, to stay synchronized and count off rotations or portions thereof (pendulum).

DrGreg properly rejected my reasoning on a surviving earlier post and I hereby acknowledge he is correct; strictly angular momentum cannot be the charred key we seek here. My bad.

I find of particular interest what Sorcerer and Dale have discussed above in posts #68 & #69. While I struggle to understand the abstract math symbols of Noether's Theorem, I think I do recognized the conceptual value of, "the principle of least action", as partially worded in this first paragraph. This paragraph seems very much along the lines of Occam's Razor, or as Maupertuis supposedly felt, that "Nature is thrifty in all its actions".

It seems that the ultimate object of science is to simplify whatever processes and observances of Nature that we can. For instance, we might strongly suspect Mother Nature is lazy, that she accomplishes her vocation in the simplest manner possible... and when sufficiently 'cooked', these actions should boil down to fundamental principles... in other words the very charred essence of what we seek. I really like the simplicity of conservation of energy idea for this and other reasons.

Prior to the conservation of energy posts, I was tempted to come back and suggest that, since all classical clocks seem to at least rely on non-erratic motion events, that perhaps conserved general momentums (not just angular) were still the key. Even a candle flame, water or sand must move non-erratically to usefully differentiate the increments as a clock. But 'conservation of energy' seems a much better key now that it has emerged from the soot... because 'conservation of energy' allows not just conserving momentum, but storing that momentum for reuse as counter-momentum if we wish. Clocks commonly work by stored energy and each burst is measurably the same as last. As food for thought, it seems perhaps an escapement loop principle somehow regulates them all.

In a non-classical view, regarding quantum behavior of atoms when remarks on motion were given by Mister T, I am still not so sure I can draw an obvious conclusion that there is an obvious discernible atomic counterpart to classic laws of motion, but that is just me. In my quantum fog, it seems we should only know either the position of the 'tiny' hands or the rate, but not both at the same time. Yet atoms furnish us a great timepiece, apparently by rate alone. It is like a blind man that can hear, and use, the precise tick-tock but need not see the position of the hands to tell time.

But then conservation of energy was brought up. Ok, I know energy transcends both mechanical and quantum. This is better. Just "hearing" the tick-tock of an atom is the process of periodic electromagnetic energy escaping, enough as to form a useful timepiece, particle position notwithstanding. The electromagnetic energy will escape and tell us time until it runs out, or ceases to be applied, like any other clock. Perhaps someone could explain if both atomic and mechanical share a comparable hidden escapement mechanism to not release their energy nearly all at once. Seems maybe worth a Nobel Prize... unless it's been done.

You qualify the above with (pendulum). Isn't it possible that if you drill down into the mechanism of all clocks you will find Inertial mass somewhere in the regulating mechanism.

Thanks, this is what interests me, the how or physics of the regulating mechanisms of clocks.

It is still not so clear to me why 'drilling down' would not succeed, why Nature would suddenly abandon her simplicity right at the bottom of the hole. It's difficult to leave Einstein's side and not share his desperate want to discover why random motion seemingly rules so non-erratically at the core. How can something so random as the ghostly gears of an atom be our best clock? Perhaps we will only really know the atomic mechanism in a heuristic mechanical sense, if or when Einstein's dice ever reveal their secret. Quantum gravity heck; what is quantum time? Non sequor...

---------------------------------------------------------------------------------
It seems a thread like this, where there is not a specific single answer to cite, elicits more opinions that border on speculation. The safer route seems to be saying not much, which I've tried to avoid. I hope I am ok today.

To be upfront, I was the (or a) guilty party in earlier setting foot outside the rules box and got a time-out. I apologize, my zeal to somehow add insight occasionally precedes my head. My uncited previous post, especially about cosmology, was removed and I deserved it. I do very much continue to appreciate the tedious behind-the-scenes work done here by Mentors even when it turns out I'm the rascal gone Beagle Boy. So thanks, Mentors.

And thankfully Torog's worthy clock thread was not locked on my account.

Wes

 

[Torog]

Why does this even matter? The mass of an electron is fixed.

This is just what I was trying to understand. The stability of the electronic clock is at least partially based on the fact that the mass is fixed.
I would like to say more but it is not a subject for this forum.

 

[Dale]

@Torog you didn’t answer any of my requests for clarification on this topic.

 

[Torog]

All clocks have mass, so they all have inertia. So what do you mean by “inertial factor”? Do you merely mean that it has inertia? If so then it is a fairly trivial statement that doesn’t describe much about clocks. Do you mean something more?

Clocks have inertia. Cars have color. Color is not the operating principle of a car. Are you simply stating that clocks have inertia or are you trying to say that inertia is the operating principle for all clocks? Are you merely saying the equivalent of “all cars have a color factor”.

Is this the question you want me to answer? Rather offensive actually. You imply that aside from being ignorant (which I admit) I am also stupid.

What I have been trying to ask is inertia a factor in the stability of clocks? It is in my pendulum clock, my balance wheel watch and in the stability of the orbital period of the Earth. Does it apply to Atomic clocks? Or other clocks?

I also asked this about the speed of clocks. Never got an answer.

Look at it from a GR (or SR?) perspective and with the principle of equivalence gravity and inertia can be interchanged so if the intensity gravitational field effects the clock - proven,of course – then why can’t we postulate that if the inertial mass of the clock changes then its rate will change?

 

[jbriggs444]

Inertial mass is not a factor in the tick rate of a light clock.

Or, to put it differently, inertial mass is as much a factor in the tick rate of a light clock as it is in the length of a ruler.

 

[Dale]

Is this the question you want me to answer? Rather offensive actually. You imply that aside from being ignorant (which I admit) I am also stupid.

This is not acceptable. I never said nor implied any such thing, nor did I even think it.

You are asking a question about a broad topic using non standard terminology and it appears that the responses have been unsatisfactory to you. There are two possibilities, one is that your question was correctly understood and you just don’t like the answer, and the other is that your question has not even been understood so the responses have been responding to misinterpretations of your question. I believe that second possibility is the case here.

The proper thing to do in that second case is to ask for clarification. To challenge the questioner to address their unspoken assumptions and express the meaning behind their terminology. That is a correct intellectual approach, to which you have twice responded exceptionally emotionally.

You have not been bullied, nor cut off, not called ignorant, nor stupid. You have been asked for clarification and asked to examine and express the meaning of your question. Instead of responding substantively and helping to clarify your question, you have inaccurately assigned very negative motives to me and avoided the question.

 

[Dale]

What I have been trying to ask is inertia a factor in the stability of clocks? It is in my pendulum clock,

In what way is inertia a factor in a pendulum clock? A pendulum clock has mass, but its frequency does not depend on its mass. So are you asking about the color of the car or the engine of the car?

A light clock also would have mass, but its frequency would be independent of the mass. So is that all you mean by “inertial factor”, does merely having mass qualify or is there a further qualification implied by your terminology. If so, what is that qualification?

Look at it from a GR (or SR?) perspective and with the principle of equivalence gravity and inertia can be interchanged so if the intensity gravitational field effects the clock - proven,of course – then why can’t we postulate that if the inertial mass of the clock changes then its rate will change?

I don’t think that is a correct statement of the equivalence principle. Roughly the equivalence principle says (with some qualifiers) that gravity is equivalent to acceleration. But acceleration is not the same as inertia, so I wouldn’t say that gravity is equivalent to inertia.

 

[PeterDonis]

Rather offensive actually. You imply that aside from being ignorant (which I admit) I am also stupid.

@Torog, please moderate your language. You are very close to a warning. @Dale is trying to help you.

What I have been trying to ask is inertia a factor in the stability of clocks?

As both @Dale and @jbriggs444 have responded, the answer is no.