[guest39538]

Time is a measure of the rate of change of a system.

Abstract time is a measure of the rate of change of a system, do not mistake abstract for ''timeless'' time of space.

[timey]

A good article, including

That's because of time-dilation effects. First, time appears to move slower near massive objects because the object's gravitational force bends space-time....

....nothing about the atoms of the clock. Which is why the time dilation effect is exactly the same for all massless photons as it is for electron transitions in an atom, and for all clocks (including rubidium, which preceded cesium). Gravity affects time. And remember that  the frequency of a cesium clock has nothing to do with the mass of, or gravitational pull on, its atoms. It's an entirely quantum-mechanical function of the electron orbitals. If the actual frequency was affected by gravity, the perceived frequency would presumably depend on the chemical makeup of the observer, but it doesn't.

Because space time bends space is the typical layman oriented fob off use of terminology employed by physicists who think the proper explanation is beyond the understanding of their listener.

So you are saying that the mechanism atoms of the clock are not affected by gravity, that the electron clouds are not affected by gravity, and the only thing that is affecting these mechanism of the atomic clock are the factor of what time is doing in the location of the clock?

Yet it is proved that changes in the gravitational field cause the frequency and wavelength of all particles to shift due to a change in their energy.  The fact of all particles having frequency and wavelength is the premiss of the De Broglie hypothesis and forms the basis of quantum mechanics. (quantum mechanics hasn't as yet been linked to gravity).

The gravitational field shift's the 'energy' of the particle with mass, and the frequency of wavelength per standard second, in the same fashion that it shifts the energy of photon's, and their frequency. (albeit photon's are affected in a contrary direction)

Then, according to GR, e=mc2 will cause a change in mass...

 - but you are correct in that the chemical make up of the observer will have no bearing on their perception of a time registered on a clock using the frequency of caesium atoms to measure time, in much the same way that a tall person will not perceive a meter to be any longer or shorter than a smaller person will.  A measure of time is a measurement, and the measure of all time considerations in physics are set by the length of a standard second.  How the atoms of an observer's own physical make up interact with the mechanism atoms of the clock would not be perceivable to the observer in the slightest.  There is a case for the atoms of the observer affecting the mechanism atoms of the clock though, but this effect would not be of the type to initiate the correct shift in their energy transitions from ground state and back cycles.  That would require a 'specific' shift of exactly the correct  and matching frequency, such as a gravitational shift, or a velocity related shift.  And yes, as far as the atom is concerned it will be transiting from its ground state and back again no matter where in a gravitational field you place it, and no matter what speed you subject it to... but relative to the clock registering a standard second at earth's ground level, and at the velocity of earth's transit through space, any change in reference frame is a change in that reference frames clocks ground state energy and frequency - as far as we are concerned on earth and by our earth standard measurements.

[guest39538]

This caesium atomic clock's transitions from ground state and back is the method by which we record time and each change in the rate of time comes complete with a specific frequency in hertz.

There is no change in the rate of time, the change is the measured change of frequency, nothing to do with the ''rate'' of time.






 

If the frequency of those cycles increases, the rate of time is faster, and if the frequency of those cycles decreases, the rate of time is slower. 

No, the rate of cycles is slower that is that, the ''rate'' of time is not slower or faster, the rate of the Caesium atom is nothing to do with time.

[timey]

Quote wiki:
""Caesium clocks are the most accurate commercially produced time and frequency standards, and serve as the primary standard for the definition of the second in SI (the metric system). By definition, radiation produced by the transition between the two hyperfine ground states of caesium (in the absence of external influences such as the Earth's magnetic field) has a frequency of exactly 9,192,631,770 Hz. That value was chosen so that the caesium second equalled, to the limit of human measuring ability in 1960 when it was adopted, the existing standard ephemeris second based on the Earth's orbit around the Sun.[2] ""

And here is a description of the mechanics:

http://www.wired.com/2014/04/nist-atomic-clock/

The caesium atom resonates at the natural frequency of 9,192,631,770 Hz.   Presumably when gravitational time dilation is discussed and the frequency of cycles of the caesium atom increases for a faster rate of time, the natural frequency of the atom being 9,192,631,770 Hz increases?

If this natural frequency of the caesium atom decreases for a faster rate of time in a weaker gravitational field, then I do apologise Alan for completely wasting your time.

If this natural frequency of the caesium atom increases for a faster rate of time in a weaker gravitational field, then again I ask you, why does the caesium atoms frequency and energy increase for a shorter wavelength in a weaker gravitational field, when a photon's frequency and energy decreases for a longer wavelength in a weaker gravitational field?

[alancalverd]

So you are saying that the mechanism atoms of the clock are not affected by gravity, that the electron clouds are not affected by gravity, and the only thing that is affecting these mechanism of the atomic clock are the factor of what time is doing in the location of the clock?

Yes, to the extent that the hyperfine ground state energy difference is not dependent on the local gravitational field.

Good reference! Note that

Cesium atoms in fountain clocks actually experience time differently at the top of the 3-foot chamber than at the bottom.

No suggestion that the atom undergoes any change, but that time is indeed warped by gravity.

If this natural frequency of the caesium atom increases for a faster rate of time in a weaker gravitational field, then again I ask you, why does the caesium atoms frequency and energy increase for a shorter wavelength in a decreasing gravitational field, when a photon's frequency and energy decreases for a longer wavelength in a weaker gravitational field?

Once again, it doesn't. A clock - any clock - in a weaker gravitational field will appear to run faster than one in a stronger field. The red/blue shift is exactly the same for a photon, because they are all subject to the same physics. If you start with an incorrect premise, you can end up in all sorts of trouble. As my old navigation instructor said "always start from where you are, then you won't get lost before you take off."

[timey]

I am starting from the premiss that NIST conducted ground level atomic clock testing of gravitational time dilation.  The clocks didn't just 'appear' be running at different rates of time.  I don't know why you keep referring to the phenomenon as though it were an illusion based on observer dependency.  The experiment stated that an atomic clock at 1 meter elevation registered an increase in frequency of cycles and the clocks rate of time was running faster relative to the identical clock placed 1 meter below it at ground level.  Both clocks could be observed simultaneously by 1 individual.

When they describe an increase in the frequency of cycles for a faster rate of time, are they describing an increase in the frequency that the caesium atom resonates with naturally at ground level or not?

That's a good place to start from...

[timey]

How's about you chiralSPO?  Or evan.au?  Would you be willing to engage in a direct question?

Does the natural resonating frequency of a caesium atom at ground level, this being 9,192,631,770 Hz, increase when the atomic clock is elevated in a weaker gravitational field, or does it decrease?

[jeffreyH (OP)]

How's about you chiralSPO?  Or evan.au?  Would you be willing to engage in a direct question?

Does the natural resonating frequency of a caesium atom at ground level, this being 9,192,631,770 Hz, increase when the atomic clock is elevated in a weaker gravitational field, or does it decrease?

What are you measurements with respect to? The ground level frame or the frame of the caesium atom.

[timey]

The 2010 NIST ground level relativity tests placed 2 identical caesium atomic clocks 1 meter apart in elevation.  The clock at ground level is described as recording the duration of a standard second via the caesium atoms naturally resonating frequency of 9,192,631,770 Hz.
The clock at 1 meter elevation is described as increasing in its frequency of cycles and running at a faster rate of time relative to the clock at ground level.

So in answer to your question Jeff, I'm looking at the different measurement of frequency for both these clocks caesium atoms reference frames.

Due to the doubt Alan has seeded in my mind regarding the question about a particle with mass's frequency increasing or decreasing in a weaker gravitational field, relative to ground level, I am trying to confirm if this description of an increase in the caesium atoms frequency of cycles means that the frequency of the caesium atoms has increased at elevation in the weaker gravitational field.

If the frequency of the caesium atom increases in the weaker gravitational field - and I'm pretty sure if it does then it must be due the addition of  potential energy - then the caesium atomic clock is registering a faster rate of time when in a higher energy state, which does not correspond to current physics, extra energy being equivalent to extra mass and therefore synonymous with a slowing of the rate of time.  And... also casts aspersions on the concept of a clock experiencing velocity, relative to the stationary clock, requiring a further addition of kinetic energy for a slowing of time.  This being because an addition of energy will increase the frequency of the caesium atoms and the clock will register an increase in the rate of time, relative to the stationary clock, which again does not correspond with current physics.

If the naturally resonating frequency of the caesium atom remains unchanged by, or decreases in the weaker gravitational field, and the description given of an increase in the frequency of cycles for the atomic clocks increase in rate of time is not related to the caesium atoms frequency as per the De Broglie hypothesis whereby wavelength is inversely proportional to frequency,  I owe Alan an apology for wasting his time, you too probably, and I shall in future only ever deem to discuss the weather and horses.

[guest39538]

The 2010 NIST ground level relativity tests placed 2 identical caesium atomic clocks 1 meter apart in elevation.  The clock at ground level is described as recording the duration of a standard second via the caesium atoms naturally resonating frequency of 9,192,631,770 Hz.
The clock at 1 meter elevation is described as increasing in its frequency of cycles and running at a faster rate of time relative to the clock at ground level.

Quite hilarious, I am truly beginning to think that the entire world is ''thick''.   For one last time and ''the love of God'', THE CAESIUM ATOM IS NOT IN DIRECT RELATIONSHIP TO TIME AND HAS NOTHING WHAT SO EVER TO DO WITH TIME,

When the frequency rate of the Caesium is slower or faster that is that , you can't say the Caesium runs at a faster rate of time or slower rate of time, you people are all ''mad''.

[alancalverd]

I don't know why you keep referring to the phenomenon as though it were an illusion based on observer dependency.

I don't. It isn't an illusion.

We are talking about relativity here. What you see depends on your speed or gravitational potential relative to what you are looking at. There are no absolutes.

A clock cannot "register" a different time from what it is generating, by definition, but another clock can see the difference between them.

[timey]

Granted Alan... But when NIST place 2 atomic clocks 1 meter apart in elevation - given that the NIST clock operative is likely more than 3 feet tall, both clocks are indeed in the same reference frame as the observer, and are observed by that observer to be running at different rates.

So - I fail to see the relevance of bringing up the relativity aspect when discussing the mechanics of the clock, and questioning if the naturally resonating frequency of the caesium atoms, (being 9,192,631,770 Hz), of the ground level clock, increases or decreases for the clock held at 1 meter elevation relative to the clock on the ground...

[alancalverd]

The observer, in effect, writes down the numbers appearing on the clock faces (it's actually simpler than that - you measure the phase difference accumulated over millions of cycles, between the two signals, and you find it varies in such a way that the higher clock is clearly running faster*).

We define time (and therefore frequency) as what comes out of a standard clock. Relativity says that what comes out of a standard clock will be blueshifted with respect to another if it is at a greater altitude. And it is.

Nothing to do with the mechanics of the clock, which in this case is gravity-invariant. How do we know?  Because (a) if you turn the clock upside down, you get the same answer (b) the calculated relativistic G-blueshift is exactly what is measured and (c) you get the same answer (though with less precision) with rubidium clocks and hydrogen masers, which have very different mechanisms.

both clocks are indeed in the same reference frame as the observer

They are not moving with respect to each other, but the upper clock is at a higher gravitational potential - that's what we mean by "altitude". General relativity is the business of equating a gravitational field to a moving frame of reference.

*It doesn't matter where you measure the phase difference. If you subtract the lower signal from the received upper signal, you can see that the upper clock is running faster. If you do it the other way around, you can see that the lower clock is running slower. 

[timey]

Understood!

But you see how the clock at ground level is calibrated at the frequency of  9,192,631,770 Hz, because that is the natural resonating frequency of the caesium atom, what I am asking is:

Do the caesium atoms of the clock elevated 1 meter in elevation relative to the clock on the ground still resonate at 9,192,631,770 Hz, or does this frequency change?

And if the frequency does change from 9,192,631,770 Hz for the elevated clock, does it increase, or decrease?

[jeffreyH (OP)]

The scale by which a unique frame of reference can be defined has a limit at the Planck scale. So two clocks at a separation of 1 metre elevation must be considered to be in unique and different frames of reference, since the gravitational gradient varies between the two. Simply because two objects are in the same room does not necessarily mean the frames of reference they occupy are identical.

[timey]

Ok, yes the clocks are in different frames of reference, but only 1 meter apart.

My question:

The calibrated frequency of the caesium atoms of the mechanism of the atomic clock on the ground, this being 9,192,631,770 Hz... Do the caesium atoms of the clock elevated at 1 meter operate at a frequency of 9,192,631,770 Hz, or does the elevated position of the clock at 1 meter change this operating frequency?

If the elevated position of the clock does cause this frequency of 9,192,631,770 Hz to change, ie: gravitationally shift, is the frequency an increased frequency, or a decreased frequency in relation to 9,192,631,770 Hz?

[jeffreyH (OP)]

What answer are you expecting?

[timey]

The NIST site states that the frequency of cycles increases for the elevated clock...

Unless there is some other meaning to the phrase of terminology?  Not impossible, hence the question...

[alancalverd]

To be absolutely pedantic, the cesium clock isn't calibrated. It is the universal standard against which all other timepieces are calibrated, so it defines the second, because all cesium clocks operate at the same frequency, everywhere.

Frequency is the number of cycles per unit time. In a lower gravitational field* time speeds up. So if the frequency of the space clock is constant, the number of space clock cycles seen by an observer on the earth in one earth clock second is larger.

Now 3 ft is, in human terms, a significant change in gravitational potential. If you drop a brick on your foot, it really hurts.  But in cosmic terms it's a very small change, so you need two very precise clocks to measure it by time dilation. That said, it's fundamental to the means by which we measure GPS altitude, so if your clock is really good, you can land a plane by it.


*and here's a source of confusion - if the gravitational field is divergent, as with the earth's field, a higher altitude -> lower field strength  = higher gravitational potential. But don't worry about it, it's just a sign convention.

[timey]

When the clock is set up and placed in situ, the microwave beam that the ball of cooled caesium atoms is tossed up through 'must' be calibrated, ie: tweaked.  They know that they have tweaked the microwave beam to the correct frequency that the caesium atom naturally resonates at - this being the frequency of 9,192,631,770 Hz - when the caesium atoms tossed up in the chamber through this microwave beam emit light.

The NIST site states that the clock in the weaker gravity field has an increased frequency of cycles and runs at a faster rate.