[Stripe]

Originally Posted by CabinetMaker

True by definition.

I am looking for truth without having to define it for myself.

But you could never test it to see if your correction factor was accurate. It would be based on untestable assumptions.

Of course you could! How do you think they keep satellites in synch? And the assumption is testable. The assumption is that gravity affects clocks. When we put synchronised clocks into different gravitational environments we quickly find divergence.

[glassjester]

Originally Posted by Stripe

The assumption is that gravity affects clocks.

If that's the case, what physical processes would gravity not affect?

Let's say, for example, you attached an atomic clock, a radioisotope, and some fruit flies to a satellite and had it orbit close enough to a black hole for the clock to be slowed down. If you retrieved that satellite, wouldn't you find that the clock, the decay of the radioisotope, and the development/aging of the fruit flies had been equally slowed?

[TomO]

Originally Posted by fool

Look at us all getting along.

Yeah....and it's pretty creepy to those of us watching.

Originally Posted by Stripe

I'd prefer to advance the conversation. How does this advance the conversation?

*whew* That's better.

[glassjester]

Originally Posted by CabinetMaker

The mistake you and GJ make is assuming that the frequency of oscillation and the speed of light are somehow the same. This is not true.

I don't think they're the same. I definitely never said that. But one does affect the other.

Originally Posted by CabinetMaker

The frequency is just a count of how many times something happens in a given period of time. That is all. Wave propagation is something else completely and is not effected by frequency. We define one second as roughly 9 billion oscillations of a cesium atom under specific conditions.

All electromagnetic radiation is dependent on the movement of photons. True or false?

[CabinetMaker]

Originally Posted by Stripe

I am looking for truth without having to define it for myself.

In the realm of science, sometimes things are true by definition. That does not make them any less true. In fact, it makes them absolutely true. If something is true by definition then you cannot argue against it. That is why why things are defined only very very carefully.

Originally Posted by Stripe

Of course you could! How do you think they keep satellites in synch? And the assumption is testable. The assumption is that gravity affects clocks. When we put synchronised clocks into different gravitational environments we quickly find divergence.

I think you are struggling with the relative nature of time under certain conditions. Based on the definition of a second, we can always measure one second in any gravitational field by counting the number of oscillations of a cesium atom. The perception of how time flows is different. One second for you on earth and one second for me at the event horizon of a black hole will feel like one second. But my second from your frame of reference will appear different to you than it does to me. Given that time can "flow" differently based on velocity and gravity, it is not possible to have a "universal" second. The definition of a second will always be true at any temperature above absolute zero and it will always give a person an accurate second within their frame of reference.

Just out of curiosity, why do you thing there is or needs to be a "universal" second or a "true" second? It is an arbitrary definition. We define it as 9-billion plus oscillations. What if we meet another race that defines a second as 5-billion oscillations of a cesium atom. Who's second is the real second, theirs or ours?

[dudeman-x]

the amount of time between a woman seeing me, and the woman deciding she just has to have me

[CabinetMaker]

Originally Posted by glassjester

I don't think they're the same. I definitely never said that. But one does affect the other.




All electromagnetic radiation is dependent on the movement of photons. True or false?

True but Immaterial. We are not measuring the speed of the radiation from the cesium atom, we are counting transitions between two energy states of the atom.

the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.[1]

"Periods" is a key word in the definition. A period is one cycle. We are counting the number of cycles. The transitions radiate at a frequency and we count the number of peaks in that radiation, we do not measure how long it takes that radiation to propagate. Because of that, the definition of a second is independent of the velocity of a photon.

[glassjester]

Originally Posted by CabinetMaker

Because of that, the definition of a second is independent of the velocity of a photon.

So if the speed of the photons was .99c instead of c, those 9 billion oscillations would occur in the same amount of time as they do now? What if the speed of the photons (the speed of light) suddenly shifted to 0c? That wouldn't affect the oscillations of caesium?

[Stripe]

Originally Posted by TomO

*whew* That's better.

All that touchy-feely stuff was weirding me out.

Originally Posted by CabinetMaker

In the realm of science, sometimes things are true by definition.

What you say is correct. A second is a second by definition. The problem is that we are required to assume the truth of relativity in order to work this one. Two problems:

1. Relativity is only a mathematical model, useful for correctly calculating gravitational effects. But its descriptions are not to be confused with what is real. When relativity says "Time is relative" or "C is constant", that is for the purpose of the calculation - not for reality. Too many make this error in many fields.
2. There is a much simpler way to conceptualise the issue.

That does not make them any less true. In fact, it makes them absolutely true. If something is true by definition then you cannot argue against it. That is why why things are defined only very very carefully.

It is not true that time can be manipulated.

I think you are struggling with the relative nature of time under certain conditions. Based on the definition of a second, we can always measure one second in any gravitational field by counting the number of oscillations of a cesium atom. The perception of how time flows is different. One second for you on earth and one second for me at the event horizon of a black hole will feel like one second. But my second from your frame of reference will appear different to you than it does to me. Given that time can "flow" differently based on velocity and gravity, it is not possible to have a "universal" second. The definition of a second will always be true at any temperature above absolute zero and it will always give a person an accurate second within their frame of reference.

And this is an issue you will never be able to face while you assume the truth of relativity and adopt the descriptions in the mathematical model as descriptions of reality. The oscillations of a caesium atom counted in one environment are almost certainly more detrimental to the human body than the same number of oscillations in normal gravity. When astronauts travel through weightless environments and at high speeds their bodies are put under great stress. Rather than prolong life, as relativity suggests to those with too much imagination, situations that make clocks run slower are bad for people.

Just out of curiosity, why do you thing there is or needs to be a "universal" second or a "true" second? It is an arbitrary definition. We define it as 9-billion plus oscillations. What if we meet another race that defines a second as 5-billion oscillations of a cesium atom. Who's second is the real second, theirs or ours?

I don't think there "needs to be" anything. There just needs to be a scientific analysis of the facts rather than the science-fiction addled modern cosmology.

[CabinetMaker]

Originally Posted by glassjester

So if the speed of the photons was .99c instead of c, those 9 billion oscillations would occur in the same amount of time as they do now?

Yes. Because we are not measuring the velocity of transitions, we counting the number of transitions that occur and when 9-billion plus have occurred we say that one second has elapsed. Again, that is the definition of a second: 9-billion plus oscillations = 1 second.

Originally Posted by glassjester

What if the speed of the photons (the speed of light) suddenly shifted to 0c? That wouldn't affect the oscillations of caesium?

No. The only way to stop those transitions is to cool the atom to 0°K. At any temperature above that the atom would oscillate. The oscillations are a function of the transition between the two hyperfine levels of the ground state of the caesium 133 atom. When a transition occurs there is microwave radiation associated with that transition that we can use to count the number of transitions that occur.

Now, if the speed of light were 0, no measurement would be possible since there would be no propagation of the radiation or photon if you prefer. (I wonder what would happen to all those photons trying to occupy the same space at the same time would be...)

But, if the speed of light were half of what it was then we would be able to detect the radiation and count the number of periods. Once we have counted our 9-billion plus pulses we would say that 1 second has elapsed. That is true because the rate of transitions is not dependent on the speed at which the radiation caused by those transitions is propagated. Remember, it is the transition between states that cause radiation to be emitted at a particular frequency. We measure that frequency to determine when one second has elapsed.

[glassjester]

Originally Posted by CabinetMaker

That is true because the rate of transitions is not dependent on the speed at which the radiation caused by those transitions is propagated. Remember, it is the transition between states that cause radiation to be emitted at a particular frequency. We measure that frequency to determine when one second has elapsed.

I see the problem (highlighted). You're saying the radiation is a result of the oscillation of the atom. If that were true, you'd be right, the frequency of emission would not be affected by a change in the speed of light.

The only problem is, that's not true. You've got it backwards. The change in state of the caesium atom is caused by its exposure to externally-generated electromagnetic radiation (microwaves).

*Correction, the oscillation is both caused by and the cause of electromagnetic radiation.

[CabinetMaker]

Originally Posted by glassjester

I see the problem (highlighted). You're saying the radiation is a result of the oscillation of the atom. If that were true, you'd be right, the frequency of emission would not be affected by a change in the speed of light.

The only problem is, that's not true. You've got it backwards. The change in state of the caesium atom is caused by its exposure to externally-generated electromagnetic radiation (microwaves).

*Correction, the oscillation is both caused by and the cause of electromagnetic radiation.

Sorry, but no. A photon is emitted (radiated) when there is a change in state from a higher energy to a lower energy. You can think of it as part of the energy in the higher state is converted to a photon so the particle then drops to a lower energy state. This oscillation between higher and lower energy states results in the radiation that allows us to count the frequency of the state changes.

[glassjester]

Originally Posted by CabinetMaker

Sorry, but no. A photon is emitted (radiated) when there is a change in state from a higher energy to a lower energy.

And this process is induced by hitting the caesium with microwave radiation (assumed to be traveling at c, which is why a vacuum chamber is used). The frequency of oscillations is then measured in a way that assumes a constant c as well. Look up how atomic clocks work; if c changed it would definitely affect the clock correspondingly.

[Flipper]

Originally Posted by Stripe

This sort of idea will never be of any practical use.

Yeah, at least they could have used an X-Box 360.

[Flipper]

Originally Posted by Hedshaker

I'm not sure what you mean by "given inertial reference frame"?

Can this "given inertial reference frame" vary? And if so, does a second vary in accordance?

A reference frame is the area local to an observer. Inertial just means "not accelerating" (and not subject to gravity, which is really the same thing as acceleration in general relativity). It doesn't matter if you're at rest or moving at a constant speed.