OK Relavists
- Thread starter MacM
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Let's incorporate quantum mechanics into this discussion. It is idealised but it will serve its purpose.
Let's say we have a specific element with a sample placed at the front of the rocket and a sample placed at the rear(you could simply put this arrangement in a gravitational field, with one sample placed above the other).
Now the sample at the rear of the rocket is in excited state, which has a specific half life. Now when the rocket is at rest the atom undergoes a transition to a lower state, it will emit a photon with a characteristic frequency of the atom, namely as a function of the difference in energy of the excited state and the ground state.
By the process of stimulated absorbtion, the photon emitted from the rear of the rocket will have a resonant frequency such as to excite an atom in the sample in the front of the rocket, i.e. promote one of its electrons to an excited state.
The probability of absorption is maximum when the frequencies exactly coincide, but the Heisenberg Uncertainty priciple tells us that the frequency has a finite variance about the mean frequency, i.e. the energy difference between the 2 states. Now an observer at the front of the rocket uses the rate at which the sample in front of him becomes excited as a time measurement as, if a constant flux of photons is incident on his sample, the level of excitation of his sample (thee number of excited atoms) will increase linearly w.r.t. to his stop watch.
Now the rocket undergoes an acceleration of say 5g.
The photons at the rear of the rocket emit photons which now, w.r.t. the sample at the front of the rocket, are redshifted. Thus now the photons incident on on the sample no longer satisfy the resonance condition, and the number of atoms excited per unit time decreases.
Question. Does the observer at the front of the rocket observe that the sample in front of him takes longer to become excited?
Have a go at that Mac.
Let's say we have a specific element with a sample placed at the front of the rocket and a sample placed at the rear(you could simply put this arrangement in a gravitational field, with one sample placed above the other).
Now the sample at the rear of the rocket is in excited state, which has a specific half life. Now when the rocket is at rest the atom undergoes a transition to a lower state, it will emit a photon with a characteristic frequency of the atom, namely as a function of the difference in energy of the excited state and the ground state.
By the process of stimulated absorbtion, the photon emitted from the rear of the rocket will have a resonant frequency such as to excite an atom in the sample in the front of the rocket, i.e. promote one of its electrons to an excited state.
The probability of absorption is maximum when the frequencies exactly coincide, but the Heisenberg Uncertainty priciple tells us that the frequency has a finite variance about the mean frequency, i.e. the energy difference between the 2 states. Now an observer at the front of the rocket uses the rate at which the sample in front of him becomes excited as a time measurement as, if a constant flux of photons is incident on his sample, the level of excitation of his sample (thee number of excited atoms) will increase linearly w.r.t. to his stop watch.
Now the rocket undergoes an acceleration of say 5g.
The photons at the rear of the rocket emit photons which now, w.r.t. the sample at the front of the rocket, are redshifted. Thus now the photons incident on on the sample no longer satisfy the resonance condition, and the number of atoms excited per unit time decreases.
Question. Does the observer at the front of the rocket observe that the sample in front of him takes longer to become excited?
Have a go at that Mac.
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Correct
Zanket,
ANS: This is a correct posting of Einsteins statement. Note that it refers to measurement not limit. I also say you will never measure or see v=>c. Lorentz Contraction reduces its dimension to zero. It ceases to exist in the observers physical universe but it doesn't go out of existance nor suffer any affects of its velocity from its frame of reference. It must continue to exist on a higher energy plane.
Zanket,
ANS: This is a correct posting of Einsteins statement. Note that it refers to measurement not limit. I also say you will never measure or see v=>c. Lorentz Contraction reduces its dimension to zero. It ceases to exist in the observers physical universe but it doesn't go out of existance nor suffer any affects of its velocity from its frame of reference. It must continue to exist on a higher energy plane.
Points
There is no velocity induced red-shift.
The situation is the same as if the sample was placed in a gravitational field which was locally flat, i.e. space-time curvature is zero. This is the same as assuming that when you draw a triangle on a piece a paper, we can assume locally that the world is flat, when in actual fact it is not, it is round.
This problem has no errors, but is based on 2 axioms.
1.The equivalence of gravity and acceleration.
2.The invariance of the speed of light.
This experiment has been performed.
The sample activity will increase linearly initially, which is the situation we are investigating. After a certain amount of time an equilibrium will be reached where the number of absorbing atoms equals the number of emitting atoms in the sample of the front of the rocket. If the half life of the sample is long enough, then the situation is exact.
The cross-section of the atom remains unchanged i.e. its absorption spectrum remains unchanged, but remember it is a function of frequency. The results lies in the fact that the majority of atoms emitted by the sample at the rear of the rocket are red-shifted.
I would like to point out that this effect has been experimentally observed in a locally flat gravitational field, by some big Uni in the U.S. (Stanford or Princeton I think, I'll get back to you on that)
So by axiom 1, this result is applicable to the experiment above.
So answer the Question. Does the observer at the front of the rocket observe that the sample in front of him takes longer to become excited? Further for the case of equilibrium as stated above, are the number of excited atoms at equilibrium the same for when the rocket is at rest and when it is accelerating.
There is no velocity induced red-shift.
The situation is the same as if the sample was placed in a gravitational field which was locally flat, i.e. space-time curvature is zero. This is the same as assuming that when you draw a triangle on a piece a paper, we can assume locally that the world is flat, when in actual fact it is not, it is round.
This problem has no errors, but is based on 2 axioms.
1.The equivalence of gravity and acceleration.
2.The invariance of the speed of light.
This experiment has been performed.
The sample activity will increase linearly initially, which is the situation we are investigating. After a certain amount of time an equilibrium will be reached where the number of absorbing atoms equals the number of emitting atoms in the sample of the front of the rocket. If the half life of the sample is long enough, then the situation is exact.
The cross-section of the atom remains unchanged i.e. its absorption spectrum remains unchanged, but remember it is a function of frequency. The results lies in the fact that the majority of atoms emitted by the sample at the rear of the rocket are red-shifted.
I would like to point out that this effect has been experimentally observed in a locally flat gravitational field, by some big Uni in the U.S. (Stanford or Princeton I think, I'll get back to you on that)
So by axiom 1, this result is applicable to the experiment above.
So answer the Question. Does the observer at the front of the rocket observe that the sample in front of him takes longer to become excited? Further for the case of equilibrium as stated above, are the number of excited atoms at equilibrium the same for when the rocket is at rest and when it is accelerating.
Thanks
ryans,
Thanks for the clarifications. Based on your statements there should be a decrease in the number of absorbtions and activations of the front sample.
But I am left with the same problem in that your statement was that the front sample was his clock. Even if there were a decrease in the activation rate he would not know it unless he had an alternate clock to check it by or the rate became obvious to him biologically due to radical or noticable change.
I am not accusing you of a trick question here, I just think I am missing something. I believe there is a change in the sample but you have given me no means of measuring it.
ryans,
Thanks for the clarifications. Based on your statements there should be a decrease in the number of absorbtions and activations of the front sample.
But I am left with the same problem in that your statement was that the front sample was his clock. Even if there were a decrease in the activation rate he would not know it unless he had an alternate clock to check it by or the rate became obvious to him biologically due to radical or noticable change.
I am not accusing you of a trick question here, I just think I am missing something. I believe there is a change in the sample but you have given me no means of measuring it.
OK
ryans,
OK. I see the stop watch now.
As I have said I know of quantum mechanics and some general things about it but nothing actually technical but since you seem to want to get me to give you an answer, just so you can say "See I told lyou he doesn't know QM", I don't mind. Because there is plenty you don't know.
My intuition says he will see a change.
PS you haven't commented on my post:
ryans,
OK. I see the stop watch now.
As I have said I know of quantum mechanics and some general things about it but nothing actually technical but since you seem to want to get me to give you an answer, just so you can say "See I told lyou he doesn't know QM", I don't mind. Because there is plenty you don't know.
My intuition says he will see a change.
PS you haven't commented on my post:
I Understand
Janus,
I understand you guys like to rub each others back but your position has been made clear. Objects in a gravity field respond to the depth of the field they are positioned in and a rocket standing vertical in a gravity field has a gradient or depth quality.
He then states that it is in a flat field. How you get a flat field is questionable to me (my take on his claim is that the field gradient is insignifigant and is to be disregarded, not that none is there) unless you lay the rocket down but in any case he qualified it as flat and I have proceeded.
Are you saying now that depth of field has no affect or that gravity around earth has no radial depth content?
Waiting your clarification for this ever moving target.
Janus,
I understand you guys like to rub each others back but your position has been made clear. Objects in a gravity field respond to the depth of the field they are positioned in and a rocket standing vertical in a gravity field has a gradient or depth quality.
He then states that it is in a flat field. How you get a flat field is questionable to me (my take on his claim is that the field gradient is insignifigant and is to be disregarded, not that none is there) unless you lay the rocket down but in any case he qualified it as flat and I have proceeded.
Are you saying now that depth of field has no affect or that gravity around earth has no radial depth content?
Waiting your clarification for this ever moving target.
Janus58
Valued Senior Member
Re: Tail
Just because we had a discussion about it doesn't mean you gained a complete understanding from it. The mere fact that you made the statement shows that you didn't.
I.E. My post about Clocks under acceleration and Ryan's question. Somehow you got the idea that my post was in conflict with his, yet they are in perfect agreement.
This isn't meant as a put down, But an attempt to get you to realize that you are trying to approach Relativity from a base of erroneous conceptions about it.
Just because we had a discussion about it doesn't mean you gained a complete understanding from it. The mere fact that you made the statement shows that you didn't.
I.E. My post about Clocks under acceleration and Ryan's question. Somehow you got the idea that my post was in conflict with his, yet they are in perfect agreement.
This isn't meant as a put down, But an attempt to get you to realize that you are trying to approach Relativity from a base of erroneous conceptions about it.
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Here is the problem. There are 2 kinds of people who study physics, or should I say are fascinated by physics.
First there are the people fascinated by things that happen in nature, who try to find the underlying principles behind it, and try to model it with mathematics so as the phenomena has some predictability. This is a scientist.
The second person is the person who, unhappy with the consequence that if they do not believe in God, rely on physics to give them some kind of meaning to existance, that there has to be a reason, and that some how, amongst this cataclysm of everyday chaos, that they are important, and essential in the general scheme of things. This is a philosopher.
Now I want to state something that, although you may argue to the for eons to disagree with, is a plane fact, and I've said this before;
Physics is about modelling the information that we get, and trying to explain patterns mathematically. It would be nice if the universe has some nice symmetry about it, some underlying structure that suggested the influence of some grand designer, and sweet if it does,but the universe tells us what to do, not the converse.
Physics is not the study of meaning. It will never answer the questions of being, non-being nor will give us the enlightenment of existance. It gives us understanding and predictability of things we see about us. From atoms and quarks, to galaxies and the whole Universe in general.
Theories have no physical under pinnings if we look at the foundation of its language, mathematics.
Mathematics is built up from fundemental axioms, which cannot be proved, but are considered logically concrete. Again, they cannot be proved. For example, how do you prove that the real number line is infinite in extent. You can't, it is inferred from logically concrete arguements.
Let's take Newton's second law, for every action there is an equal and opposite reaction. Prove this.
The only way is to study every sytem in the universe, which we can't. This axiom seems concrete, but all we need to do is find one counter example and it is no longer universal.
String theory is similiarly built up from what are seen as fundementally concrete axioms. But this is the current challnge for the present generation of physicists.
One more thing.
I said that one counter example needs to be found to show that a theory is no longer Universally valid. If a counter example to the postulates of SR is found i.e. the speed of light is not an upper limit to velocity, then yes SR will be proved to be no longer Universally valid. But it won't be thrown in to the theoretical junk heap as you suggest. Just as Newtons law of Gravitation was proved not to be universally true, it still explains a great deal of stuff, and NASA will still use it to calculate trajectories of its spacecraft. If SR is not universal, it will still be invaluable as look at all the phenomena it explains and predicts. It will still explain the increased half life of relativistic particles. Black holes will not suddenly become non existant. Any new theory that replaces SR(I doubt if there is any) must explain all that SR does and more.
Physics gives you understanding, not meaning.
Very Nice
ryans,
That was a well written piece and I happen to agree with it. Should v=c not be an absolute limit then that merely amends some aspects of the primary conept. It doesn't destroy it and that is my goal. To get to the truth , not to destroy what has been achieved. I think you have had a different picture of that.
Considering you commented on #1 but not #2. I am courisous if you agree with Mr Brian Greene's statement in "The Elegant Universe", regarding the different computed Pi because the ruler shrinks due to the perpeheral velocity of one measurement and the radial measurement remains constant.?
ryans,
That was a well written piece and I happen to agree with it. Should v=c not be an absolute limit then that merely amends some aspects of the primary conept. It doesn't destroy it and that is my goal. To get to the truth , not to destroy what has been achieved. I think you have had a different picture of that.
Considering you commented on #1 but not #2. I am courisous if you agree with Mr Brian Greene's statement in "The Elegant Universe", regarding the different computed Pi because the ruler shrinks due to the perpeheral velocity of one measurement and the radial measurement remains constant.?