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#1600 by TheTraveller on 10 Jan, 2017 15:27
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Monomorphic's design does not match the spherical endplate prescription you provided from Shawyer at all, and still has some RF leaking from the sides. I would expect adding sidewalls to that shape would increase the Q, since sidewalls would contain the energy that is leaking out the sides. I'd also guess that there are more different resonance modes if you added in the sidewalls, and that there might only just be the one frequency that is decently contained by Monomorphic's design.
Point being it has been shown that at these GHz frequencies, side walls are not required to restrain the photons once they form into spherical wavefronts that match the concave and convex reflecting surfaces.
Which also means that if there are side walls, sure the photons will generate eddy currents in the side walls as their E fields pass close by but they will not be bouncing off the side walls via a radiation pressure reflection as they travel between the end plate reflections. Which is what Roger claims. -
#1601 by X_RaY on 10 Jan, 2017 17:35
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Monomorphic, that's a nice catch!
Can't help but it doesn't looks like a TE013 field pattern. E should be zero along the central axis, so this is some other mode shape. Could you so kind to show E and H with field vectors please (each at the phase where the single componemt have its max amplitude)? -
#1602 by Rodal on 10 Jan, 2017 17:47
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Monomorphic, that's a nice catch!
Precisely, it does not look like a TE01p mode, therefore attributing this mode to Shawyer is inconsistent with what Shawyer has written.
Can't help but it doesn't looks like a TE013 field pattern. E should be zero along the central axis, so this is some other mode shape. Could you so kind to show E and H with field vectors please (each at the phase where the single componemt have its max amplitude)?
To me it looks this mode may be described as a superposition of transverse modes and its description may need an expansion over some complete, orthogonal set of functions such as Hermite polynomials or the Ince polynomials that satisfy Maxwell's equations and the boundary conditions, which have been changed in this case.
Hermite polynomials: https://en.wikipedia.org/wiki/Hermite_polynomials
Ince polynomials: https://en.wikipedia.org/wiki/Ince_equation
It does not make sense to describe this as a mode shape satisfying reflection boundary conditions at side walls, like TE01p, when the boundary conditions have been changed such that there are no side walls. -
#1603 by Peter Lauwer on 10 Jan, 2017 18:48
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8 W Wifi Repeater EDUP EP-AB003
I have also bought an RF amplifier such as which TheTraveller uses and measured the amplification today. As RF source I used the Windfreak SynthNV signal generator.
At 2.45 GHz I measured a (maximum) power output of the SynthNV of 16.5 dBm. This signal was fed into the Wifi repeater and a) measured with a spectrum analyzer (Agilent E4404B), b) with the network analyzer feature of the SynthNV.
a) a power output of 30.3 dBm was measured => 13.8 dB amplification (an external attenuator of 20 dB was used), so lower than the given 17 dB,
b) the Windfreak network analyzer gives ~13 dB amplification (sorry, I was lazy and took a picture of the screen with my phone).
I have ordered some preamps (the 5MHz-6GHz Broadband Low Noise Amplifier RF LNA Amp Module which was recommended on this forum) to reach the 20 dBm input for the Wifi repeater.
The bandwidth of the amplifier seems to be much broader than the given specs (2.4-2.5 GHz), especially on the low freq side.
Phil, did you ever managed to get 8 W out of this amplifier?
If I extrapolate my measurements to 20 dBm input, the output will only be 33.8 dBm (2.4 W).
That would be a pity, it is such a nice compact and cheap amplifier.
I will check tomorrow if a higher power supply voltage gives a higher gain. According to the specs, it can have up to 16 V. The small power supply delivered with the amp gives an unloaded voltage of 12.1 V, this may drop when loaded, I didn't check.
Peter,
Haven't checked the Rf amps output as still waiting on a few bits, with include a few dummy loads.
Have other irons in the Rf amp fire, so if that amp fails to deliver, there are falls back units on tap.
If forced to do so, there are several chip manufs that can provide such Rf amp chips and full PCB specs.
Most WiFi routers seem to deliver around 16-18dBm output before any antenna gain numbers, so assume that to be a starting input drive level.
Increasing the supply voltage does not help. I estimate that 34 dBm is the most we will get out of it (with 20 dBm input). The specified 8 W output is a bit optimistic/misleading/a dirty lie (whatever you prefer). -
#1604 by Monomorphic on 10 Jan, 2017 19:00
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Monomorphic, that's a nice catch!
Can't help but it doesn't looks like a TE013 field pattern. E should be zero along the central axis, so this is some other mode shape. Could you so kind to show E and H with field vectors please (each at the phase where the single componemt have its max amplitude)?
It's definitely not TE013.
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#1605 by Monomorphic on 10 Jan, 2017 19:03
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Increasing the supply voltage does not help. I estimate that 34 dBm is the most we will get out of it (with 20 dBm input). The specified 8 W output is a bit optimistic/misleading/a dirty lie (whatever you prefer).
So about 2.5 watts.
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#1606 by rfmwguy on 10 Jan, 2017 20:05
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I have one of these but never used it. Do me a favor, pulse modulate he input and tell me what peak power you see. They may have improperly stated 8W and we assumed CW. It could be a peak power rating which might still be useful to drive a final amp as long as pulse remains. Try a 100 microsecond pulse width at a slow rep rate.8 W Wifi Repeater EDUP EP-AB003
I have also bought an RF amplifier such as which TheTraveller uses and measured the amplification today. As RF source I used the Windfreak SynthNV signal generator.
At 2.45 GHz I measured a (maximum) power output of the SynthNV of 16.5 dBm. This signal was fed into the Wifi repeater and a) measured with a spectrum analyzer (Agilent E4404B), b) with the network analyzer feature of the SynthNV.
a) a power output of 30.3 dBm was measured => 13.8 dB amplification (an external attenuator of 20 dB was used), so lower than the given 17 dB,
b) the Windfreak network analyzer gives ~13 dB amplification (sorry, I was lazy and took a picture of the screen with my phone).
I have ordered some preamps (the 5MHz-6GHz Broadband Low Noise Amplifier RF LNA Amp Module which was recommended on this forum) to reach the 20 dBm input for the Wifi repeater.
The bandwidth of the amplifier seems to be much broader than the given specs (2.4-2.5 GHz), especially on the low freq side.
Phil, did you ever managed to get 8 W out of this amplifier?
If I extrapolate my measurements to 20 dBm input, the output will only be 33.8 dBm (2.4 W).
That would be a pity, it is such a nice compact and cheap amplifier.
I will check tomorrow if a higher power supply voltage gives a higher gain. According to the specs, it can have up to 16 V. The small power supply delivered with the amp gives an unloaded voltage of 12.1 V, this may drop when loaded, I didn't check.
Peter,
Haven't checked the Rf amps output as still waiting on a few bits, with include a few dummy loads.
Have other irons in the Rf amp fire, so if that amp fails to deliver, there are falls back units on tap.
If forced to do so, there are several chip manufs that can provide such Rf amp chips and full PCB specs.
Most WiFi routers seem to deliver around 16-18dBm output before any antenna gain numbers, so assume that to be a starting input drive level.
Increasing the supply voltage does not help. I estimate that 34 dBm is the most we will get out of it (with 20 dBm input). The specified 8 W output is a bit optimistic/misleading/a dirty lie (whatever you prefer). -
#1607 by Peter Lauwer on 10 Jan, 2017 20:16
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8 W Wifi Repeater EDUP EP-AB003
I have one of these but never used it. Do me a favor, pulse modulate he input and tell me what peak power you see. They may have improperly stated 8W and we assumed CW. It could be a peak power rating which might still be useful to drive a final amp as long as pulse remains. Try a 100 microsecond pulse width at a slow rep rate.
....
Increasing the supply voltage does not help. I estimate that 34 dBm is the most we will get out of it (with 20 dBm input). The specified 8 W output is a bit optimistic/misleading/a dirty lie (whatever you prefer).
OK, I will. Good idea. Probably not before the coming weekend. -
#1608 by flux_capacitor on 10 Jan, 2017 20:24
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Someone proposed an interesting thought experiment elsewhere involving gravitational redshift, similar to the Pound-Rebka experiment.
Pound and Rebka successfully measured in 1959 an effect of general relativity involving the redshift and blueshift of photons travelling in a gravitational potential, using the height of a building in Earth's gravity. When a photon moves away from the Earth, it has to "climb" the gravitational well and it is redshifted (its frequency is reduced and its wavelength increased). Conversely, when a photon falls towards Earth, it is blueshifted (its frequency is increased and its wavelength reduced).
The experiment is now transposed in deep free space, with no influence from any celestial body. Two identical perfect mirrors are attached and face each other, forming a long optical cavity. At one end of the cavity, behind one mirror, a very dense, very heavy mass is attached. The mass there creates a gravitational gradient into the cavity. A photon reflected from the mirror near the heavier side of the cavity in direction of the other mirror undergoes a gravitational redshift; while a photon reflected from this side toward the heavy side undergoes a gravitational blueshift.
So the wavelength of photons travelling inside the cavity in one direction is increased, while the wavelength of photons travelling in the other direction is reduced.
Question: do photons gain and loose energy and momentum in the process; are energy and momentum transferred to the gravitational field and in fine to the walls of the cavity and its attached mass?
In other words, will the cavity and its attached mass move forward due to the continuous shifting of photons momentum backwards?
The most accepted explanation for the Pound-Rebka experiment states the photons undergoing a gravitational red or blueshift do not loose or gain energy and momentum, because the gravitational red or blueshift is in fact a consequence of time dilation (point 3 below): the thin mirror will see a photon of lower frequency than the same photon that was emitted at the heavy mirror because their own clock (taped onto each mirror) measure time differently (the thin mirror clock is running faster than the heavy mirror clock).
But proponents of the theory of general relativity offer 5 different conflicting explanations of the Pound-Rebka experiment, that are said to be equivalent to each other and therefore all equally correct. And two of those explanations (points 1 and 2 below) posit energy and momentum are transferred from the red and blueshifted photons to the field.
Those explanations are:
1. Non-Doppler shifts due to interaction with the field
The blueshifted photons acquire inertial mass, energy and momentum from the field, while the redshifted photons loose mass, energy and momentum to the field.
The main problem with this explanation lies in the conceptualization of a physical process by which mass, momentum and energy could be either added to or subtracted from a photon without changing its velocity or angular momentum. Such a mechanism has never been proposed except for a mathematical description of a four-dimensional spacetime continuum.
This is a non-Doppler explanation of the shifts in which both source, observer and all photons are in the same inertial reference frame and the photons move at constant velocity c relative to both source and observer.
2. Doppler shifts due to the variation of the velocity of photons at constant wavelength
The velocity of photons falling into the gravitational field is increased, and the velocity of photons escaping the field is reduced, while their wavelengths stay constant. The time of travel being different, one measure Doppler shifts.
The main problem with this explanation is that it violates the constancy of the speed of light because each of the photons used is moving at a different velocity and none are moving at c relative to either source or observer.
This is a Doppler shift explanation in which both source and observer are in the same inertial reference frame and each photon is in a different inertial reference frame.
3. Non-Doppler shifts due to gravitational time dilation
Gravity causes clocks at the bottom of the tower to run slower than clocks at the top. This causes the emitter to take more time to produce a photon and thus increase its wavelength. The faster clock at the top of the tower makes the emitter produce its photons in shorter time intervals and with shorter wavelengths. While all photons move at exactly c in this example, the observer at the top of the tower would measure their velocity to be less than c and the observer at the bottom of the tower would measure their velocity to be greater than c. This is due to their clocks running at different rates. If both emitters are set to produce photons with the same time intervals between them, the top emitter will produce more photons per second than the emitter at the bottom.
But this explanation, while correct, produces and effect far too small to account for the Pound-Rebka results. The only explanation of this effect that is compatible with the Equivalence Principle is that this clock slowing at sea level is a relativistic time dilation caused by the Earth's escape velocity at the clock's location.
4. Doppler shifts due to observers acceleration
Only the measuring instruments are judge and the results are not reinterpreted to fit the metaphysical assumption of the Equivalence Principle. Accelerometers placed at the top and bottom of the tower measure an upward acceleration greater at the seal level. All the photons move at exactly c within the same inertial reference frame common to all other photons. The accelerometers show that in the time taken for the photons to travel between source and observer, both observers have accelerated upward. This relative velocity between source and observer causes the descending photons to be measured with shorter wavelengths and the ascending photons to be measured with longer wavelengths.
5. Doppler shifts due to 4D spacetime continuum
The gravitational interaction occurs within a four dimensional spacetime continuum that cannot be illustrated by drawings and can only be understood in terms of non-Euclidean geometry. The claim is made that gravity causes this spacetime to curve in a non-intuitive way that cannot be visualized. As the photons move through this curved space, they acquire its curvature and are thus measured to be red and blue shifted. While there are no experimental measurements that could serve as evidence for "the spacetime continuum" a prior belief in the Equivalence Principle allows one to suspend belief in physical measurement and say that acceleration exists where it cant be measured (falling bodies) and it is measured where it doesn't exist (Earth's surface).
Note Shawyer talks about momentum exchange between the photons and the cavity through a wavelength variation like in explanation (1) but says something like explanation (2) "both source and observer are in the same inertial reference frame and each photon is in a different inertial reference frame".
Source: Just Which Equivalence Principle Do You Believe In?
The picture shows Glen Rebka at the lower end of a tower of the Jefferson Physical Laboratory, Harvard University, 1959.
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#1609 by WarpTech on 10 Jan, 2017 23:55
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Someone proposed an interesting thought experiment elsewhere involving gravitational redshift, similar to the Pound-Rebka experiment.
Pound and Rebka successfully measured in 1959 an effect of general relativity involving the redshift and blueshift of photons travelling in a gravitational potential, using the height of a building in Earth's gravity. When a photon moves away from the Earth, it has to "climb" the gravitational well and it is redshifted (its frequency is reduced and its wavelength increased). Conversely, when a photon falls towards Earth, it is blueshifted (its frequency is increased and its wavelength reduced).
The experiment is now transposed in deep free space, with no influence from any celestial body. Two identical perfect mirrors are attached and face each other, forming a long optical cavity. At one end of the cavity, behind one mirror, a very dense, very heavy mass is attached. The mass there creates a gravitational gradient into the cavity. A photon reflected from the mirror near the heavier side of the cavity in direction of the other mirror undergoes a gravitational redshift; while a photon reflected from this side toward the heavy side undergoes a gravitational blueshift.
So the wavelength of photons travelling inside the cavity in one direction is increased, while the wavelength of photons travelling in the other direction is reduced.
Question: do photons gain and loose energy and momentum in the process; are energy and momentum transferred to the gravitational field and in fine to the walls of the cavity and its attached mass?
In other words, will the cavity and its attached mass move forward due to the continuous shifting of photons momentum backwards?
...
Excellent review! This is a very confusing issue for many, many people. I think it is much simpler to view it in terms of the PV Model of GR, where we model the gravitational field as a variable speed of light, determined by a variable refractive index, K. So the speed of light becomes;
c => c0/K,
where in spherical coordinates;
K = (1 - 2GM/rc02)-1
i.e., the Schwarzschild potential, where r is measured from the CM, and M is the mass, such as the Earth, or the "very dense, very heavy mass" attached to the mirror.
In this representation, K is what is seen by a "distant observer", far from the effects of the gravitational field. In the frame of the distant observer, K = 1. Relative to his location, K > 1 in any gravitational field.
From his perspective, the heavy mirror emits a photon of momentum p1 and feels a recoil -p1.
The photon arrives at the light mirror with momentum p1 and the mirror absorbs p1.
Then the light mirror emits a photon of momentum -p2 and feels a recoil p2, where |p2| > |p1|.
The photon arrives at the heavy mirror with momentum -p2 and the mirror absorbs -p2.
Therefore, the momentum is balanced and nothing moves.
In the frame of a distant observer looking down into a gravity well, he sees the clock down there is running slow. So from this perspective, the photon is emitted "red-shifted", it doesn't change along the path. The confusion starts when people jump between the distant observer frame and the local frame. They are NOT the same. It is much easier to analyze from the distant observer's perspective. -
#1610 by dustinthewind on 11 Jan, 2017 01:10
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You state that the photon travels away from a gravitational object leaving the heavy mirror and arrives at the light mirror. So it climbed out of the gravity well but some how retained it's momentum? How so? If we fired a cannonball on the moon and it rose to a new height wouldn't it lose momentum also? Also doesn't this change in momentum and time (1 and 2) happen over the distance traveled and not solely at the point of reflection?Someone proposed an interesting thought experiment elsewhere involving gravitational redshift, similar to the Pound-Rebka experiment.
Pound and Rebka successfully measured in 1959 an effect of general relativity involving the redshift and blueshift of photons travelling in a gravitational potential, using the height of a building in Earth's gravity. When a photon moves away from the Earth, it has to "climb" the gravitational well and it is redshifted (its frequency is reduced and its wavelength increased). Conversely, when a photon falls towards Earth, it is blueshifted (its frequency is increased and its wavelength reduced).
The experiment is now transposed in deep free space, with no influence from any celestial body. Two identical perfect mirrors are attached and face each other, forming a long optical cavity. At one end of the cavity, behind one mirror, a very dense, very heavy mass is attached. The mass there creates a gravitational gradient into the cavity. A photon reflected from the mirror near the heavier side of the cavity in direction of the other mirror undergoes a gravitational redshift; while a photon reflected from this side toward the heavy side undergoes a gravitational blueshift.
So the wavelength of photons travelling inside the cavity in one direction is increased, while the wavelength of photons travelling in the other direction is reduced.
Question: do photons gain and loose energy and momentum in the process; are energy and momentum transferred to the gravitational field and in fine to the walls of the cavity and its attached mass?
In other words, will the cavity and its attached mass move forward due to the continuous shifting of photons momentum backwards?
...
Excellent review! This is a very confusing issue for many, many people. I think it is much simpler to view it in terms of the PV Model of GR, where we model the gravitational field as a variable speed of light, determined by a variable refractive index, K. So the speed of light becomes;
c => c0/K,
where in spherical coordinates;
K = (1 - 2GM/rc02)-1
i.e., the Schwarzschild potential, where r is measured from the CM, and M is the mass, such as the Earth, or the "very dense, very heavy mass" attached to the mirror.
In this representation, K is what is seen by a "distant observer", far from the effects of the gravitational field. In the frame of the distant observer, K = 1. Relative to his location, K > 1 in any gravitational field.
From his perspective, the heavy mirror emits a photon of momentum p1 and feels a recoil -p1.
The photon arrives at the light mirror with momentum p1 and the mirror absorbs p1.
Then the light mirror emits a photon of momentum -p2 and feels a recoil p2, where |p2| > |p1|.
The photon arrives at the heavy mirror with momentum -p2 and the mirror absorbs -p2.
Therefore, the momentum is balanced and nothing moves.
In the frame of a distant observer looking down into a gravity well, he sees the clock down there is running slow. So from this perspective, the photon is emitted "red-shifted", it doesn't change along the path. The confusion starts when people jump between the distant observer frame and the local frame. They are NOT the same. It is much easier to analyze from the distant observer's perspective.
1. Also, I know a photon created at low height (greater gravity) osculates at a slower frequency but should speed up in frequency as it leaves the gravity well right? That is the effect due to existing in the gravity well leaves when you depart from that field and time increases.
2. However the effect of losing energy to escape the gravity field make the two effects seemingly different from or opposed to each other. Effect 2 should cause a loss of frequency as it escapes which is opposite of effect 1. Effect 2 might be thought of as just the energy lost to escape the gravity well while effect 1 seems to be related to the PV effect or relativity....
I would be curious if they accounted for both effect 1 and effect 2. I.e. effect 1 opposes effect 2 perfectly so no change? Oddly the equations for the polarizable vacuum (PV=effect1?) seem to suggest light leaving or entering a gravitational field change in both momentum and energy and if I remember correctly what is preserved or constant=Momentum*Energy.
The most accepted explanation for the Pound-Rebka experiment states the photons undergoing a gravitational red or blueshift do not loose or gain energy and momentum, because the gravitational red or blueshift is in fact a consequence of time dilation (point 3 below): the thin mirror will see a photon of lower frequency than the same photon that was emitted at the heavy mirror because their own clock (taped onto each mirror) measure time differently (the thin mirror clock is running faster than the heavy mirror clock).
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#1611 by dustinthewind on 11 Jan, 2017 01:29
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I don't trust the differences between the air bearing test and spring test because the configurations are so different and air convection was not eliminated in those experiments. Convection flow on the spring scale may have been completely different on than on the air bearing test. Even if there was an effect would it be masked by hot air flow on the outside?It reads to me like an attempt to satisfy Newton (every action must have an equal and opposite reaction) without an understanding of what that really means in this context.
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Todd, please carefully go over my message and you will see that it is not as simple as that. Even if you change "thrust' by "reaction" the contradictions between NASA and Shawyer do NOT disappear.
Jose,
Shawyer uses the term "Thrust" to mean the direction of the exhaust and "Reaction" to mean the direction of the rocket. Everyone else on this forum uses the term "Thrust" to mean the direction of the rocket. Pauls answer and Shawyer's agree, but his British terminology is bassackwards!
If you want to really dig the subject, it is indeed more complicated than that.
Primarily because Shawyer experimentally measured a thrust force (small to big end) on a composite spring balance, and a reaction force (big to small end) on an air bearing rotary test rig, for the same frustum. So it's not only just "wording to account for Newton's law".
Then because he also claims that if only the reaction force is measurable on a "free-to-accelerate" frustum, a perfectly static rig with no vibration would detect absolutely no force as the reaction and thrust forces would perfectly cancel out. The center of mass of the frustum has to be displaced, even on a very small distance (for example because of the metal elongation of the frustum due to the heat produced by RF power), and if the frustum is tied on either side by two load cells of different spring cosntants K1 and K2, then on such a static rig, the direction of the force can either be recorded as "thrust" or as "reaction", depending on which of the two spring constants K1 or K2 is the greatest!
See A Note on the Principles of EmDrive force measurement on Shawyer's website.
We have already discussed this without coming to a successful conclusion.
To do a free to accelerate and a non-free to accelerate test I would hang it from a pendulum arm and lock the arm in place for the non-free to accelerate test (if not locking the arm you could use constant thrust and measure the angular displacemnt of the arm or if locking the arm use an interferometer effect to measure warping of the arm. Then I would unlock the arm and do the free to accelerate test by pulsing the thrust as the resonant frequency of the pendulum to get max amplitude. The configurations would be almost identical and possibly eliminate the reversal effect.
TT's latest test may be optimal because it is a sort of a pendulum. With counter torque in the fiber, he can give it constant thrust and observe the angular displacement for non-free to accelerate thrust at equilibrium.
For free to accelerate thrust TT can pulse the EM drive thrust at the resonant frequency of his pendulum for maximum displacement and free to accelerate thrust.
He appears to also have plans to eliminate air convection.
Such a test would probably prove such a counter effect doesn't exist for pushing the cavity in opposite directions depending on how it is measured. -
#1612 by WarpTech on 11 Jan, 2017 01:41
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...
You state that the photon travels away from a gravitational object leaving the heavy mirror and arrives at the light mirror. So it climbed out of the gravity well but some how retained it's momentum? How so? If we fired a cannonball on the moon and it rose to a new height wouldn't it lose momentum also? Also doesn't this change in momentum and time (1 and 2) happen over the distance traveled and not solely at the point of reflection?
In this representation, K is what is seen by a "distant observer", far from the effects of the gravitational field. In the frame of the distant observer, K = 1. Relative to his location, K > 1 in any gravitational field.
From his perspective, the heavy mirror emits a photon of momentum p1 and feels a recoil -p1.
The photon arrives at the light mirror with momentum p1 and the mirror absorbs p1.
Then the light mirror emits a photon of momentum -p2 and feels a recoil p2, where |p2| > |p1|.
The photon arrives at the heavy mirror with momentum -p2 and the mirror absorbs -p2.
Therefore, the momentum is balanced and nothing moves.
In the frame of a distant observer looking down into a gravity well, he sees the clock down there is running slow. So from this perspective, the photon is emitted "red-shifted", it doesn't change along the path. The confusion starts when people jump between the distant observer frame and the local frame. They are NOT the same. It is much easier to analyze from the distant observer's perspective.
1. Also, I know a photon created at low height (greater gravity) osculates at a slower frequency but should speed up in frequency as it leaves the gravity well right? That is the effect due to existing in the gravity well leaves when you depart from that field and time increases.
2. However the effect of losing energy to escape the gravity field make the two effects seemingly different from or opposed to each other. Effect 2 should cause a loss of frequency as it escapes which is opposite of effect 1. Effect 2 might be thought of as just the energy lost to escape the gravity well while effect 1 seems to be related to the PV effect or relativity....
I would be curious if they accounted for both effect 1 and effect 2. I.e. effect 1 opposes effect 2 perfectly so no change? Oddly the equations for the polarizable vacuum (PV=effect1?) seem to suggest light leaving or entering a gravitational field change in both momentum and energy and if I remember correctly what is preserved or constant=Momentum*Energy.
The most accepted explanation for the Pound-Rebka experiment states the photons undergoing a gravitational red or blueshift do not loose or gain energy and momentum, because the gravitational red or blueshift is in fact a consequence of time dilation (point 3 below): the thin mirror will see a photon of lower frequency than the same photon that was emitted at the heavy mirror because their own clock (taped onto each mirror) measure time differently (the thin mirror clock is running faster than the heavy mirror clock).
...
It's not what you think. Please re-read my last paragraph above...
What you are describing as 1), is the behavior of the clock, not the photon. If photons behaved this way, then the distant observer would see the photons blue shift as they leave the gravity well, (gaining energy from nothing), and what arrives in the distant frame are not red photons, but blue photons. That's NOT what we observe!
Lifting the clock to a higher altitude, requires doing work on the clock. This fact is what makes objects with rest-mass different than photons. Photons go "up" along a null geodesic, because light ALWAYS travels on a null geodesic. There is no work done and none required. Lifting matter uphill against gravity, is not along a null geodesic. Work must be done to increase its energy, which is seen as an increase in its rate. -
#1613 by dustinthewind on 11 Jan, 2017 02:00
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in reference to this post here: https://forum.nasaspaceflight.com/index.php?topic=41732.msg1628028#msg1628028
You are correct. 20% is necessary to visually see the traveling wave in this plot though. a 20% amplitude can be easily observed but not much smaller, such as .1%.
I think your value of "b=0.8" is several orders of magnitude too large. In one bounce, the frequency is barely going to change. It's not going to shift 20%!
The equation seems ok I guess. For the waves: A*sin(w*t+k*x) and A*sin(w*b*t-k*b*x) and variables: A=0.5, w=pi, k=pi , b=0.8 I get the image: "FreqChangeOppositeMovingWaves.gif" attached below. The red one lost some energy so there should be a traveling wave in the direction energy is lost and there is. The image of the waves superimposed is: "FreqChangeSemiTravelWave1.gif" attached below. Now at the large amplitudes it looks like a standing wave but at about 20% amplitude you can see the wave traveling. This is a similar effect to the superimposed waves where one wave lost amplitude but this model is a loss in frequency. It seems both frequency loss or amplitude loss can set up a semi-traveling wave.
I was driving and it struck me that % as large as well maybe not quite 20% but significant none the less may be possible. How so? Consider if light at one end of the cavity changes in mass with respect to the other side of the cavity. This changes the ratio of energy exchanged between the light in what I call Doppler effect # 2 derived in my paper here: EM drive decelerating light. Part 2 of equation 14 for df/f=2*c^3(f*h/c^2)/(m2*(c+v2)^3=~2*mp/mo for low velocity where mp=effective mass of photon and mo=mass of object so unlike the doppler effect this doppler shift has a mass ratio.
By definition of momentum conservation and energy conservation if we change the mass between objects colliding we change the energy exchanged between them. If that mass changes with respect to the side of the cavity the photon can not retain its energy.
So at the big end of the cavity light strikes and loses .01% of its energy to accelerating the cavity. This is probably too large but meh. When striking the narrow end of the cavity (or somewhere along the walls) it should regain its energy but it can't because its mass changes due to a change in wavelength so lets say it regains 0.005% of its energy.
Let us say the light can complete 5,000 cycles before it is rejected from the cavity for changing in frequency too much. If this were possible this would give us a change in energy of the light by df/f=h*df/(h*f)=dE/E of 25% which would actually be significant. It also suggest why Q and bandwidth may be important. -
#1614 by dustinthewind on 11 Jan, 2017 02:25
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You state that the photon travels away from a gravitational object leaving the heavy mirror and arrives at the light mirror. So it climbed out of the gravity well but some how retained it's momentum? How so? If we fired a cannonball on the moon and it rose to a new height wouldn't it lose momentum also? Also doesn't this change in momentum and time (1 and 2) happen over the distance traveled and not solely at the point of reflection?
In this representation, K is what is seen by a "distant observer", far from the effects of the gravitational field. In the frame of the distant observer, K = 1. Relative to his location, K > 1 in any gravitational field.
From his perspective, the heavy mirror emits a photon of momentum p1 and feels a recoil -p1.
The photon arrives at the light mirror with momentum p1 and the mirror absorbs p1.
Then the light mirror emits a photon of momentum -p2 and feels a recoil p2, where |p2| > |p1|.
The photon arrives at the heavy mirror with momentum -p2 and the mirror absorbs -p2.
Therefore, the momentum is balanced and nothing moves.
In the frame of a distant observer looking down into a gravity well, he sees the clock down there is running slow. So from this perspective, the photon is emitted "red-shifted", it doesn't change along the path. The confusion starts when people jump between the distant observer frame and the local frame. They are NOT the same. It is much easier to analyze from the distant observer's perspective.
1. Also, I know a photon created at low height (greater gravity) osculates at a slower frequency but should speed up in frequency as it leaves the gravity well right? That is the effect due to existing in the gravity well leaves when you depart from that field and time increases.
2. However the effect of losing energy to escape the gravity field make the two effects seemingly different from or opposed to each other. Effect 2 should cause a loss of frequency as it escapes which is opposite of effect 1. Effect 2 might be thought of as just the energy lost to escape the gravity well while effect 1 seems to be related to the PV effect or relativity....
I would be curious if they accounted for both effect 1 and effect 2. I.e. effect 1 opposes effect 2 perfectly so no change? Oddly the equations for the polarizable vacuum (PV=effect1?) seem to suggest light leaving or entering a gravitational field change in both momentum and energy and if I remember correctly what is preserved or constant=Momentum*Energy.
The most accepted explanation for the Pound-Rebka experiment states the photons undergoing a gravitational red or blueshift do not loose or gain energy and momentum, because the gravitational red or blueshift is in fact a consequence of time dilation (point 3 below): the thin mirror will see a photon of lower frequency than the same photon that was emitted at the heavy mirror because their own clock (taped onto each mirror) measure time differently (the thin mirror clock is running faster than the heavy mirror clock).
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It's not what you think. Please re-read my last paragraph above...
What you are describing as 1), is the behavior of the clock, not the photon. If photons behaved this way, then the distant observer would see the photons blue shift as they leave the gravity well, (gaining energy from nothing), and what arrives in the distant frame are not red photons, but blue photons. That's NOT what we observe!
Lifting the clock to a higher altitude, requires doing work on the clock. This fact is what makes objects with rest-mass different than photons. Photons go "up" along a null geodesic, because light ALWAYS travels on a null geodesic. There is no work done and none required. Lifting matter uphill against gravity, is not along a null geodesic. Work must be done to increase its energy, which is seen as an increase in its rate.
I see what your saying is that light emitted from a gravitational surface, is not being effected by the gravity, so needs no energy to escape gravity, so is not red-shifted to escape the gravity well, having no mass.
Beyond that, it appears your saying that the light is not even effected by the gravity well gradient in space so the frequency it is emitted at remains its frequency permanently. So light emitted in the gravity well, in slow time, remains slow in frequency, even having left its gravitational well.
I get it, but I still have some conceptual problems with this. How then if gravity has no effect on such photons escaping a gravity well, does gravity even bend light? We can't slow time for them, so when encountering a gravity well in space they don't encounter increased resistance due to slower time. When passing a gravity well they feel no tug of the gravity well because they have no mass.
No only this but gravity is mutual between to masses. A beam pulse of light is emitted such that it has an equivalent mass to gravitationally attract as it passes a planet. But by what I am getting from you it appears the planet would be attracted to the light but not the light to the planet(neutron star) ect because light is not effected by the gravity well. How does light have no effective mass if energy has equivalence to mass.
Also how do we know for sure that light emitted from the distant universe isn't escaping some amazing gravitational attraction such that it lost energy from that [effect 2]? I.e. some event horizon that was responsible for the creation of the universe which we exist inside of and is what is supposedly accelerating the universe now is actually such a collapse as in a reverse big bang.
Or that light escaping from a gravitational surface actually loses energy to gravity, as in escape velocity [effect 2], (slows down red-shifts it/parallel line of thinking) and it's time actually increases as it climbs out [effect 1] but that effect being less than the energy required to climb out [effect 1 < effect 2] resulting in an overall red-shift or loss of energy. -
#1615 by WarpTech on 11 Jan, 2017 02:47
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It's not what you think. Please re-read my last paragraph above...
What you are describing as 1), is the behavior of the clock, not the photon. If photons behaved this way, then the distant observer would see the photons blue shift as they leave the gravity well, (gaining energy from nothing), and what arrives in the distant frame are not red photons, but blue photons. That's NOT what we observe!
Lifting the clock to a higher altitude, requires doing work on the clock. This fact is what makes objects with rest-mass different than photons. Photons go "up" along a null geodesic, because light ALWAYS travels on a null geodesic. There is no work done and none required. Lifting matter uphill against gravity, is not along a null geodesic. Work must be done to increase its energy, which is seen as an increase in its rate.
I see what your saying is that light emitted from a gravitational surface, is not being effected by the gravity, so needs no energy to escape gravity, so is not red-shifted to escape the gravity well, having no mass.
Beyond that, it appears your saying that the light is not even effected by the gravity well gradient in space so the frequency it is emitted at remains its frequency permanently. So light emitted in the gravity well, in slow time, remains slow in frequency, even having left its gravitational well.
I get it, but I still have some conceptual problems with this. How then if gravity has no effect on such photons escaping a gravity well, does gravity even bend light? We can't slow time for them, so when encountering a gravity well in space they don't encounter increased resistance due to slower time. When passing a gravity well they feel no tug of the gravity well because they have no mass.
No only this but gravity is mutual between to masses. A beam pulse of light is emitted such that it has an equivalent mass to gravitationally attract as it passes a planet. But by what I am getting from you it appears the planet would be attracted to the light but not the light to the planet(neutron star) ect because light is not effected by the gravity well. How does light have no effective mass if energy has equivalence to mass.
Also how do we know for sure that light emitted from the distant universe isn't escaping some amazing gravitational attraction such that it lost energy from that [effect 2]? I.e. some event horizon that was responsible for the creation of the universe which we exist inside of and is what is supposedly accelerating the universe now is actually such a collapse as in a reverse big bang.
Or that light escaping from a gravitational surface actually loses energy to gravity, as in escape velocity [effect 2], (slows down red-shifts it/parallel line of thinking) and it's time actually increases as it climbs out [effect 1] but that effect being less than the energy required to climb out [effect 1 < effect 2] resulting in an overall red-shift or loss of energy.
This is why GR is a geometric interpretation. To answer your question, you must calculate the null geodesics for the planet, or mass distribution the light is passing through. The light is not bent. It is traveling in a straight line, and it is space-time that is bent.
This is why I am working on my model using Damping of the oscillators as the gravitational potential. Using a refractive index is a nice, easy way to describe things, but it leads to confusion because while we can interpret that as a variable speed of light, it really applies to the clocks and rulers, not the light itself. Light ALWAYS travels on null geodesics.
Note, I have just come to grips with this myself recently. Your posts prompted this, because it was not clear to me until I realized after watching Dr. Fern's video that; null geodesics do not change. Their path through space-time has "zero" length, and no work is done along this path. So the photons cannot, and do not change. Matter on the other hand, does change and it requires work to be done to change it. So the K in our PV Model, is really about altering matter, not light. Hence, why I prefer to use Damping (Zeta) rather than K now, in my model and the paper I'm slowly putting together.
Also, IMO with respect to cosmology. It is our local ruler that is contracting at a rate of 6.8 nanometers per meter, per century. Matter is condensing and entropy continues to increase as matter cools and contracts, but space is probably not expanding. The Friedmann equations scale factor "a" can be taken either way. The two views are reciprocal. Space is expanding, or rulers are contracting. Same diff.
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#1616 by dustinthewind on 11 Jan, 2017 03:21
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Yeah me suggesting the big bang in reverse (hole is outside not us) and now that (reverse big bang is now contracting) universe appears to accelerate may actually be collapse of reverse big bang or space being stretched due to acceleration by horizon or our rulers shrinking with respect to stretched space so maybe were on same page. Not the best thought but meh.It's not what you think. Please re-read my last paragraph above...
What you are describing as 1), is the behavior of the clock, not the photon. If photons behaved this way, then the distant observer would see the photons blue shift as they leave the gravity well, (gaining energy from nothing), and what arrives in the distant frame are not red photons, but blue photons. That's NOT what we observe!
Lifting the clock to a higher altitude, requires doing work on the clock. This fact is what makes objects with rest-mass different than photons. Photons go "up" along a null geodesic, because light ALWAYS travels on a null geodesic. There is no work done and none required. Lifting matter uphill against gravity, is not along a null geodesic. Work must be done to increase its energy, which is seen as an increase in its rate.
I see what your saying is that light emitted from a gravitational surface, is not being effected by the gravity, so needs no energy to escape gravity, so is not red-shifted to escape the gravity well, having no mass.
Beyond that, it appears your saying that the light is not even effected by the gravity well gradient in space so the frequency it is emitted at remains its frequency permanently. So light emitted in the gravity well, in slow time, remains slow in frequency, even having left its gravitational well.
I get it, but I still have some conceptual problems with this. How then if gravity has no effect on such photons escaping a gravity well, does gravity even bend light? We can't slow time for them, so when encountering a gravity well in space they don't encounter increased resistance due to slower time. When passing a gravity well they feel no tug of the gravity well because they have no mass.
No only this but gravity is mutual between to masses. A beam pulse of light is emitted such that it has an equivalent mass to gravitationally attract as it passes a planet. But by what I am getting from you it appears the planet would be attracted to the light but not the light to the planet(neutron star) ect because light is not effected by the gravity well. How does light have no effective mass if energy has equivalence to mass.
Also how do we know for sure that light emitted from the distant universe isn't escaping some amazing gravitational attraction such that it lost energy from that [effect 2]? I.e. some event horizon that was responsible for the creation of the universe which we exist inside of and is what is supposedly accelerating the universe now is actually such a collapse as in a reverse big bang.
Or that light escaping from a gravitational surface actually loses energy to gravity, as in escape velocity [effect 2], (slows down red-shifts it/parallel line of thinking) and it's time actually increases as it climbs out [effect 1] but that effect being less than the energy required to climb out [effect 1 < effect 2] resulting in an overall red-shift or loss of energy.
This is why GR is a geometric interpretation. To answer your question, you must calculate the null geodesics for the planet, or mass distribution the light is passing through. The light is not bent. It is traveling in a straight line, and it is space-time that is bent.
This is why I am working on my model using Damping of the oscillators as the gravitational potential. Using a refractive index is a nice, easy way to describe things, but it leads to confusion because while we can interpret that as a variable speed of light, it really applies to the clocks and rulers, not the light itself. Light ALWAYS travels on null geodesics.
Note, I have just come to grips with this myself recently. Your posts prompted this, because it was not clear to me until I realized after watching Dr. Fern's video that; null geodesics do not change. Their path through space-time has "zero" length, and no work is done along this path. So the photons cannot, and do not change. Matter on the other hand, does change and it requires work to be done to change it. So the K in our PV Model, is really about altering matter, not light. Hence, why I prefer to use Damping (Zeta) rather than K now, in my model and the paper I'm slowly putting together.
Also, IMO with respect to cosmology. It is our local ruler that is contracting at a rate of 6.8 nanometers per meter, per century. Matter is condensing and entropy continues to increase as matter cools and contracts, but space is probably not expanding. The Friedmann equations scale factor "a" can be taken either way. The two views are reciprocal. Space is expanding, or rulers are contracting. Same diff.
This paper here: http://home.fnal.gov/~syphers/Education/Notes/lightbend.pdf if you read it they predict the bending of light using space time but the equations suggest a change in velocity of light by change in space and time, possibly suggesting light is effected by time and space as is matter? Or maybe they are using antiquated equations but it give the correct prediction of the bending of light 4GM/ect instead of 2GM/ect.
It is also tempting to imagine the wavelength of light contracting as it falls into a black hole. Space shrinking and time slowing such that light becomes part of the growing event horizon adding to the thickness of the event as energy collects on its surface and comes to a stop.
I understand where your coming from but its hard for me to accept. I'll keep an open mind to both possibilities though. -
#1617 by M.LeBel on 11 Jan, 2017 03:35
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I think I figured where to place the antenna in the amphora cavity. We place the antenna inside the tapered neck at the cut-off diameter, or slightly before cut-off. Much dissipation will occur beyond the cut-off diameter, which section is required. (Warptech: antenna near the cut-off diameter would provide dissipation on one side and emission on the other?)
Anyone wanting to try the sims? All dimensions as illustrated refer/proportional to the cut-off diameter. Curvatures optimized for best reflections. Copper and your best GHz value. Just a hunch for now. (Well, slowly heading for the causal structure...John Newell complex time might solve this)
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#1618 by WarpTech on 11 Jan, 2017 05:11
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This paper here: http://home.fnal.gov/~syphers/Education/Notes/lightbend.pdf if you read it they predict the bending of light using space time but the equations suggest a change in velocity of light by change in space and time, possibly suggesting light is effected by time and space as is matter? Or maybe they are using antiquated equations but it give the correct prediction of the bending of light 4GM/ect instead of 2GM/ect.
It is also tempting to imagine the wavelength of light contracting as it falls into a black hole. Space shrinking and time slowing such that light becomes part of the growing event horizon adding to the thickness of the event as energy collects on its surface and comes to a stop.
I understand where your coming from but its hard for me to accept. I'll keep an open mind to both possibilities though.
The paper has the correct equations. Schwarzschild's equation is an exact solution. The last equation is just a coordinate transformation. I think the confusion is between light that is propagating radially outward, vs light that is propagating transversely through the field. In both cases, light is following along a null geodesic, but in the case of the transverse path, it can be "modeled" as a refractive index, in the Newtonian sense. However, one must realize and understand that no work is being done to either the photons or the planet as they pass one another.
In your last statement, light falling into a black hole is a matter of perspective. You said "space shrinking", which is backwards. Space appears to stretch, rulers (matter) appear to shrink. They are reciprocals in the metric.
The distant observer cannot observe what happens at the event horizon because the matter there does not appear to oscillate. Time appears to have stopped. All oscillators have become critically damped and light can't be emitted, from this perspective.
I advise you to adjust your thinking, so that you think ONLY in terms of rulers and clocks (oscillators) as the variables. Not space and time. Space and time don't do anything outside of what we measure with rulers and clocks. There is no absolute measurement. Everything, has a relative scale and K is the scaling factor.
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#1619 by spupeng7 on 11 Jan, 2017 05:58
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On the subject of conceptual difficulties, Spacetime
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That remains a distraction, what we should at least consider is that Einstein was not considering gravity or inertia as consequences of direct electrical interaction between all charges. Complex time allows that possibility and it is my conviction that it should be further investigated now that we have evidence supporting Mach's notion that inertia does depend upon a mutual interaction of matter.
John Newell..
In my view, if there is no effect to be measured, then there is no effect and therefore, it doesn't need to exist.
What sort of "clock" can be used to measure your "complex time"? IMO, clocks are just something to which we can compare other processes to. Nothing more. IMO, complex numbers are just a fancy way to represent phase differences, or phase shifts but only have meaning when comparing one thing to another thing. So my question above pertains to what do you use and what do you compare to, to measure this complex time.
Thank you.
WarpTech,
clocks measure the scalar component of time which only remains true for a single, roughly symmetrical, surface about a center of gravity. Meantime time progresses at different rates everywhere else and this reveals a complex structure that seems obvious to me. The complex conjugate of a measurement of time is all those places where charges reside which are at the speed of light in any direction from the origin of the measurement.
This describes a very different mechanism for electromagnetic interaction, a mechanism which does not require photons to exist outside of the single moment of complex time in which they reside. This is not simply a phase difference, it is utterly different conceptually. This gives us a mechanism of action by which all charges may interact. It shows us an emdrive frustum which remains empty but for electron excitement in its reflectors and sidewalls. It gives us a potential mechanism of action for the thrust produced, without local equal and opposite reaction.
The opinion is forming in my mind that what we know as photons are resonant interactions across complex time, across those spaces where charges reside at the speed of light in any direction from the charge they are resonant with. Gravity and inertia would then be simple electrical interactions between all charges, not resonant at other than their orbital period or circumstantial motions, interactions between charges separated by the speed of light between them.
This is a very different cosmology and I appreciate that my explanations are far from adequate so I thank anyone who has the patience to absorb them and appeal for assistance with forming a more stable conceptualization about them. JMN..
(modified to remove redundant 'is' from first sentence & add 'between all charges' to paragraph 3 :-)
