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Author Topic: Do we need to rethink gravitational red shift?  (Read 3740 times)

Offline Vern

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Do we need to rethink gravitational red shift?
« on: 09/11/2009 15:08:02 »
Light experiences a red shift due to the affect of gravity. The effect is cumulative, so that once shifted, the light does not return to its previous frequency. There seems to be much more gravity in space than is accounted for by the things we can see. Now that we have a measure for this increased amount of gravity, do we need to rethink what effect this extra gravity has upon light?

It is easy to see that light climbing out of a gravity well would be red shifted. Light plunging into a gravity well would be blue shifted. But the question here is about ambient gravity. Ambient gravity would be like the gravity balance at the common point that orbiting objects revolve around. Does ambient gravity produce a red shift?





« Last Edit: 09/11/2009 20:28:52 by Vern »


 

Offline Mr. Scientist

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Re: Do we need to rethink gravitational red shift?
« Reply #1 on: 09/11/2009 16:14:18 »
I would imagine that these things will be re-modelled a few times before any final theory is deducted. Oh indeed, physics has many changes yet to go, that much most scientists agree on :)
 

Offline Geezer

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Re: Do we need to rethink gravitational red shift?
« Reply #2 on: 09/11/2009 19:20:48 »
Interesting question Vern. :)

As I understand it (someone please correct me if this is wrong) much of our current understanding of the amount of matter in the Universe is based on the "motion" of galaxies. I put motion in quotes because we cannot directly measure the speed of other other galaxies relative to our galaxy; we infer their movement based on the spectrum shift (red shift) we observe in the light we receive from them.

So, if our understanding of red shift is a bit "off" it will throw a cosmic monkey wrench in our understanding of movements of galaxies which, in turn, will cause us to revise our estimates for the amount of matter in the Universe.
 

Offline Vern

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Re: Do we need to rethink gravitational red shift?
« Reply #3 on: 09/11/2009 20:03:17 »
Does anybody have a guess about whether ambient gravity produces a red shift?

Quote from: OP
Ambient gravity would be like the gravity balance at the common point that orbiting objects revolve around. Does ambient gravity produce a red shift?

My speculation is that it does; but I am not sure if everyone is even in agreement that ambient gravity is a valid concept.




 

Offline Mr. Scientist

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Re: Do we need to rethink gravitational red shift?
« Reply #4 on: 09/11/2009 20:15:05 »
Does anybody have a guess about whether ambient gravity produces a red shift?

I actually don't Vern. I would imagine it can have that property, since there is the ambient gravitational field.
 

Offline Vern

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Do we need to rethink gravitational red shift?
« Reply #5 on: 09/11/2009 20:36:58 »
I did some speculating about what might cause photon red shift in ambient gravity. I'm not sure if there is any validity to the notion or not. I thought that there might be an argument that gravity cancels out so that at the point of equilibrium between gravitating bodies, there would be zero gravity instead of an ambient amount. If it is gravitons, or if it is photons, there would be ambient gravity.


Quote from: the link
Consider that diminished electromagnetic fields from photons permeate all of space, even that space that is inside matter. The reason the fields can permeate all space is that they are too weak to interact and so are almost invisible to matter. Photons moving  through these diminished fields reach their saturation amplitude with the help of the fields. Saturation amplitude is therefore reached at an offset toward increasing field strength of the diminished fields. That is gravity according to photon-theory.

Now, with that understanding we are faced with a new realization. The photon needs to transition through less overall amplitude to become saturated. This means that the peak to peak amplitude transition of the photon is less in a gravity field than it is outside the gravity field. Less peak to peak amplitude means less energy. So, a photon must lose energy to an ambient gravity field.

This loss of energy must manifest itself as a shift in wavelength. The red shift is accumulative, so that once shifted the photon does not regain its lost energy. Some areas of the cosmos contain more ambient gravity than others. We should therefore expect the amount of red shift in light from distant objects to vary according to the amount and the density of gravity fields they penetrate.
« Last Edit: 09/11/2009 20:43:10 by Vern »
 

Offline Mr. Scientist

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Do we need to rethink gravitational red shift?
« Reply #6 on: 09/11/2009 20:42:06 »
It's not conventional, i'll give you that. :)

For instance, we are usually taught spacetime fields permeate everything due to their constant speed of light and also due to the inflationary epoch.
 

Offline Vern

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Do we need to rethink gravitational red shift?
« Reply #7 on: 09/11/2009 21:46:39 »
Yes; I know it is not conventional; I understand the conventional explanation of the effect of gravity. But I'm trying to get to the actual mechanism of the workings of gravity. I couldn't get there within the conventional concepts.

So, if the notion is self consistent, agrees with observations, and I explained it well enough for someone to understand, that's good enough for me. :)

 

Offline Geezer

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Do we need to rethink gravitational red shift?
« Reply #8 on: 10/11/2009 01:37:30 »
Vern,

Does your theory rely on gravitational attraction being consistent throughout all space? I'm wondering if the presence of matter somehow diminishes the effect of gravity. After all, matter does appear to distort space-time, so perhaps it's not too ridiculous to infer that this distortion reduces gravitational "pull" in those volumes of space where there is a relatively large amount of matter.

As there is a lot less matter in intergalactic space, gravity could be much more effective at pulling galaxies together. If this were true, we would not need so much "dark matter" to explain our observations.
 

Offline Vern

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Do we need to rethink gravitational red shift?
« Reply #9 on: 10/11/2009 02:08:19 »
My speculations are far removed from theories which would be much more developed. :) But I do see your point. Gravity should affect gravity in a negative way. When you consider that the equation for the measure of acceleration contains time as an element, and time is affected in a negative way by gravity, then gravitational acceleration must be affected in a negative way by gravity.

I see this as a negative feedback mechanism that would prevent the formation of black holes. It should not be possible to create a black hole by incrementally adding matter. It is the same as saying that you can not get to infinity by incrementally adding finite portions.
 

Offline Geezer

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Do we need to rethink gravitational red shift?
« Reply #10 on: 10/11/2009 03:00:10 »
When you consider that the equation for the measure of acceleration contains time as an element, and time is affected in a negative way by gravity, then gravitational acceleration must be affected in a negative way by gravity.

Um, I confess I didn't even think of time in that context! My view is probably more "Newtonian" than anything else. Our current understanding of gravity is based on our observations in a volume of space that is, relatively speaking, greatly distorted by matter. (If space was not distorted here, our galaxy would fall apart.)

My only thought (speculation as you put it) is that it may not be correct to extrapolate that current understanding of gravity to volumes of space that contain almost no matter. There may be some analogies for this, but I can't seem come up with any at the moment! I do like your negative feedback idea though, probably because my background is mainly in electronics.

We might view this effect (if it exists!) as the dilution of gravity by matter.
« Last Edit: 10/11/2009 03:29:37 by Geezer »
 

Offline Vern

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Do we need to rethink gravitational red shift?
« Reply #11 on: 10/11/2009 03:52:42 »
Quote from: Geezer
We might view this effect (if it exists!) as the dilution of gravity by matter.
Well, we have to view the effect as existent. It is part of the arithmetic that describes nature. Of course it is only theory. But it is part of every theory that we have. The effect is: gravity causes material things within its field to experience time as progressing more slowly. The pull of gravity is experienced as acceleration by material things. Acceleration has time as an element in the equation that describes it. Therefore acceleration must be diminished in a gravity field.

So the thing that causes the acceleration (gravity) must diminish the degree of acceleration. A simple statement would be: gravity affects gravity the way gravity affects light. So gravity must have a damping effect upon gravity. I call that damping effect, negative feedback.
 

Offline Geezer

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Do we need to rethink gravitational red shift?
« Reply #12 on: 10/11/2009 06:31:43 »
Do you think this effect would be sufficient to eliminate the need for much of the proposed "dark matter"?

I suppose another way of looking at it is to believe our observations (without assuming dark matter) and modify our model of gravity accordingly. It would also be necessary to factor in any red shift that was not a function of relative galactic velocities.


 

Offline Vern

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Do we need to rethink gravitational red shift?
« Reply #13 on: 10/11/2009 11:17:03 »
Yes; I suspect you have identified a component that would contribute to galactic rotational anomaly. But there must be other components. Some galaxies that experienced collisions with other galaxies in their recent past (a few million years) seem to have separated from some of their "dark matter". This seems to indicate that so called dark matter is composed mainly of neutral atoms and the "normal" baryonic matter is mostly charged particles, or ions.

This Wiki has a reference to the separation

Quote from: the Wiki link
The most direct observational evidence to date for dark matter is in a system known as the Bullet Cluster. In most regions of the universe, dark matter and visible material are found together,[9] as expected because of their mutual gravitational attraction. In the Bullet Cluster, a collision between two galaxy clusters appears to have caused a separation of dark matter and baryonic matter. X-ray observations show that much of the baryonic matter (in the form of 107–108 Kelvin[10] gas, or plasma) in the system is concentrated in the center of the system. Electromagnetic interactions between passing gas particles caused them to slow down and settle near the point of impact. However, weak gravitational lensing observations of the same system show that much of the mass resides outside of the central region of baryonic gas. Because dark matter does not interact by electromagnetic forces, it would not have been slowed in the same way as the X-ray visible gas, so the dark matter components of the two clusters passed through each other without slowing down substantially. This accounts for the separation. Unlike the galactic rotation curves, this evidence for dark matter is independent of the details of Newtonian gravity, so it is held as direct evidence of the existence of dark matter.[10][11][12]
« Last Edit: 10/11/2009 11:34:44 by Vern »
 

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Do we need to rethink gravitational red shift?
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