# Gravitational Lensing : Eddington Experiment

Refer to post # 56 then we will continue .
You need to read properly. I'm not disputing or arguing any point on the Sun's corona and any lensing effect, I'm trying to get you to understand that gravitational lensing is caused by any massive object, and need not be a star.
When you understand what I said at post 58 we'll continue.
[Or is this just your usual "white Knight effort to support a fellow pseudo lover]

http://scienceblogs.com/startswithabang/2011/04/20/how-gravitational-lensing-show/

http://www.astro.gla.ac.uk/~martin/outreach/lensing.html

https://en.wikipedia.org/wiki/Einstein_Cross

IMO there is something wrong with you. The diagram under discussion was printed in newspapers around the world so readers could easily understand that this experiment supported GR. You look at the same diagram and somehow think it refutes GR. It is rather sad.

The idea that this in your mind this diagram refutes GR is just mind boggling (and sad).

Origin;

Reference to this fig geometry was made as early as my second post. I am well aware of the prevalent explanation of lensing in GR, but I get a feeling that you are putting in efforts to avoid the point raised by me.

I will try once again..

1. Take two arbitrary points A & B. The least mathematical path between them is an Euclidiean straightline joining them. In case of the flat spacetime this will be the path followed by the light.

2. In case of presence of gravitational field, the spacetime will not be flat and it will be curved, then the path traversed by the light to cover A & B will be curved and it will not be the straightline. That means even the light will have to have a kind of projectile trajectory (as an analogy), but it will not be true projectile as there is no acceleration involved, this being the natural path for light to follow. Straightline between A & B is meaningless here because no object not even light can traverse that.

3. There is nothing preferred. Straightlines or Arc Lines, none have any kind of preference. Then why do we extrapolate in straightlines? Simply because on Earth (in the weak Gravity) the geodesics are straightlines. So our extrapolation is on geodesics only, not that there is something sacrosanct about straightlines.

4. In case of extreme Gravity, arc lines are the geodesics, and the light follows that path, so as a corollary our extension or extrapolation should be on the arc lines (geodesics only), why on straightlines, when they are seemingly meaningless? Thats the point. If you see the geometry of GR lensing picture, then it violates the principle of existence of geodesics and preferentiality, why must it be extended in a straightline to get the image, when around the lensing star we have only curved spacetime?

Lets transport a big Cube (with sharp straight edges) on the surface of the Neutron Star, assuming that Neutron Star has extreme Gravity and appreciable curvature is present, now can you please analyse how an observer will see the cube from a distance?

Origin;

Reference to this fig geometry was made as early as my second post. I am well aware of the prevalent explanation of lensing in GR, but I get a feeling that you are putting in efforts to avoid the point raised by me.
And you believe after more than a 100 years and much validation and research, you have found an anomaly?
If that were the case you would not be here as I have explained many times.
No new theory or invalidation of GR will ever be forthcoming and originating from any science forum or any unqualified lay person.

Lets transport a big Cube (with sharp straight edges) on the surface of the Neutron Star, assuming that Neutron Star has extreme Gravity and appreciable curvature is present, now can you please analyse how an observer will see the cube from a distance?

Firstly no assumption needed with regards to extreme gravity and spacetime curvature around a Neutron star...take it as given, per gravitational collapse and GR.
Secondly any cube on the surface of a Neutron star would be quickly flattened due to the extremes of gravity.

Origin;

Reference to this fig geometry was made as early as my second post. I am well aware of the prevalent explanation of lensing in GR, but I get a feeling that you are putting in efforts to avoid the point raised by me.

I will try once again..

1. Take two arbitrary points A & B. The least mathematical path between them is an Euclidiean straightline joining them. In case of the flat spacetime this will be the path followed by the light.

2. In case of presence of gravitational field, the spacetime will not be flat and it will be curved, then the path traversed by the light to cover A & B will be curved and it will not be the straightline. That means even the light will have to have a kind of projectile trajectory (as an analogy), but it will not be true projectile as there is no acceleration involved, this being the natural path for light to follow. Straightline between A & B is meaningless here because no object not even light can traverse that.

3. There is nothing preferred. Straightlines or Arc Lines, none have any kind of preference. Then why do we extrapolate in straightlines? Simply because on Earth (in the weak Gravity) the geodesics are straightlines. So our extrapolation is on geodesics only, not that there is something sacrosanct about straightlines.
The straight line is showing the apparent position of the star not the actual position of the star. It really isn't difficult.

The path of the light from the emitter to the observer, is dictated by curved spacetime or geodesics.
The eye interprets that curved geodesic path as a straight line and gives an apparent position different from the true position.
The fact that this is so obvious is totally kindergarten stuff and illustrates how religious agendas and other medical problems, can have such an illusory effect on some, in their vain efforts to misinterpret and fabricate non existing problems.

http://content.time.com/time/health/article/0,8599,2104225,00.html

http://www.ncbi.nlm.nih.gov/pubmed/17773357

https://en.wikipedia.org/wiki/Optical_Gravitational_Lensing_Experiment

https://vela.astro.ulg.ac.be/themes/extragal/gravlens/bibdat/engl/DE/didac.html

http://www.einstein-online.info/spotlights/grav_lensing_history

Lets transport a big Cube (with sharp straight edges) on the surface of the Neutron Star, assuming that Neutron Star has extreme Gravity and appreciable curvature is present, now can you please analyse how an observer will see the cube from a distance?

Interesting thought experiment, God. Like Paddo, I would imagine an object so close to the surface of a neutron star would get crushed. However, I get where you're coming from, so I reached out to an expert:

Professor Eric V. Linder said:
Lets transport a big Cube (with sharp straight edges) on the surface of the Neutron Star, assuming that Neutron Star has extreme Gravity and appreciable curvature is present, now can you please analyse how an observer will see the cube from a distance?

Hi Tashja,

The key to thinking about gravitational lensing is the lensing part. The effects really are not that different from looking through normal lenses. You can find many example of videos comparing gravitational lensing images to those seen through lenses like the base of a wine glass on the web. Also see a video glossary by one of my colleagues, Reiko Nakajima, at http://videoglossary.lbl.gov/#n36

Gravity bends light just like a lens does. Why? Because (in almost all situations) gravity acts like an index of refraction. When you look at a fish at the bottom of a pond, you do not see it at its true position because water bends light - it has an index of refraction of 1.33. A straight stick extending from the air into the water will appear bent. The index of refraction of gravity is given by 1+Phi, where Phi is the gravitational potential GM/(r c^2), where M is the mass of a gravitational mass and r is the distance from it. Near the surface of the Sun, the strength of Phi is 0.000001 (10^{-6}), so the index of refraction is quite small and one needs precise experiments to measure the bending of light (i.e. gravitational lensing). For a neutron star, r is much smaller than the Sun, although the mass M is about the same: Phi is about 0.1. So a cube sitting on a neutron star would appear about the same as a cube sitting at the bottom of a pool, with regard to lensing effects!

Only when you get to black holes, where Phi is near 1, do new aspects of gravitational lensing enter. This is because interpreting gravity as an index of refraction is only good when Phi is much less than 1, what is called the linear gravitation theory.

Thanks for your interest in gravity.

Best,
Eric

Interesting thought experiment, God. Like Paddo, I would imagine an object so close to the surface of a neutron star would get crushed. However, I get where you're coming from, so I reached out to an expert:

Thanks, Tashja.....You are extremely resourceful.

The professor has explained the lensing. I have no dispute with the lensing aspect, it is well observed and the Geometry shown is perfect. The point raised by me is different; Does this 'valid explanation' confirm curved spacetime or Gravitational Newtonian kind of deflection with the flat spacetime in background? I am of the opinion it confirms Newtonian (barring the error of half in Newtonian, thats the different issue) with the flat spacetime as background.

My argument is..

1. The image will not form if the light is not deviated from the natural path.
2. There is no preference for the straightline over the arc lines
3. Extrapolation / Extension of lights (in ray Diagrams) can only be made on the path of light, not on any arbitrary straight or curved lines.

Having said that, it is clear that in case of curved spacetime around a massive object, the natural path of of the light is geodesic only, so as per Sr#1 it is not a deviation, its THE natural path for light, and no image shall form if curved spacetime is a reality. But if we take flat spacetime and consider Newtonian deflection of light, then it is the deviation from the natural path of light and image shall form. To prove this was the purpose of NS thought experiment.

The God said:
You may also like to consider a situation wherein source and observer are both at the surface of a Neutron Star (Extreme Gravity and curved spacetime), as we increase the distance between the observer and the source, the observer sees the object slowly lifting up in the air (towards sky) due to this straightline extrapolation. My argument is that you can only make the extrapolation on the path of light, a straightline is not the path of light in the curved spacetime.

Professor has confirmed that even on the surface of Neutron Star, we will see images, surely, we will, but that is only possible if background is flat spacetime. Again if the curved spacetime were to be the reality on the surface of NS then we may see a distorted object, but certainly not an image at some other place. In Newtonian we will see the image lifted as if object is lying inside water as explained by kind Professor.

PS: Paddo and you are right, the cube may be crushed, but then the purpose was to understand the optics in extreme curved spacetime not the crushing power of Gravity. I could not have invoked BH because then light path is simply one way inside EH.

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Interesting thought experiment, God. Like Paddo, I would imagine an object so close to the surface of a neutron star would get crushed. However, I get where you're coming from, so I reached out to an expert:
Nice post by Prof. Linder. The following is a derivation by Kevin Brown he calls refraction on relativity. Pretty nice. Notice that dphi=4M/r_o + 6pi-8(M/r)^2 + ........ Is equivalent to the GR weak field prediction dphi=4M/r in the first order. This is the prediction Professor Eddington carried to the first empirical test of GR. So the path of the light can be modeled using the refraction index. The way it's described, derived, from GR is the path of the light, null geodesic, follows the local spacetime curvature. The local path spacetime curvature in an infinitesimal, real small, but when it's accounted for by remote coordinates, observed from the HST, over the lights entire path the spacetime curvature near massive objects will be measured to be lensed. The term used.
In the later pages of this Chapter 2 from Taylor and Wheeler Exploring Black Holes there's a discussion about the remote Schwarzschild bookkeeper coordinates. Actually page 2-34
http://www.mathpages.com/rr/s8-04/8-04.htm
Choose Chapter 2 Curving
Paddoboy linked a derivation of the Einstein Ring lensed equation but the way it's written just confused me. My problem.
r_src=the physical position of the source of the light being lensed. r being the distance between the source and the observer which is r_obs.

Einstein ring angle = [4Mr_src/r_obs(r_obs + r_src) ]^1/2

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The original point still remains unanswered..

"In case of curved spacetime around a massive object, the natural path of of the light is geodesic only, so as per Fermat's principle it is not a deviation, its THE natural path for light, and no image shall form if curved spacetime is a reality. But if we take flat spacetime and consider Newtonian deflection of light, then it is the deviation from the natural path of light and image shall form."

The Newtonian flat spacetime gives a deviation of 2M/r while the GR maths yields 4M/r, although GR calculations offer the correct angle, but that is the curvature of spacetime not the deviation. This suggests that we need to work out correction / improvization / New theory which is under flat spacetime as background.

I know this is not going to happen with such objection in a forum like this, when great mainstream guys assent to ridiculous possibilities of meeting their now long dead great great grand fathers and also meeting their not yet born great great grand children. It calls for a complete paradigm shift and tremendous courage to re assess the GR predictions, scientists community will not be able to do it. Some public activist has to come forward and question the impossibility of time travel (meeting great great grand pa and great great grand kid) and move to the government and higher judiciary in the public interest for wastage of huge amounts of tax payers money in nonsensical research on these lines. I am sure scientists are accountable to public at large when they are funded by Public Money.

The curved spacetime / Flat space background can simply be established by following observations also...

1. Analogous experiment when an object is directly viewed in the curved spacetime, if there is no image its curved spacetime if there is image it is flat spacetime......'Fisheye Lense' gives an idea that there will not be image if it is curved spacetime. Like already discussed, on the Neutron Star surface an object will be visible as image lifted up in the sky in case of Flat Spacetime as background, but will be distorted (like seen from a fish eyelense) object view in case of curved spacetime.

2. Around any massive object (Lensing Galaxy etc) there will be an envelop of bigger ring (may be ellipticall depending on the orientation and shape of galaxy), beyond this point light deviation will be almost nil due to Gravity of this massive Galaxy. The observation and analysis of observed objects inside this ring with respect to how many are real and how many are images will conclusively establish whether we have curved spacetime or flat space.

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Interesting thought experiment, God. Like Paddo, I would imagine an object so close to the surface of a neutron star would get crushed. However, I get where you're coming from, so I reached out to an expert:

Thanks for your usual good work tashja and pass our thanks onto the Professor for confirming what most of us did know.
In essence, no problem exists and GR stands as firm as it always has.

The original point still remains unanswered..
There is no original point and never was....It's no more then a phony fabrication to supposedly add credibility to your past unsupported claims, the latest of which has been shifted to pseudoscience....I would have actually gone one rung lower.
"In case of curved spacetime around a massive object, the natural path of of the light is geodesic only, so as per Fermat's principle it is not a deviation, its THE natural path for light, and no image shall form if curved spacetime is a reality. But if we take flat spacetime and consider Newtonian deflection of light, then it is the deviation from the natural path of light and image shall form.".
The Newtonian flat spacetime gives a deviation of 2M/r while the GR maths yields 4M/r, although GR calculations offer the correct angle, but that is the curvature of spacetime not the deviation. This suggests that we need to work out correction / improvization / New theory which is under flat spacetime as background.
More pseudoscientific claims
I know this is not going to happen with such objection in a forum like this, when great mainstream guys assent to ridiculous possibilities of meeting their now long dead great great grand fathers and also meeting their not yet born great great grand children. It calls for a complete paradigm shift and tremendous courage to re assess the GR predictions, scientists community will not be able to do it.
Any modification. extension of GR is not going to happen on a science forum.
You have been told this before, and I'll keep on telling you as long as you continue to post such outrageous claims and fabricated scenarios.

Some public activist has to come forward and question the impossibility of time travel (meeting great great grand pa and great great grand kid) and move to the government and higher judiciary in the public interest for wastage of huge amounts of tax payers money in nonsensical research on these lines. I am sure scientists are accountable to public at large when they are funded by Public Money.
While most normal folk on this forum do realize that time travel is not forbidden by GR, they are also smart enough to recognise another egotistical god driven rant as is yours above.
The curved spacetime / Flat space background can simply be established by following observations also...
Spacetime tells matter how to move; matter tells spacetime how to curve.
John Wheeler:

https://einstein.stanford.edu/

I don't know. You are the kind of person to be almost completely ignorant yet to also prance around with extreme arrogance.

You have demonstrated you don't understand this topic, yet you insult everyone who tries to help you.

So being rude to you may be the correct response.

On the other hand, you have a mental deficiency, perhaps even to the point that you have an illness that should see treatment. I don't want you to suffer, even if your illness makes you lash out at others.

And as per other cranks like jcc and chinglu, constant theorist, the religious agenda is just as strong in this one.

And as per other cranks like jcc and chinglu, constant theorist, the religious agenda is just as strong in this one.

To see science one needs to be educated...for linking anything with religion no knowledge/science is required. It is well established that you are an illiterate, so you will see religion or agenda everywhere.

Now please stay away and do not crap on this thread, this is not for illiterates...

To see science one needs to be educated...for linking anything with religion no knowledge/science is required. It is well established that you are an illiterate, so you will see religion or agenda everywhere.

Now please stay away and do not crap on this thread, this is not for illiterates...
Illiterate?
And I'm certainly smart enough to have revealed two agendas re yourself now....the religious one and rajesh of course.
Take it easy though, I know the truth hurts.

Illiterate?
And I'm certainly smart enough to have revealed two agendas re yourself now....the religious one and rajesh of course.
Take it easy though, I know the truth hurts.

Stop playing your games, will you..

Stop playing your games, will you..

I don't play games my friend. I'm just totally adverse to god botherers, those with delusions of grandeur, anti mainstream science nuts, or any combination thereof, that pretend to find fault with accepted mainstream science and/or GR.
And I will most certainly remind these "would be's if they could be's", the reasons why they are wrong, and the logical extension that if any of them had anything of substance, [including yourself] you would not really be here.

The path of the light from the emitter to the observer, is dictated by curved spacetime or geodesics.
The eye interprets that curved geodesic path as a straight line and gives an apparent position different from the true position.

I don't play games my friend. I'm just totally adverse to god botherers, those with delusions of grandeur, anti mainstream science nuts, or any combination thereof, that pretend to find fault with accepted mainstream science and/or GR.
And I will most certainly remind these "would be's if they could be's", the reasons why they are wrong, and the logical extension that if any of them had anything of substance, [including yourself] you would not really be here.

The path of the light from the emitter to the observer, is dictated by curved spacetime or geodesics.
The eye interprets that curved geodesic path as a straight line and gives an apparent position different from the true position.

You have not understood, I am not disputing this geometry or this explanation. This is correct. But this interpretation holds only in flat space not in curved spacetime. The curved geodesic path from source to our eye is the natural path of light if theory of curved spacetime is correct, in this case there shall not be any image or extension to apparent image. But in case of flat space and deviation due to Newtonian the light from source gets defelected and the path of light is not the natural path of light and image gets formed. Am I being religious in making this claim? Why don't you respond on this...

You have not understood, I am not disputing this geometry or this explanation. This is correct. But this interpretation holds only in flat space not in curved spacetime. The curved geodesic path from source to our eye is the natural path of light if theory of curved spacetime is correct, in this case there shall not be any image or extension to apparent image. But in case of flat space and deviation due to Newtonian the light from source gets defelected and the path of light is not the natural path of light and image gets formed. Am I being religious in making this claim? Why don't you respond on this...
Bullshit.
You can pretend to your hearts content, but it hasn't fooled anyone.
Religious agendas are used all the time, along with the general delusions of grandeur that goes with it, by cranks to try and invalidate science.
In answer to your question, "Am I being religious in making this claim"? yes.
The path of the light from the emitter to the observer, is dictated by curved spacetime or geodesics.
The eye interprets that curved geodesic path as a straight line and gives an apparent position different from the true position.

The problem you envisage is non existent.

The curved geodesic path from source to our eye is the natural path of light if theory of curved spacetime is correct,
The theory has been shown to be correct despite your continuing doubts.
in this case there shall not be any image or extension to apparent image.
Bullshit and really to silly to even comment on.

The theory has been shown to be correct despite your continuing doubts.

Bullshit and really to silly to even comment on.

But this is THE science......Image shall form only if there is any deviation from the natural path of light and the natural path is defined by Fermat's Principle......In curved spacetime, the curved path is the natural path, so it cannot be treated as deviation and no image shall form. But image is forming, that means it is not the curved spacetime but deflection of light due to Gravity in flat space background..So simple.

In curved spacetime, Euclidean straightline is meaningless, because nothing can traverse that, not even light. [except possibly the radial lines.]. Resorting to flat Newtonian Space (or Minkowski Spacetime) to provide linear extrapolation is bad. This is not even approximation.