Gravitational Lensing : Eddington Experiment

paddoboy said:
Thanks for some good links dmoe, ;) but I really doubt it will make any difference to the divine one.
In essence what the crank methodology is, is that if any link refutes their nonsense, then it is derided as 'pop science" an easy way out. ;)
In actual fact my friend, he has also many times dismissed university sites, and if you were up to date with his carryings on, you would have recognised that.
But again, thanks for some nice links. ;)
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paddoboy, I refer you to Post #63 of Thread : http://www.sciforums.com/threads/human-presence-in-arctic.154946/page-4#post-3354215

OK !!??
 
Xelasnave.1947 said:
Dear TG
You said...

The conjoin reading of both the above posts, an attempt to brag about education, false bravado about surprise and reference to 'notes' certainly shows that Xels.1947 copy paste was not as innocent as he is claiming.....anyways i will drop it here, since he has apologised to the forum.

My dear fellow you make assumptions too often that obscure the truth.
Firstly I posted the links because I thought you would find them interesting. Did you read any of them. They all related to GR and so I thought you would find them helpful.

My reference to not making notes and spoiling the ending was my attempt at humour reflecting my cheerful attitude such is the context of my post.

My mistake was my fault I had a friend at my door (we play chess) and I posted in haste but I absolutely reject your suggestion of any evil intent upon my part.

My surprise for you was not an attempt at anything sinister as you propose.

My surprise for you is this..
My education and profession was in law initially and later I owned a real estate office.

My surprise for you was the irony that as a high school student I presented a much better than average aptitude for science (always came first in science at school) and then followed a career in law and real estate.

Now is that not a surprise to you.

Now please tell me how admitting to a background in law on a science forum could be seen in any way at all boastful.

You seem like a nice enough chap but please becareful jumping to conclusions with little knowledge of the situation.. what ever that situation. Dont interpret that as preaching or talking down to you as jumping to hasty conclusions is a mistake many humans make.
There we go a post with no content and not on topic but I felt compeled to present a context that would inform you better.
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He needs a brain transplant. I appreciate links being brought forward in the thread. That shows how real little interest some actually have in what's being discussed. Trying to gain some authority on something as trivial as that.
 
brucep said:
He needs a brain transplant. I appreciate links being brought forward in the thread. That shows how real little interest some actually have in what's being discussed. Trying to gain some authority on something as trivial as that.
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He certainly is not the only one needing a brain transplant! sheesh.....talk about nut balls!
 
dumbest man on earth said:
The God, as you must have surmised by your time on this Forum, very few of the most prolific Posters actually possess any extensive Academic credentials. It seems that many are Pop Science/Internet Educated (if that is an acceptable education!!??) only.
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You mustn't be too hard on the internet dmoe, after all it is where we get all our links from, including your excellent recent links and of course the many reputable links I have given. Sure, there is a heap of crap on the net, just as we get a heap of crap from various agenda driven anti science cranks on this forum. ;)
The problem is of course that its so easy to write off any link as "pop science" when it contradicts your own pseudoscience, as the divine one often does, and that I'm sure you'll recognise.
Mainstream accepted science has been working on GR and its many aspects including gravitational lensing for a 100 years. And we can both bet our short n curlies, that no upstart is going to rewrite it from the comfort and vantage point of a science forum and the associated advantage being unknown.
 
dumbest man on earth said:
The God, it appears to me that your query pertains to whether or not the light path should or would be straight or geodesic(curved)?
Am I correct in that ?
If I am correct then it seems to me that the simplest answer is : The Path of Light is only being Curved or Bent while it is in the area of influence of the distorted or bent geodesic of whatever Mass is causing said Lensing. Once the area of influence is exited, any affected light will then resume a Straight Light Path.

The following Links are to some fairly decent articles/papers that should help you to better understand Gravitational Lensing :
- http://planet.racine.ra.it/testi/Dis/98-14b.htm
- http://www.pa.msu.edu/~abdo/GravitationalLensing.pdf
- http://odessa.phy.sdsmt.edu/~lcorwin/PHYS792DM_Spring2014/PHYS792Spring_DM_W3_1.pdf
- and from the Cornell University Search (Below) - https://ia700408.us.archive.org/11/items/cu31924012311530/cu31924012311530.pdf


I believe that these queries have been addressed, and do not seem to be of prime concern to you.


The God, as you must have surmised by your time on this Forum, very few of the most prolific Posters actually possess any extensive Academic credentials. It seems that many are Pop Science/Internet Educated (if that is an acceptable education!!??) only.
If some Members do not understand a query or cannot supply the answer, they seem to , at times, prefer to find fault with the Member positing the query...instead of simply stating that they do not understand or cannot answer the question.

The God, if you Honestly are truly interested in Learning and fully understanding the areas that this Thread is concerning, than I recommend that you begin by searching the on-line Libraries of any of a multitude of the Major universities.

For instance Cornell University has this Link : https://archive.org/details/cornell , where you can search its Archives.
Simply by typing (without the quotation marks, of course!) " Arthur Eddington " into the search box you can get access to the following .pdf (FOR FREE!!) : https://ia700408.us.archive.org/11/items/cu31924012311530/cu31924012311530.pdf


If you want to actually LEARN more than just regurgitated "pop science"...
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Thanks........Lensing was never in question, it was the conclusion, the hyped conclusion....
 
The God said:
Thanks........Lensing was never in question, it was the conclusion, the hyped conclusion....
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100 years of hyped conclusion?????
Or perhaps an over indulgent, agenda laden, ego inflated god botherer, with no credentials, in his evangelistic mission to try and invalidate GR or any part of 21st century cosmology.
My votes with the second.
 
paddoboy said:
100 years of hyped conclusion?????
Or perhaps an over indulgent, agenda laden, ego inflated god botherer, with no credentials, in his evangelistic mission to try and invalidate GR or any part of 21st century cosmology.
My votes with the second.
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May i remind you post # 848....
 
The God:

I've been vaguely following this thread. I don't understand exactly what your objection to gravitational lensing is, if you actually object to it. So, let me ask you are few direct questions, which you can answer briefly:

Do you believe that gravitational lensing occurs?
Do you believe that the general theory of relativity accurately describes gravitational lensing?
Do you believe that Newtonian gravitation (without GR) can adequately describe gravitatonal lensing?
Do you believe that light travels in "straight lines"?
Do you believe that in GR the closest thing to a "straight line" in a given region of spacetime is a geodesic?
How do you account for the apparent shift in the positions of stars or galaxies when they are lensed by intervening matter (e.g. light from a distant star passing near the Sun)?

Is there something important that you feel that posters in this thread are not appreciating about gravitational lensing? If so, could you please summarise the issue in a paragraph or so?

Thanks.
 
Gravitational Lensing is an observed fact
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 God said:
So, what is the claim ? Do you know or have you understood ?
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I don't believe too many now know what your claim is....the amount of back tracking, the misinterpretation and the general intellectual dishonesty has it lost in a cesspool.
But my post just up there, should unravel all confusion.
 
James R said:
Do you believe that gravitational lensing occurs?
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Yes, I never questioned the image formation.

James R said:
Do you believe that the general theory of relativity accurately describes gravitational lensing?
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No, it does not accurately describe the lensing. The Eddington Experiment in 1919 had huge error bars, many eclipses occurred after 1919 no substantial improvement, with the help of Radio Astronomy the Quasar lensing was observed around Sun / Jupiter and still the error bars were as high as +/- 20% (Ref Schmelzer recent paper ref). Will you call it accurate ? The point is Sun / Jupiter as Lensing objects are hardly few minutes away from us and we come up with a very hugh 20% error bars, what is the sanctity of calculations when lensing objects are millions of light years away ?

James R said:
Do you believe that Newtonian gravitation (without GR) can adequately describe gravitatonal lensing?
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Unfortunately the efforts were abandoned way back in 1919. I can say that Newtonian deflection for massless particle like photon is 2kGM/rc^2 where the value of 'k' could be anywhere between 1 to 2. That explains.


James R said:
Do you believe that light travels in "straight lines"?
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in GR light follows null geodesics, in Newtonian light gets bent....whats your point ?


James R said:
Do you believe that in GR the closest thing to a "straight line" in a given region of spacetime is a geodesic?
Click to expand...

It is not closest. The notion of straightline in GR is geodesic only.


James R said:
How do you account for the apparent shift in the positions of stars or galaxies when they are lensed by intervening matter (e.g. light from a distant star passing near the Sun)?

Is there something important that you feel that posters in this thread are not appreciating about gravitational lensing? If so, could you please summarise the issue in a paragraph or so?

Thanks.
Click to expand...

The point which I am trying to make is that Eddington Experiment does not prove curved spacetime, the way it is pushed. Secondly in curved spacetime, straightlines (Any path having curvature less than null geodesic) has no meaning.
 
The God:

Thanks. That makes things clearer.

The God said:
No, it does not accurately describe the lensing. The Eddington Experiment in 1919 had huge error bars, many eclipses occurred after 1919 no substantial improvement, with the help of Radio Astronomy the Quasar lensing was observed around Sun / Jupiter and still the error bars were as high as +/- 20% (Ref Schmelzer recent paper ref). Will you call it accurate ? The point is Sun / Jupiter as Lensing objects are hardly few minutes away from us and we come up with a very hugh 20% error bars, what is the sanctity of calculations when lensing objects are millions of light years away ?
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In the first sentence you say GR does not accurately describe lensing. But then you go on to talk about experimental data. Which do you think is flawed - the GR theory or the experimental observations, or both? Or are you not sure which is wrong?

Unfortunately the efforts were abandoned way back in 1919. I can say that Newtonian deflection for massless particle like photon is 2kGM/rc^2 where the value of 'k' could be anywhere between 1 to 2. That explains.
Click to expand...
Newtonian theory predicts k=1, doesn't it, and GR predicts k=2?

Do you think that we don't have sufficient experimental data or observations to distinguish between k=1 and k=2?

in GR light follows null geodesics, in Newtonian light gets bent....whats your point ?

It is not closest. The notion of straightline in GR is geodesic only.
Click to expand...
So, "straight line" and "geodesic" are synonymous terms in GR?

The point which I am trying to make is that Eddington Experiment does not prove curved spacetime, the way it is pushed.
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I agree with that. But it doesn't disprove it, either. I would say that it provides positive evidence for curved spacetime.

Do you agree with both of these points?

Secondly in curved spacetime, straightlines (Any path having curvature less than null geodesic) has no meaning.
Click to expand...
I don't think anybody in this thread has talked about a path having curvature less than a null geodesic. Have they?
 
The God said:
No, it does not accurately describe the lensing. The Eddington Experiment in 1919 had huge error bars, many eclipses occurred after 1919 no substantial improvement, with the help of Radio Astronomy the Quasar lensing was observed around Sun / Jupiter and still the error bars were as high as +/- 20% (Ref Schmelzer recent paper ref). Will you call it accurate ? The point is Sun / Jupiter as Lensing objects are hardly few minutes away from us and we come up with a very hugh 20% error bars, what is the sanctity of calculations when lensing objects are millions of light years away ?
Click to expand...
There have been literally hundreds of gravitational lensing scenarios, some already given and linked, which you just dismiss out of hand or refuse to comment. 20%?? Reference?? And again, how about the hundreds of others?,
Here's another anyway.......
http://arxiv.org/pdf/1308.4982v3.pdf
THE THIRD GRAVITATIONAL LENSING ACCURACY TESTING (GREAT3) CHALLENGE HANDBOOK

ABSTRACT:
The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is the third in a series of image analysis challenges, with a goal of testing and facilitating the development of methods for analyzing astronomical images that will be used to measure weak gravitational lensing. This measurement requires extremely precise estimation of very small galaxy shape distortions, in the presence of far larger intrinsic galaxy shapes and distortions due to the blurring kernel caused by the atmosphere, telescope optics, and instrumental effects. The GREAT3 challenge is posed to the astronomy, machine learning, and statistics communities, and includes tests of three specific effects that are of immediate relevance to upcoming weak lensing surveys, two of which have never been tested in a community challenge before. These effects include many novel aspects including realistically complex galaxy models based on high-resolution imaging from space; spatially varying, physically-motivated blurring kernel; and combination of multiple different exposures. To facilitate entry by people new to the field, and for use as a diagnostic tool, the simulation software for the challenge is publicly available, though the exact parameters used for the challenge are blinded. Sample scripts to analyze the challenge data using existing methods will also be provided. See http://great3challenge.info and http: //great3.projects.phys.ucl.ac.uk/leaderboard/ for more information.


Unfortunately the efforts were abandoned way back in 1919. I can say that Newtonian deflection for massless particle like photon is 2kGM/rc^2 where the value of 'k' could be anywhere between 1 to 2. That explains.




in GR light follows null geodesics, in Newtonian light gets bent....whats your point ?




It is not closest. The notion of straightline in GR is geodesic only.




The point which I am trying to make is that Eddington Experiment does not prove curved spacetime, the way it is pushed. Secondly in curved spacetime, straightlines (Any path having curvature less than null geodesic) has no meaning.[/QUOTE]
 
James R said:
In the first sentence you say GR does not accurately describe lensing. But then you go on to talk about experimental data. Which do you think is flawed - the GR theory or the experimental observations, or both? Or are you not sure which is wrong?
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with such state of art equipments, I don't think as on date, we should get error bars of the order of +/- 20%.....This suggests that we are missing something. Don't you think so ?


James R said:
Newtonian theory predicts k=1, doesn't it, and GR predicts k=2?

Do you think that we don't have sufficient experimental data or observations to distinguish between k=1 and k=2?
Click to expand...

True, but what I am saying that we are taking k = 2 and getting huge error bars.


James R said:
So, "straight line" and "geodesic" are synonymous terms in GR?
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Wherever I have used the word straightline in this thread, mostly it was used along with the word Euclidean Straightlines.

James R said:
I agree with that. But it doesn't disprove it, either. I would say that it provides positive evidence for curved spacetime. Do you agree with both of these points?
Click to expand...


Thanks.....But please note that Eddington Experiment was hyped as first proof of GR in 1919. Now if we say that it does disprove GR, then it becomes comical.

James R said:
I don't think anybody in this thread has talked about a path having curvature less than a null geodesic. Have they?
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[/QUOTE]

One particular poster apparently feels that since we can take two points in a curved spacetime and can draw the Euclidean Line as well so such straightlines must exist in curved spacetime, I disagree about the usefulness of such exercise..
 
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