Gravitational Lensing : Eddington Experiment

Discussion in 'Astronomy, Exobiology, & Cosmology' started by The God, Nov 29, 2015.

  1. The God Valued Senior Member

    Messages:
    3,546
    Relax Paddoboy, learn to relax. Try focussing on content also; you have shown tremendous learning at 70..
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. paddoboy Valued Senior Member

    Messages:
    21,647
    I'm there, you have to get there.

    Please Register or Log in to view the hidden image!

    Best of luck with that endeavour.
    But back on subject which once again you so cleverly avoid.
    You've been given two answers to your previous primary grade question, if you see the need to refute either, all you need to do is show some reference supporting whatever alternative stance you are taking.
    Oh, and of course I don't suppose its any need asking for your credentials: Obviously you have none and are talking through your hat as usual.
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. Schmelzer Valued Senior Member

    Messages:
    3,703
    No. What is called the Newtonian approximation in GR, that means, the metric defined by \( ds^2 = (1+\Phi) dt^2 - (1-\Phi)(dx^2+dy^2 +dz^2)\) (modulo constants) with the Newtonian potential is, nonetheless, not Newtonian theory but different. In particular, particles will follow geodesics of that metric, clocks will time-dilated and rulers contracted as in relativity, and the metric is, by the way, even curved.
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. The God Valued Senior Member

    Messages:
    3,546
    Ok, thanks. My reference was Newtonian Force concept as Gravity, which certainly is conceptually different from GR.
     
  8. PhysBang Valued Senior Member

    Messages:
    2,422
  9. The God Valued Senior Member

    Messages:
    3,546
    Don't fool around. This is not 'Altered Newtonian Gravity'....Don't try to push GR approximations and weak field manipulations as Altered Newtonian. Learn something about MOND, then you will realise what is altered or modified Newtonian could mean. https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics

    You are spewing too much venom and abuses here and there, almost everywhere, you are fumbling too much, that one lie that you are a PHD has taken a heavy toll on you. By the way what was the specialization of your PhD (or was it PHD in abuses and expletives).
     
  10. James R Just this guy, you know? Staff Member

    Messages:
    30,644
    The God:

    Did PhysBang claim to have a PhD?
    Do you have evidence that he does not have one?

    Please contact me by private messaging to provide me with the details of this lie you allege. We have a site policy against knowingly telling lies, and if you wish I will enforce it in this case to officially warn either you or PhysBang - whoever is lying about this.

    Is this acceptable to you? Or do you want to retract your accusation of lying?
     
  11. The God Valued Senior Member

    Messages:
    3,546
    I will surely, but why don't you look at the way...Physbang is calling me liar in unrelated threads and posts, he is calling danshaven as liar and as 'danthecrank', he is calling farsight as liar and asshole without provocation.
     
  12. The God Valued Senior Member

    Messages:
    3,546
    Post # 909
    1. A PhD educated guy will never write PHD for PhD. [even keyboard accepts PhD, so it is not auto correction either]
    2. Subsequent post of his, he claims to have forgotten about jovian experiments.
    3. The open and too much abuses does not reflect his being PhD.
    4. His posts are full of inaccuracies, he calls altered newtonian, which is not, he calls approximations as inaccurate physics, which is not, he is still disputing that lensing angle values were available to Eddington even before he conducted his experiment in 1919.
    5. His posts do not reflect PhD in any topic of cosmology, pl refer to Schmelzer posts, you get the difference.

    he is claiming to have a PhD, I asked him in which specific aspect, he is silent. These create a doubt about the veracity of his claim that he is a PhD.
     
  13. PhysBang Valued Senior Member

    Messages:
    2,422
    If I was held to an academic standard that reflects "The God"'s scholarship, I would gladly refuse a PhD or a PHD.

    And I am sorry that "The God" claimed that I had said something about his diagram (I'm not sure which one), when I had not.
     
    Last edited: Jan 26, 2016
  14. paddoboy Valued Senior Member

    Messages:
    21,647
    I'm sure that most on this forum do know how you can manipulate, misinterpret, and indulge constantly in outright intellectual dishonesty, as well as ridiculously pedant nonsense.
    I'm sure that most on this forum also realise that all you have ever claimed, in opposition to mainstream cosmology, has been totally and thoroughly invalidated by many professional people, both on and off this forum.
    I'm also just as sure that PhysBang has more honesty, intelligence and decency in his little finger than you could ever have in your whole being.
    I'm sure that all on this forum, realise that you are an uninformed amateurish lay person, troubled somewhat with delusions of grandeur about your own importance and imaginary credentials which you are unable to reveal simply because they do not exists.
    And finally, it is also a fact, that Schmelzer, despite being a Maverick scientists of sorts, has also refuted most all the nonsense that you preach and expect people to believe.
     
    Last edited: Jan 26, 2016
  15. paddoboy Valued Senior Member

    Messages:
    21,647
    Pot, Kettle, Black????????
     
  16. Xelasnave.1947 Valued Senior Member

    Messages:
    3,312
    Dear tg I think James R mentioned messaging.
     
  17. hansda Valued Senior Member

    Messages:
    2,219
    Schmelzer:

    I think you are not able to answer my above question.
     
  18. hansda Valued Senior Member

    Messages:
    2,219
    In the "weak field approximation", which one you will prefer Newtonian Model or GR ?
     
  19. PhysBang Valued Senior Member

    Messages:
    2,422
    In the weak field approximation, GR is Newtonian Mechanics.

    Newtonian Mechanics is amazingly accurate. So it is foolish not to use it where appropriate and if one's theory of gravity disagrees with the workings of Newtonian Mechanics except in the particular cases where Newtonian Mechanics goes wrong, then one's theory of gravity is wrong.

    The thing about GR is that it can predict exactly the same things as Newtonian Mechanics, except where it predicts something different, it gets the answer right and Newtonian Mechanics gets it wrong. Gravitational lensing is one example. The orbit of Mercury is another example.

    Sometimes, we can even use Newtonian Mechanics when there are non-negligible relativistic effects by adding one or two corrective terms. But we know which terms to add in because we can figure that out by carefully considering GR.
     
  20. hansda Valued Senior Member

    Messages:
    2,219
    In Newtonian Mechanics, it is flat spacetime or there is no "curvature of spacetime". So in the "weak field approximation of GR" also, there is no "curvature of spacetime".
     
    Last edited: Jan 26, 2016
  21. PhysBang Valued Senior Member

    Messages:
    2,422
    There isn't in the calculations.

    Nobody who uses the weak field approximation thinks that they are using something that faithfully represents the metaphysics of the world, however.
     
  22. The God Valued Senior Member

    Messages:
    3,546
    • Please do no tell deliberate lies and misrepresent the postings of other members.
    I appreciate the way you have built this up....

    1.
    First and foremost what is weak field approximation ? this question was asked to Physbang, he avoided...so let me try. The criterion is actually R(s)/R for an object, where R(s) is the schwarzschild radius and R is the radius of the object. For the earth Rs is equal to around 10 mm, so you can see that 10 mm / 6400 km is a very small figure, similarly Rs is around 3 Kms for sun, there also Rs / R will come out to be very small. This becomes appreciable only when we talk of Neutron Star or near BH singularity.

    2. Secondly, please note, the GR never gets converted or approximated as Newtonian Universal Gravity theory, because the fundamental basis of both these theories are different. In GR (weak field or strong field) there is no concept of force.Period. What is common is that in weak field the motion of a particle as described by Classical Newtonian Gravity is same as that of what comes out with GR approximations.

    3. There is practically no meaning of the term flat spacetime in GR. Yes this concept is there, but it is associated with terms like infinitesimal dx or asymptotic etc...like it tantamounts to saying that there is no gravity.

    4. This one is tricky, around an object, the path taken by light has a very small deflection, similarly the path taken by an object with some mass m travelling at a lesser speed than c, has a bigger deflection. That means solution is dependent on the initial conditions. So how do you define Gravity in GR ? There is no such compulsions of initial conditions in Newtonian Universal Gravity, simply because forces are superimposable, vectorially.

    5. We generally work on Schwarzschild solution, that too is approximate, non spinning which is not the reality, no movement of heavy object, again no reality, the smaller object is considered as particle (negligible as compared to heavy object) which again is not a reality. Basically it is damn difficult to solve even a 2-body problem in GR without approximations here and there.
     
    Last edited: Jan 27, 2016
  23. The God Valued Senior Member

    Messages:
    3,546
    But you will refuse only if someone is willing to confer......none.
     

Share This Page