Gravitational Lensing : Eddington Experiment

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

  1. The God Valued Senior Member

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    prerequisite : Some knowldege of optics with respect to lense and images formation

    This question came to mind when in one of the recent hot boiled thread, Paddoboy as usual gave some copy paste of Edington Sun Eclipse Experiment of 1919 which contained the Negative Image.....accidentally it opened as full screen image on my browser. The point is lensed image is drawn when we extend/extrapolate the deviated light path. The question is should this extrapolation not be on geodesic only as per GR? Why this extrapolation is straight lined, why not on the natural path which is geodesic ?

    While on the topic there are few further issues..

    1. Are these lensed stars identified (named)?
    2. Why the star image appears to be hyphen only?
    3. What is the conclusive evidence that these hyphens belong to some star image only?

    [Did not get much scientific material on this on the internet, except lot of popscience]
     
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  3. FOLZONI Registered Senior Member

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    My dear Deity
    don't feel fazed by the question. That light paths ARE bent by gravity in space was clear even in Newtonian mechanics. Joachim von Soldner predicted it in 1803 but no one had telescopes good enough then to test it. Soldner extrapolated from the effect of the sun's gravity on successively faster objects, one moving at c following the predicted Newtonian deflection.

    Einstein came up with the identical deflection value in 1913, attaching the relativity nonsense to an otherwise Newtonian prediction. It was about to be tested in August 1914 in a solar eclipse, but, luckily for Einstein, WW1 broke out!

    This gave Einstein the chance to double the predicted deflection before it was tested in 1919!

    Your suspicions about Einstein are correct however but I wish to help you work out the answer for yourself. Of course, as you do, you'll be accused of "megalomania" and "delusions of grandeur" but these are labels to be worn proudly when applied by appropriate persons.

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    FOLZONI

    1. The lensed stars would all be named since any star visible in an eclipse would already be catalogued.
    2. The 'hyphen' is a marker to indicate where the star is.
    3. We can compare the photograph to an untouched nighttime photograph of the same area to see the deflection.
     
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  5. danshawen Valued Senior Member

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    It's not about the curvature (or geometry; ANY geometry).

    Think of it as energy transfer events, and the time dilation that accompanies it. Think both rotational inertia as well as linear, because energy transfer between both modes of propagation is present via the Higgs field and time dilation is different for each. Bound energy is different from unbound energy simply because it is a rotational propagation mode and does not require time in order for the rotational dynamic to work.

    This is the dynamic that makes massive objects spherical and gravitational acceleration to be the only thing that "bends" around them in any geometrical sense.

    Every dimension is light travel time. That light bends in the vicinity of the Sun's rotational inertial mass interacting with the Higgs field in which bound energy exists and light propagates because the Higgs mechanism is the origin and arrow of time itself for both bound and unbound energy.
     
    Last edited: Nov 29, 2015
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  7. origin Trump is the best argument against a democracy. Valued Senior Member

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    On great another thread of pseudoscience starting up in the science section.
     
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  8. danshawen Valued Senior Member

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    Yes, and from the first post. I'll stop, but I doubt it will help. I suffered through a whole course in geometrical optics, optical path lengths, and Cartesian surfaces. Every equation in Kline's book was adulterated or typeset wrong. No wonder Perkin Elmer couldn't get the original Hubble lenses right, which was contemporary with my course.

    Don't wax poetic about geometry around me. I think the idea that G-d loved it is largely misunderstood. He evidently liked going in straight lines really fast or rotating. The rest happened by accident.
     
    Last edited: Nov 29, 2015
  9. The God Valued Senior Member

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    Origin, what is Pseudoscience about the OP?

    The point raised is quite clear, in GR geodesics are path traversed by the light, thats why light in presence of massive object appears bent, the point is we do optics geometry on this and extrapolate the bent line backwards to get the lensed image, why we do this on flat space (straight line)? Extrapolation should also be on the path likely to be travelled by the light at that point not on some imaginary straightline, it should be on geodesic only? You know what is happening, light on this side is following the geodesic (thats as per GR) but extended light is on flat space (non GR).....extend it and attempt to visualise if the source had been Earth would the light have travelled the straight line from the point of deflection onwards in the back direction... IMO no.
     
  10. paddoboy Valued Senior Member

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    Most of what you claim is unevidenced, unsupported, and the PoV of a lay person. Simple as that.
    When you finally surface with reputable links supporting your stuff, it maybe worth looking at.
    Eddington's experiment simply showed that mass curves spacetime, and light travelling in geodesics, follow that curvature. No complication needed, no pseudoscience nonsense needed, just a pure and simple scientific experiment that supported GR and Einstein.
    Every experiment since has also supported it.

    Of course, if you have other ideas, or something that over a 100 years has gone unnoticed, then via the scientific method and peer review, get it out there.
    Rambling about anti GR stuff that you are fond of doing on this forum, has not and will not change anything...
     
  11. The God Valued Senior Member

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    3,546

    You are a very intelligent person, there is no doubt about that. But before I can appreacite what you are attempting to say, please explain what is your objection with the mainstream. You are writing lengthy posts, you have written one in philosophy section, very difficut read, so please briefly explain about your motivation point to push bound / unbound energy, light travel as dimension etc. I am getting a feeling (may be wrong) that origin's Pseudoscince remark is more to do with your post than the OP...
     
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  12. The God Valued Senior Member

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    3,546
    Did you understand the question?
     
  13. paddoboy Valued Senior Member

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    21,529
    Do you understand the advice you have been given?
    You have asked many many questions on this forum, and all with a hidden agenda to somehow discredit science.
    You do not supply any link to support your erroneous claims.
    Plus you are also a lay person.

    In essence as I said, GR has been continually researched, examined and validated with every test that has been raised.
    yet you believe that you have found a problem?

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    No.
     
  14. The God Valued Senior Member

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    So you have not understood the question.
     
  15. The God Valued Senior Member

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    A reference is drawn to a paper..

    http://www.astro.ubc.ca/people/newbury/siam/gravlens.pdf

    At page #2 Fig 2.1, shows the geomtery of lensing. The extrapolated lines are shown from O (observer) to two images S', these extrapolations are on straightline, ideally the extrapolation should be on the geodesics only, because that is the natural path of light.

    Where is the argument that extrapolation can be on a straightline even if light follows the geodesic? The extrapolation from the plane of M (Object) to S' (image) is not a meaningful light path.
     
  16. paddoboy Valued Senior Member

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    21,529
    You have many questions re 20th/21st century cosmology that have been answered to no avail. It's obvious you have an agenda, despite insisting you keep your religion separate from your science. But what your agenda does is force you to misinterpret or not see the correct issue in your vain attempt to invalidate science.
    In any case though, the Eddington experiment simply showed that mass warps/curves spacetime and light follows that curved/warped path called geodesics.
    Sometimes depending on the relative positions of a distant object and an intervening mass, a scenario call gravitational lensing can take place.
    An Einstein cross is an example of this.
    This was not the case with the Eddington experiment.

    Again, whatever problem you imagine, I suggest you get it properly reviewed at the proper sources.
    The following paper may help you.......


    http://arxiv.org/pdf/1010.3829v1.pdf

    Abstract.
    Gravitational lensing has developed into one of the most powerful tools for the analysis of the dark universe. This review summarises the theory of gravitational lensing, its main current applications and representative results achieved so far. It has two parts. In the first, starting from the equation of geodesic deviation, the equations of thin and extended gravitational lensing are derived. In the second, gravitational lensing by stars and planets, galaxies, galaxy clusters and large-scale structures is discussed and summarised.




    . Summary
    Many are the applications of gravitational lensing to cosmology, and the results are numerous, as the preceding discussion has shown. A review like this must be based on a subjective selection which is necessarily biased to some degree. Within these limitations, I summarise the results as follows: • Microlensing experiments in the Galaxy have shown that, although massive compact objects exist in its halo, they are insufficient to make up all the dark matter in the Galactic halo. These studies have extended towards the Andromeda galaxy M 31. It is not clear yet what fraction of the observed microlensing must be attributed to self-lensing by the visible stars. Low-mass planets have been detected by means of microlensing. • Central density profiles of lensing galaxies are well described as isothermal within the radial range where they produce multiple images. Their cores are thus more concentrated than CDM predicts. This indicates that galaxy density profiles have been steepened by baryonic physics. At larger radii, weak galaxy-galaxy lensing shows that the isothermal density profiles steepen and approach the NFW density profile shape. • Galaxy-galaxy lensing finds large halo sizes with radii of & 200 h −1 kpc. Halos of cluster galaxies seem to be smaller, as expected. The biasing of galaxies relative to the darkmatter distribution is found by galaxy-galaxy lensing to be almost scale-independent, or gently increasing with scale. • Galaxies have to be structured in order to explain multiple-image geometries and the high fraction of quadruple compared to double images. Anomalous flux ratios of quadruple images seem to be best explained by lensing, but simulations show that the expected level of substructure is insufficient to explain the observed anomalies. • Measured time delays between multiple images lead to an interesting conflict between the lensing mass distribution and the Hubble constant: Isothermal profiles yield Hubble constants which are substantially too low, and lens models giving compatible Hubble constants have too steep mass profiles. It seems that this conflict can be resolved allowing perturbations of the density profiles. • The statistics of distant sources multiply imaged by galaxies is sensitive to the cosmological parameters. Recent applications of this method showed agreement with a low-density universe with cosmological constant. • Galaxy clusters have to be asymmetric, and they must be dominated by dark matter which is more broadly distributed than the cluster light. Cores in the dark-matter distribution must be small or absent. Frequent and substantial discrepancies between lensing and Xray mass determinations are most likely signalling violent dynamical activity in clusters. • It seems that galaxy clusters in the “concordance”, low-density spatially-flat cosmological models cannot explain the observed abundance of gravitational arcs. Clusters need to be highly substructured and asymmetric, and their dynamics temporarily boosts their strong-lensing efficiency. Yet, theoretical expectations fall substantially below extrapolations of the observed number of arcs. Surprisingly massive and compact clusters which are significant weak and powerful strong lenses exist at redshifts z ' 0.8 and above. • Although cluster density profiles inferred from strong and weak lensing do typically not contradict expectations from CDM, isothermal density profiles are not ruled out by strong gravitational lensing. Claims of flat central profiles are not supported by reasonably asymmetric models. • Typical mass-to-light ratios derived from weak cluster lensing range around ' 200 in solar units, but very high values have occasionally been found. While this may indicate a separation of gas from dark matter in cluster mergers, the possible existence of dark clusters is intriguing. • Cosmic shear, i.e. the distortion of background-galaxy images due to weak gravitational lensing by large-scale structures, has been detected and found to be in remarkable agreement with theoretical expectations. It has enabled constraints on the matter-density parameter and the normalisation parameter σ8 of the dark-matter fluctuations • Systematic effects such as image distortions in the telescope, calibration errors on shape measurements, insufficient knowledge of the non-linear matter power spectrum and the redshift distribution of background galaxies and possible intrinsic alignments of source galaxies are important and substantial and need to be carefully corrected. • Joint analyses of weak lensing and CMB data allow parameter degeneracies in both types of experiment to be lifted. When combined with photometric redshifts of source galaxies, three-dimensional reconstructions of the large-scale matter distribution become possible. This will also allow constraints on the dark energy. • Cosmic magnification, which is more complicated to measure than cosmic shear, can be quantified by the magnification bias. It has been detected, and most recent measurements are also in excellent agreement with theoretical expectations. • Gravitational lensing of the Cosmic Microwave Background is inevitable and affects cosmological parameter estimates obtained from the CMB at the per cent level, if uncorrected. It broadens the peaks in the CMB power spectra, creates small-scale temperature fluctuations in the Silk damping tail and converts part of the E-mode polarisation of the CMB into B modes. CMB lensing has been marginally detected at the expected level by cross-correlating the CMB with distant foreground sources.
     
  17. origin Trump is the best argument against a democracy. Valued Senior Member

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    Each of your questions you ask are clearly answered in the experiment. The questioning is the lead in to more of your pseudoscience.
    What are you talking about? The straight line is where the star appears to be. How can you even give a cursory look at the experiment and not understand that?
     
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  18. danshawen Valued Senior Member

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    We all know from elementary physics that kinematically speaking, energy exists in both translational and rotational forms.

    The old saw thought experiment of Einstein's in which he derived E=mc^2, a photon emitted at one end of a tubular spacecraft and completely absorbed at the other, was possibly the simplest example of how unbound energy can become bound, by being absorbed first by electrons in the absorbing wall.

    An update of the experiment by Wheeler, using mirrors to derive the LORENTZ TRANSFORMATION works after a fashion, but a more important result missed by Wheeler's analysis is that the reflected beam of photons remain bound for any inertial reference frame, so that while the spacecraft doesn't accelerate, the photons emitted and reflected have been given inertia by the bound energy of the electrons in the spacecraft.

    Those electrons are bound energy E=mc^2. The perfect rotation of the energy within them requires no time in order to rotate in every direction at once. Only the HIGGS FIELD may interact with fundamental particles like electrons to exchange energy between rotational and linear propagation modes. In this way, it causes the bending of light mentioned in the OP, and the time dilation associated with it, because the HIGGS FIELD IS THE ORIGIN AND ARROW OF TIME ITSELF. And of gravity too, of course.

    All three dimensions of linear space are light travel time, and calculating space curvature from the most exotic geometry is identical to A WASTE OF TIME, and also exotic math and brainpower.

    All of this idea was developed right here. My IQ is 135 (measured numerous times), on a good day. Alone, I am not capable of sourcing anything like this. Einstein deserves credit. So do Peter Higgs, Englert, Brout, Guralnik, Kibble, Hagen, and thousands of scientists at the LHC, for the discovery of Higgs, which makes it all possible to finally understand. Ancient Greece deserves some credit as well, but not as much as most mathematicians seem to believe.

    Only the Higgs field and bound energy (and to a lesser extent, unbound energy) may impart inertia to bound and unbound energy, from which the field itself also derives inertia locally.

    4 dimensional hybrids of Euclidean space in expressions containing the strong invariant speed of light have nothing at all to do with anything resembling inertia or an aether, time dilation or gravitation, but they have everything to do with miscalculated and erroneous ideas about absolute space and/or time and the curvature of something that is, for the most part, without inertia or especially an origin itself. We exist in a universe composed only of time and energy transfer events which interact via the Higgs field.

    This could have been figured out from only E=mc^2 and a knowledge of the certainty of the existence of the Higss field, if certain theoreticians weren't so heavily invested in Ancient Greek philosophy and dreams of a geometry that doesn't exist other than in an absolute space that for everyone else died in 1905.

    None of this explains charge, people, so get back to work and find out where that comes from. This time, you have a better head start.
     
    Last edited: Dec 1, 2015
  19. PhysBang Valued Senior Member

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    What is a geodesic in the absence of matter? If you can answer this question, then you know the answer to the question above. If you don't know the answer, then stop posting anything at all about GR until you learn.
     
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  20. The God Valued Senior Member

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    Please take two thin lenses, one concave and another convex. Imagine yourself with these two lenses on a Neutron Star surface and conduct simple object image analysis/experiment for each, and post the result here...May be then you will understand the OP. Till then don't bother to respond.
     
  21. The God Valued Senior Member

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    Origin,

    I understand, thats why the question....Its a curved spacetime with distinct curvature, in the context the physical straightline has no meaning simply because even the light cannot traverse this....extrapolation on physical straightline is done, I know, but thats what the point is, that what is the relevance.
     
  22. origin Trump is the best argument against a democracy. Valued Senior Member

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    Clearly you do not understand, as hard as that is to believe...
    The straight line is path that the light from the star appears to be traveling. I know I am just repeating the same thing, but I am at a loss on how to make it any easier to understand.
     
  23. The God Valued Senior Member

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    3,546
    Even I am at loss of word explaining the OP to you....

    We are used to extrapolating in straightline, but in curved spacetime straightline is non existent....

    Why don't you understand, we accept that the light follows the curved path (geodesic), even though a physical straightline can be drawn but light does not follow it.......see what happens to light in BH in presence of highly curved spacetime, will we do our optics in extreme gravity (say on NS surface) on straightlines??

    Come on Origin, trolling shadowsmoke has taken heavy toll on you...
     
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