Some questions for better understanding of Main Stream Cosmology

Discussion in 'Astronomy, Exobiology, & Cosmology' started by RajeshTrivedi, Aug 28, 2014.

  1. RajeshTrivedi Valued Senior Member

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    But where are the answers ?? Whatever you and origin have stated is no answer.

    Mr Paddoboy, let me tell you, and its a fact, that you have not understood what is space-time 4-D depiction. It is pure mathematics, which again is kind of beyond yours (and mine too..) scope of understanding. If you had understood even the qualitative aspect of the spacetime then also you would have been able to answer these questions. But alas, you are still bluffing around. I am again typing question for you in simple language, see if you still find them silly or answered.

    Q1. Space time curvature should be a closed curve, simply because there is no specific orientation for the object in the space ?

    (Take the 2-D geometry given in your gsfc link away, and try to conceptualize the real 4-D, then you will yourself ask the same question that how the light could exit from the curvature.)

    Q2. For light Geodesic is kind of straightline and light is not called as bent, it is just following the path of Geodesic at constant speed. Then how can you extrapolate away from Geodesic ?? The red dashed line may be the POV for Earth as observer, but light is expected to take the path of curvature only. As I said, reverse the source and observer, then light will not travel your POW path.




    See for yourself, which post of yours or origin have answered these questions.
     
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  3. paddoboy Valued Senior Member

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    Your questions at first made no sense, they were gobblyddook, scientific sounding words misplaced, unscientific terminology.
    When your confusion became slightly clearer, they were answered.
    Whether you accept them or not is no skin off my nose. They are accepted mainstream answers.
    But of course, instead of whinging about origin and I not answering your questions, why dont you do as I suugest?
    It's that simple. Or are you not interested in ANY MAINSTREAM ANSWER?

    Bye Rajesh, obviously you are travelling in ever decreasing circles.
    Hope you find whatever answer you are comfortable with.
     
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  5. RajeshTrivedi Valued Senior Member

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    Question is pretty simple, For your easier understanding, I used the simple words.


    No, 3rd obvious conclusion is this lensing as explained as on date calls for a re-look.


    Yes true, but how many on this forum, can conclusively say that they have understood this spacetime distortion Vs Gravity.
     
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  7. origin Trump is the best argument against a democracy. Valued Senior Member

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    Your question makes no sense that is the problem, not the size of the words. This concept is really not that difficult. My guess is that you have not looked at the links. If you looked at the link that I provided explaining gravitational lensing and you still don't get it then I am afraid you have bigger problems than I thought.

    Ignorance and arrogance is a terrible combination



    I think just about everyone in the forum understands lensing and space distortion on a fundamental level.
     
  8. RajeshTrivedi Valued Senior Member

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    Origin, Let us leave aside the bitterness and focus on the issue.

    The link which you have put up is the same as that was put up by Paddoboy in earlier post, and reference of dashed red line is taken from that link only.

    You would agree that extrapolated images in optics are made, on the extended path of light only. Now please refer to the first picture on your link...

    The path of the light around Massive Galaxy, is of curvature only as shown in exaggeration in picture.... Then how can we extrapolate on the dashed Red Line ?? That's Q2.

    Q1 is simpler, Again please refer to picture 1 only. It appears that light exit point towards Earth is the intersection point of Red and Blue line as shown. What is the significance of this Exit Point, why we are showing only the planar curvature, the curvature has to be a kind of envelop around the Galaxy. So how the light gets out of this closed curvature at that very point.

    You agree or not but this simple depiction of space time curvature in 2-D is quite misleading, it gives the predicted result, I do not dispute that, but leaves many unanswered questions. Two of them are in front of us.
     
  9. origin Trump is the best argument against a democracy. Valued Senior Member

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    The dotted line is only showing where it looks like the object is, not where it actually is. It is that simple. Here is an example, lets assume that there is someone standing behind a house and there is a mirror angled on the side of the house so that when you are standing in front of the house see the persons reflection. You can point at that reflection and say there is the person but actually they are not there, they are behind the house. OK, not hard to understand, is it?

    Really? Why would the light get trapped? Let's use another example. If we launch a space probe that flys by the moon the probes trajectory will be changed by the moons gravity, in the same way light will be. The probe will not be trapped into an orbit unless the speed of the probe is slow enough and the probe is the right distance from the surface of the moon.

    Light will be slightly deflected by the gravity around a mass, which is analogous to a space probe path being deflected around a mass.

    The 2-D depiction is not misleading it simply has limitations inherent in any analogy. The questions you have asked arise from your lack of knowledge of the theory not from a problem with the theory.

    I once again encourage you to take a course on this to learn the theories, unless this is just trolling in which case you can carry on as you have been.:shrug:
     
  10. OnlyMe Valued Senior Member

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    Why in the case being discussed would you believe this to be the case? Only within the theoretical context of a light path near, at or within the event horizon of a black hole, would that seem to be a reasonable argument. Here you are talking about the gravity well of a galaxy... And insufficient spacetime curvature to even approach a closed path!

    I am not really sure I fully understand what you are getting at... But if what you mean is that an observer at the quasar would not see light from the earth following the same path to the quasar, as the light from the quasar travels to reach the earth, that is a reasonable assumption.

    But then, was the earth even around long enough in the past, for any light from the earth to reach that observeR at the quasar?.. Not according to what we understand about when that light left the quasar and how old our solar system is. No observer at the quasar could even know we exist yet, even if the quasar still exists.

    And yes the dashed lines only depict where we would expect the light to have originated, were there no gravitational lending.

    I have not been following this discussion in any detail and have no real interest in, or time to go back and try to dig any sense out of past posts, so can you tell me just what your objection or point is.., in a few words?
     
  11. forrest noble Registered Senior Member

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    Realize the topic here -- which is related to better understanding the mainstream model. This does not mean that the mainstream explanation is correct, the final answer, or that there are not better answers out there, mainstream or not.
     
  12. Aqueous Id flat Earth skeptic Valued Senior Member

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    What mainstream model?

    Name one.

    What mainstream answers are better than other mainstream answer?

    :shrug:l
     
  13. paddoboy Valued Senior Member

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    Well at least we are now seeing the reality of an agenda behind the questions asked, and the subsequent refusal to accept an answer. The ways of pseudo quackery and conspiracy adherents.



    Other then for yourself, it isn't really that hard to understand and accept.
    Firstly gravity is exhibited when spacetime distortions take place in the presence of mass. There is no such thing as "spacetime distortion V's Gravity"
    Light then follows geodesic paths.
    In regards to all the inane agenda laden questions you have asked, the standard BB cosmology model and GR stands firm.




    The mainstream model is the mainstream model, because it has undergone peer review, and according to all observational and experimental evidence, aligns with reality closer then any other model.
    In other words it has already run the gauntlet and passed, while most alternative models [at least those presented so far on this forum] have fallen to the wayside.
    It's as simple as that.
     
  14. RajeshTrivedi Valued Senior Member

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    There is no agenda, these are just the questions, we need to get them resolved.

    There are few more related questions...

    Q3. This question is about significance and physical meaning of resultant distortion in space time curvature of a multi-object system. What is the significance and meaning of spacetime distortion by a Galaxy ?? Why this question ?? Because it is observed / demonstrated that an entire Galaxy causes space time curvature and light lenses due to this. Individual object causing distortion is understandable but..... Please note that Eddington observation was based on Sun lensing, while the lensing (as shown in the link) is by a Galaxy. How ??

    Q4. It is a vast universe, billions of Galaxies and billions of massive objects are present. A very high probability that we will always (every moment of observation) get a back ground star (light source), a massive object and of course Earth (observer) aligned. So we should see lenses very often, kind of many significant lenses every night. Do we ?

    Q5. Is it not likely that a remote-light observed by us, is multi lensed ? Take for example Paddoboy provided link, it shows Quasar light getting lensed by a massive Galaxy, there certainly would be multiple stars after the light leaves the curvature, so how can we be sure that this light is lensed only once ? Won't there be a big mess of poor light stranded here and there ??


    Lensed here means light getting into the path of curvature created by many objects in its journey towards Earth...
     
    Last edited: Sep 25, 2014
  15. origin Trump is the best argument against a democracy. Valued Senior Member

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    The meaning is that a galaxies gravity can distort space. The significance is also that the galaxies gravity distorts space, I guess. What do you thing the significance is?

    Galaxies have a gravitational field, that is how.

    Really do you have some evidence for this?

    I disagree that 'significant' lensing is common or should be common.

    In most cases the effect of gravity on distant objects is not that significant.
     
  16. paddoboy Valued Senior Member

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    21,647
    Who are the "we" you refer to that needs to get these questions resolved?
    Sure, there are a few unanswered questions with mainstream cosmology, but certainly not any along the lines that you have asked.
    Or are you suggesting a conspiracy by mainstream cosmologists in trying to keep stuff quite that would invalidate it?
    How do you think present mainstream cosmology achieved its present status.
    The BB for instance, way back in the fifties was just one of three hypothesis that cosmologists thought could be applicable to the origin of the Universe. The other two were "Steady State"and "Oscillating"....Why and how do you think the BB gained ascendancy over the other two?
    Maybe you need to go back at the very foundations of science, and the scientific methodology and peer review.
    Why would you not believe that a massive galaxy does not warp/curve spacetime?
    Because that's what you appear to be suggesting.
    And finally, the original questions you posed have all been answered, as much as you want to deny that fact.
     
  17. paddoboy Valued Senior Member

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    21,647


    I have just gone through the first 20 or 30 posts, and really, every question was answered, although some rather weird misinterpretations and misunderstandings of those answers by the questioner was astounding to say the least.
    Some advice from two of our best above should really be heeded, although, in my opinion, the obvious agenda harbored by Rajish, will be near impossible to overcome.

    The agenda?? I surmise a religious or Creationist agenda, as generally they seem to misinterpret, misunderstand, or just plain ignore, in a similar fashion that the answers to these questions have been.
    Yet, even the Catholic church had to finally admit to the mountains of evidence supporting the BB model of Universe/spacetime evolution.
     
  18. FOLZONI Registered Senior Member

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    Once again, creation & evolution are mixed up together willy-nilly in the post below.
    Luckily however the problem is easily solved as the highlighted parts of the quote reveal. Whether 6,000 year Bible creationism or 13,700,000,000 year BB creationism we have a difference only of degree NOT of kind. This is why the Catholic church (and most other monotheisms) so readily accepts the BB & Einsteinian spacetime!

    FOLZONI
     
  19. paddoboy Valued Senior Member

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    No similarity whatsoever. We all know what the Catholic church mean by creationism, obviously.
    They support the BB for two reasons.
    [1]The overwhelming evidence supporting the model:
    [2] And simply because it says nothing about the how and why of the BB, and in fact is outside the parameters of the BB theory itself, and so they then chose to invoke there magic pixie in the sky, without any further scientific observations or gathering of data, as the cause.

    With the BB/Inflationary model, although beginning at t+10-43 seconds, the inference according to the model, is that space and time [spacetime] [as we know them] evolved by expansion.
    From that point extrapolating backwards, there have been a number of speculative explanations, including from nothing, and the Universe being the ultimate free lunch.

    Quite a difference.
     
  20. RajeshTrivedi Valued Senior Member

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    Gravity is a distortion of spacetime.....

    You are suggesting that effect brought the cause... Since it was your guess only, so not much harm done.

    The Galaxy Gravity does not cause distortion of space, it is the distortion of space which causes Gravity.

    Hope now you have understood, when I asked about significance and meaning of spacetime distortion by multiple objects of a Galaxy.

    The question is meaningless if we are simply talking about Newtonian Concept of Gravity as a force but Einstein didn't think gravity was a force, he proposed gravity as a distortion of space-time.
     
  21. RajeshTrivedi Valued Senior Member

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    Paddoboy,

    1. Religion is the last thing in my mind when I am on this sub forum.

    2. I have understood that there are certain open questions about initial phase of BB etc, so I have reconciled with that and no more arguments on that.

    3. Gravitational Lensing is a clear established theory as on date, with no ifs and buts or no singularity or no open handles. It does not mean that it is not open to questions. So the escape here is not that these questions are open and known to everyone, and we are working on it and may be QGT will answer.

    I have no astro-physicist as my friend, so I seek the answers from this forum and WE must collectively sort it out for better understanding.

    A question can be closed by following means (any one of the below)..

    1. Either the question is well answered.
    2. or it is admitted that the question is still under research.
    3. or the question is meaningless and bereft of any scientific basis.
    4. or the querist is simply a moron who fails to understand the simple scientific language.
    5. or the answer to the question is beyond the proved intelligence of querist.

    In my previous response to 'origin', a related issue of cause-effect got created, let us see how we resolve it, but certainly none of the 5 parameters above get satisfied as on date.
     
  22. paddoboy Valued Senior Member

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    Correct....So?
    Scientific theories are models of reality, or as close to reality as we can get....
    Scientific models have set applications and regions in which they are correct.
    Newtonian gravity is correct within its domain, and gives required results.
    If we were to use GR within the domain that we use Newtonian, we would get the same result, albeit with far greater precision, that is not really required in the Newtonian domain.

    GR gives a more realistic picture of gravity being the warping and curving of spacetime in the presence of mass.
    But again, so what?
    Your questions in the main have either all been answered, other then a couple that make no sense...at least in the non scientific way you have presented them.
     
  23. OnlyMe Valued Senior Member

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    The fundamental cause of gravitation is not yet known. That is largely what much of the work on quantum gravity is attempting to work out. Keeping that in mind in the larger context of experience we do know that mass is associated with gravitational fields and galaxies are composed of mass, so in terms of experience.., even though we cannot say what the fundament origin of gravitation is, we do know with some certainty that the mass of galaxies do cause/create gravitational fields.

    Though it is a common modern interpretation of GR that the curvature of spacetime causes gravity, that remains an unproven theoretical interpretation of GR. Emphasis on theoretical! It is not known.

    It would seem to me that the only thing we can say with any certainty (or one of the things we can say with certainty), about the curvature of spacetime or as you put it distortions of space and Gravity, is that the curvature of spacetime accurately describes observations we associate with gravity. That is not the same as causing gravity.
     

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