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Pastpaper on GR

  1. Oct 11, 2005 #1
    I am studying general relativity now and I want to collect some pastpaper about general relativity. Could you mind share yours with me? :blushing:

    yukyuk
     
  2. jcsd
  3. Oct 11, 2005 #2
    Here's one I like - http://xxx.lanl.gov/abs/physics/0204044

    Pete
     
  4. Oct 11, 2005 #3
    It would be better to learn from papers that haven't been rejected in peer review. Papers aren't normally for teaching general relativity anyway, so I would actually suggest looking into general relativity texts from creadible modern authors that understand invariance. Taylor and Wheeler are good authors for example.
     
  5. Oct 11, 2005 #4
    He didn't ask for papers that were rejected in peer review. And I wrote that paper while I was working with Taylor on his text Exploring Blkack Holes.

    Pete
     
  6. Oct 11, 2005 #5

    pervect

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    It took me a little googling, but I eventually realized that yukream was probably actually asking for exam papers.

    As far as Pete's paper goes, I'm not terribly surprised he likes his own paper. Personally, though, I think that students would be better off learning the modern view first (which Pete doesn't seem to like very much), and saving a study of Einstein's original views after they have understood the modern view.

    I have a few alternate recommendations - Baez's paper comes to mind, and Carroll's lecture notes. I'll edit this post to put the links in a little later. Since the O.P. was probably interested in exam papers, it may be a little moot. Still, it couldn't hurt to recommend some other introductory GR papers in the thread.

    [add]
    http://lanl.arxiv.org/PS_cache/gr-qc/pdf/0103/0103044.pdf
    http://xxx.lanl.gov/abs/gr-qc/9712019
     
    Last edited: Oct 12, 2005
  7. Oct 11, 2005 #6
    That was a joke of course since everyone likes that work that they've done which they're willing to let others read. Nothing I've ever written has anything different in it than the work of Einstein (except when it came to mass - But there Einstein contradicted himself so...). It is only different than what you call "modern literatrure" which purports to claim what Einstein actually states in the literature. I'm not happy with the writing though so I'll have to redo that one of these days.

    re - "Personally, though, I think that students would be better off learning the modern view first (which Pete doesn't seem to like very much),..."

    Woa! Please don't put words into my mouth. What I don't like is somone saying "Einstein said such and such..." when Einstein never really said that. Also there is a tendancy for students as well as even teachers to come to erroneous conclusions when this so-called "Modern view" is taught.

    So why is it that you believe that pervect?

    re - "and saving a study of Einstein's original views after they have understood the modern view."

    The problem is that students never go back to see the so-called "original views" which the students actually believe that is what they are being taught in the first place. I recal one instance where a paper actually got publihsed into the American Journal of Physics in which the entire article is wrong. All because the writer thought that he knew what Einstein really said. Students never go back to the source to find the truth. I only know of one person who's done that and he's an Einstein Historian (former head of the Einstein papers project).

    Pete
     
  8. Oct 12, 2005 #7

    pervect

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    I think that the modern view reduces errors. It also definitely facilitates communication when all parties have the same view.

    There is another point as well:

    The Christoffel symbols depend on the choice of coordinate system because they aren't tensors. The Riemann is a tensor, so it doesn't have this problem. Hence the emphasis on the Riemann as the coordinate independent way to describe the gravitational field.

    The Christoffel symbols IMO provide the best bridge between Newtonian gravity and GR. Unfortunately, they have problems such as have arisen in the "moving mass" discussion, when there is not a natural choice of coordinate systems - because of their coordinate dependent nature.

    On the flip side, though, if everyone thought in exactly the same way, we probably wouldn't progress very fast.

    Taking all the factors into consdieration, I'm for a unified modern approach to teaching relativity (and other subjects), but it's always good to have a few mavericks out there.

    A lot of physics is taught in ways that are considerably different from the way it was first formulated or discovered. Feynman makes a point of this in many of his popular books. I'm not terribly interested in the history myself, but I gather that Maxwell's equations were not originally formulated with vector calculus, but quaternions. I don't think that there is any need to go back to using quaternions just because that was the way that Maxwell originally formulated his equations, howeer, I think the vector notation is clearly superior.
     
  9. Oct 12, 2005 #8
    Pervect
    you really very clever! Yep ~ What i mean is the past exam paper!!:smile:

    yukyuk
     
  10. Oct 12, 2005 #9
    pervect - Did you read that paper that I posted? Also please remind me, has this topic arisen here before? If so then did you want to disucuss it yet once more?

    Pete
     
  11. Oct 12, 2005 #10

    pervect

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    Yes, I read the link you posted - I skimmed it the first the through, and I read it again in a little more detail just now (I still didn't put it under a microscope).

    The main point I want to make is that Christoffel symbols require one to define a coordinate system before they have any meaning.

    The accelerating rocket observer is a case in point. If we specify a point in a flat space-time, the Riemann curvature is always zero. We do not have to specify any more information than the point (x,y,z,t) to define the Riemann curvature at that point. When the space-time is flat, this curvature is always zero.

    But if we specify a point in a flat space-time and ask what the Christoffel symbols are, we do not have an answer until we specify the motion of the observer by defining his coordinate system. An observer on a rocketship imposes a different coordinate system on the same flat space-time and has totally different Christoffel symbols than an observer who is not accelerating. So specifying a point (x,y,z,t) is not enough information to define the Christoffel symbols in a flat space-time - we need more information. This "extra" information is the coordinate system of the observer.

    That's phase 1, I suspect it's not very controversial.

    Phase 2 is where we apply this reasoning to the question of "what is the gravitational "field" of a moving mass", and we ask "OK, what coordinate system do we use", since we have agreed in phase 1 that the answer depends on the coordinates.
     
  12. Oct 12, 2005 #11
    You didn't answer my question. Do you want to discuss the paper I wrote? I have only two days left online then I'm getting off the internet at home and will rarely use it elsewhere .... I hope.

    Let me point out that there is a big part that you're missing here - The observer. Whether there is Lorentz contraction, the presence of an electric field, etc. will always depend on what the observer is doing. So why do you now leave the observer out here? The presence of a gravitational field is an observer dependant phenomena. Recall what Einstein said
    I fail to see what you find so objectionable to a gravitational field whose existance depends on the observer. Observer dependant quantities are found throughout relativity. So why does it bother you so much?

    Pete

    ps - Its the metric tensor which represents the gravitational field and, of course, its a tensor.
     
    Last edited: Oct 12, 2005
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