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Cosmology for dummies

  1. Mar 30, 2005 #1

    Chronos

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    Being lazy by nature, I am always on the lookout for new papers that dip far enough below the technosphere to be comprehended by mere mortals - without descending to the tabloid level. This recent entry makes my 'must read' list:

    http://arxiv.org/abs/gr-qc/0503107
    Understanding Our Universe: Current Status and Open Issues
     
    Last edited: Mar 30, 2005
  2. jcsd
  3. Mar 30, 2005 #2

    Math Is Hard

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    Thank you for offering some crumbs to those of us who make up the great unwashed masses. :biggrin:
    Teasing aside, it does look very interesting, and seems to encompass a lot of things that newcomers to A/C would like to read about.
     
  4. Mar 30, 2005 #3

    Chronos

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    Sheesh, if I like it, it must be easy to digest. Thanks to MIH for over estimating my power curves. Really though, this is a great read and makes it possible, even for low wattage bulbs like me, to connect the dots between the big questions.
     
    Last edited: Mar 30, 2005
  5. Mar 30, 2005 #4

    marcus

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    I agree with Chronos and MIH about this (not-awfully-mathematical) overview of cosmology.
    It is worth publicizing, as Chronos did by starting a thread on it,
    because it might be useful to more than a few PF people.
    I put some additional comment here:
    https://www.physicsforums.com/showthread.php?p=506857#post506857

    Padmanabhan is good, but it is still reasonable to want further explanation: I hope people still have questions after reading it that they want to discuss here! :smile:
     
  6. Mar 31, 2005 #5
    The author of the article seems fluent enough in his knowledge of general relativity and astrophysical cosmology but when he states near the end of his article that no one has "any idea how or why the universe was created." (?) There seems to be a general lack of a GOOD BOOK he has missed reading.
    love and peace,
    (kirk) kirk gregory czuhai
     
  7. Mar 31, 2005 #6
    let me be a little more gentle and polite please. i did not mean to be insulting but it has seemed to me for a long time that Physics and most of Science in general is nothing more than for better or worse just some kind of statistical curve fits to experimental data!
    in the case of the whole universe, this seems pretty awful clear with now about 100% of the energy/matter of it NOT DESCRIBED AT ALL excepte VERY CRUDELY by
    some hand waving curve fitting and differential equation screwing around.
    pleese! what a life some of you Physics guys have! wow!
    love and peace,
    and,
    peace and love,
    (kirk) kirk gregory czuhai
    http://www.altelco.net/~lovekgc/kirksresume.htm
     
  8. Mar 31, 2005 #7
    i mean after all, the author states that the main inflationary phase of the universe
    of the universe took place mostly at smaller distaces than the Planck length and he thought that this might be easily be verified someday soon!
    Although he also states that all attempts, string theories, additions to the langrangians, fudgin' of the cosmological constant, etc. etc. and etc. are not worth a hill of beans towards explaining anything about why the 100% of the Universe is the way it is.
    Well some of you have some ideas as to why I am why I am the way I am do you not?
    love and peace,
    and,
    peace and love,
    (kirk) kirk gregory czuhai
     
    Last edited by a moderator: Apr 2, 2005
  9. Mar 31, 2005 #8
    go away quickly.
     
  10. Mar 31, 2005 #9

    Math Is Hard

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    welcome to the forums, Kirk Gregory. I won't be as terse with you as matt.o because I believe that your intent here was not malicious. That said, I don't think that your immediate and lightly-analyzed objections will have much sway here with the regular posters to the Astronomy and Cosmology forum.

    The folks in this group have spent an incredible amount of time studying this subject and their collective knowledge is more than you or I could ever hope to achieve in a lifetime of study. I suggest you approach a little more gingerly, and with an open mind, if you really want answers.
     
  11. Mar 31, 2005 #10

    Chronos

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    kirk, I think the author is merely being a good scientist by stating the obvious without appealing to a higher authority. Attempting to understand the 'mind of God' [as Hawking put it] is not the same as taking issue with it. I would, in fact, call it the most sincere form of flattery.
     
  12. Apr 2, 2005 #11

    Nereid

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    Let me add to MIH's welcome Kirk; I hope you find Physics Forums a place where you can discuss physics, and astrophysics and cosmology in particular.

    Please do take the time to read our guidelines; specifically note that we have a strong policy regarding discussion of religion (this website is not the place for any such discussions), and that we do have a vibrant Philosophy section, where discussions concerning the nature of science, and what aspects of reality there might be beyond those accessible to the scientific method (for example) are welcome.
     
  13. Apr 2, 2005 #12

    Nereid

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    I have moved Kirk's interesting reply to a new thread, in General Philosophy, here.

    My thanks to marcus and Chronos for telling us about this Padmanabhan paper. :smile:
     
  14. Apr 2, 2005 #13

    Evo

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    That is a great link Chronos. As long as I can remember, I wanted to become an astronomer. My first life altering experience was when, as a small child, I visited a Planetarium. I was hooked. I got a telescope, read everything about it, watched every documentary. My dad killed my dreams with his refusal to allow me to go into this field when I entered college. :frown: I wish I'd had the guts to say no to him.
     
  15. Apr 3, 2005 #14

    Chronos

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    But you never lost your sense of wonderment, did you? We all have tales of regret. I merely refuse to yield.
     
  16. Apr 3, 2005 #15
    ok religion aside!?
    somehow (soon?) does not the article say something about that it should be not too hard to make measurements verifying that most of the expansion that took place in the inflationary phase of the universe history took place at distances less than the Planck length. (pray?) tell how (in the _____) is this going to be done?

    Also does not the author before the end of the article say that NO scientific theory says anything about how or why the universe started at all, how barionic matter that we are most familiar(?) with was initially formed, no one knows WHAT the >95% of the Universe the dark energy IS AT ALL!
    ALL THAT TIME AND BRAIN POWER for the last twenty years spent fiddlin' with strings, branes, manifolds, topologies, lagrangians, differential equations TO WHAT USEFUL PURPOSE? Is it not more math than physics so therefore the original article under discussion here does not belong here at all but in some math forum right?
    love and peace,
    and,
    peace and love,
    (kirk) kirk gregory czuhai
    http://www.altelco.net/~lovekgc/Britney.htm
    p.s. am i going to get another warning from someone in my mail?
    how much free speech does this newsgroup have anyway?
    such sensitivities! omg! lol (:-o) !
     
  17. Apr 3, 2005 #16

    Nereid

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    Would you be interested to go through the article, and discuss this? If so, please quote the passage where you read this 'something about'.
    Indeed.
    I guess this partly depends on what you consider a 'useful purpose' to be; if you're looking for a way to solve world hunger, then cosmology won't help; if it's an answer to religious questions, then cosmology won't help; if it's how to 'get rich quick', then cosmology won't help; if [you get the idea, I'm sure].
    So what do you consider to be the criteria for distinguishing 'math' from 'physics'?

    IMHO, FWIW, the paper was about cosmology, and this section of PF is about cosmology, so it seems this is a good place to discuss it.
    Hmm, when you registered to become a PF member, I think you were asked to agree to the rules and guidelines of this forum, were you not? If any of those were unclear, please let us know (we have a 'Feedback' section); there are many who would be pleased to explain them to you. In the meantime, why not sit back and enjoy the show?
     
  18. Apr 4, 2005 #17
    for further explanation: p. 12 of the P. article discusses that its predicted from the math that most of the inflation occurred at distances less than the Planck length and that this could be checked from the resulting density flunctuations that would lead to the lead to the anisotropies of the universe in theories and observations.

    for everyones information, i too enjoy gazing at stars just for the sake at gazing at stars! and i certainly do not wish to get kicked out of the Physics Forums! PEACE!

    What is the difference between math and physics? That is not really my concern with the P. article. I am more concerned with how empirical and resultant full of assumptions the mathematical models presented in the cosmologies presented seem to have become despite how poorly they describe what they are to describe!
    NOT that I could do better!

    But judge not therefore not be judged! So I am, I suppose getting a taste of what I deserve. I thereby offer my apology right here for offending anybody and all by my lack of forsight and even rudeness.

    These thoughts and my genuine wish for love and peace and peace and love for you all perhaps will get me another warning and maybe to the delight of some of you will be my final statement on this "Comology for Dummies" topic!
    love and peace,
    and,
    peace and love,
    (kirk) kirk gregory czuhai
    http://www.altelco.net/~churches/BlueRoses.htm
     
  19. Apr 5, 2005 #18
    i could be accused of lying now since i think i have thought of one more more comment important enough to mention.
    since most of the expansion during the inflationary phase of the universe's existense is said to have occured at less than Planck distances that would mean it occured in less than a measurable period of time.
    therefore how could it ever be be quantified?
    peace and love,
    and,
    love and peace,
    kirk
     
  20. Apr 5, 2005 #19

    Chronos

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    Physics, as we know it. breaks down at the Planck 'wall', which occurs at 10^-43 seconds after the big bang. You are correct in noting we cannot quantify anything prior to that first tick of Planck time. Inflation, however, was only just beginning, not ending at that time. Inflation persisted until at least 10^-35 seconds after the big bang. The universe we can currently observe was a whopping 15 cm in diameter by then.
     
  21. Apr 6, 2005 #20
    But Chronos as i read p. 12 of the P. article in PDF format, it is shown and discussed that MOST of the inflation OCCURED AT PLANCK DISTANCES even though yes the universe for the most part was much larger for the most part during that time so my argument still holds.
    peace and love,
    and,
    love and peace,
    kirk
     
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