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Thread: The Physics Journey

  1. #1 The Physics Journey 
    Moderator Moderator Markus Hanke's Avatar
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    "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."
    - Prof Stephen W. Hawking

    True words from a great man. I recently came across this quote on Facebook ( of all places ), and it had a profound effect on me. Learning physics is a journey, and the greatest pitfall on that path is always the illusion that we know and understand something, whereas in fact we do not. It is all too easy to fall into this trap without even realizing it.
    In the last week or so in was involved in a discussion with our very own member Farsight which spanned several distinct topics, from GR over SR to QFT, QED and electromagnetism. It was all relatively basic stuff, nothing to sweat over since I would usually consider myself fairly knowledgeable in those subjects. And then, in the middle of this discussion, and after having seen above quote by Prof Hawking, it suddenly hit me :

    If I am so knowledgeable in all these subjects why the *%# do I always have Wikipedia open in a separate browser tab ???!

    I never really consciously thought about this, it is just something I have always done. I am jumping back and forth to Wikipedia to check on stuff which really I should know about and understand by heart. This was a bit of a wake-up call, and not one of the pleasant kind. Fact is that I profess knowledge in areas which I am really not all that confident in. A quick self-check confirmed that I have gaping holes in my understanding of even some basic ( classical ) areas of physics, a fact that I was quite taken aback by.

    So what to do ? I am not scientist by trade; regrets aside, I have chosen another career path and that is it. I am too old to go back to university, and my family depends on my income anyway. Besides, I don't want the pressure of exams, thesis and assignments. I have a family with kids, and no time for all that.
    So what is my motivation, really ? I want to understand. That is it, that is why I am here, and all those other forums, and that is why I trawl through textbooks and do battle with differential forms, tensors, path integrals and Langrangian densities. That is why I keep reading arXiv papers, play around with Maple and WolframAlpha, and loose myself in Hawking's scientific publications. I want to understand the universe better, I want to understand why the universe works the way it does, and ultimately how I myself as a conscious being relate to what I perceive the universe to be. It is all about understanding and expanding our consciousness in the process.
    Will I ever be able to make any kind of serious contribution to theoretical physics ? Highly unlikely, in fact I would go so far as to say "impossible" - I am certainly not kidding myself here. But really, that is not what it is all about - I only want to know, to understand.

    So what's the solution ? There's really only one thing to be done here - get down and dirty. I can't go back to university, but no one can stop me from bringing the university to me ! A quick search confirmed that there are excellent learning resources out there, in fact many institutions publish substantial parts of their course materials online. At the very least one gets the listing of textbooks used in the actual courses. And so it starts - calculator, several reams of scrap paper, pens, pencils, a notebook to start a table of formulas, and an hour or two every day to put my head down and study. Having purchased the textbook for MIT's first semester physics course I have now started again right at the beginning - classical mechanics. From there I will go on, and slowly work my way through, all the way to the end, which are the graduate and post-graduate courses for advanced physics topics. It's going to take time, and stamina, and sweat, and oh boy is it going to be boring and labourious at times, but hey, the rewards are great, and since I do not have the pressure of class schedules and exams pushing me, I can take things at my own pace and work around my family and job commitments. And I have all the time in the world. It's going to take years, but so what ? I want to stop deluding myself, and really understand. Hawking was right, nothing worse than a mere illusion of knowledge.

    Interesting times ahead my friends here on TSF, I can tell you


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  3. #2  
    Universal Mind John Galt's Avatar
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    Markus, there is one other thing you don't understand: the depth of understanding that you already have. I am in awe of your dedication to knowledge, your skill at communicating that knowledge and your restless quest to improve your own understanding and that of others. I shall never understand 1/10th of what you do about physics and maths, no matter how down and dirty I get. That's not a negative view, just objective reality. But that's OK, there are other domains in which I can learn and develop. I'll leave the physics to you and just watch from the sidelines. Thanks for all the great matches so far.


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  4. #3  
    Moderator Moderator Markus Hanke's Avatar
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    Quote Originally Posted by John Galt View Post
    Markus, there is one other thing you don't understand: the depth of understanding that you already have. I am in awe of your dedication to knowledge, your skill at communicating that knowledge and your restless quest to improve your own understanding and that of others. I shall never understand 1/10th of what you do about physics and maths, no matter how down and dirty I get. That's not a negative view, just objective reality. But that's OK, there are other domains in which I can learn and develop. I'll leave the physics to you and just watch from the sidelines. Thanks for all the great matches so far.
    Ha, ha, thank you
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  5. #4  
    Brassica oleracea Strange's Avatar
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    Nice post there, Markus.

    I also hate it when I get sucked in to talking about things I don't know as much about as I should. Or expressing things with more certainty than is warranted (but it gets tedious prefixing everything with "to the best of our knowledge", "the evidence seems to indicate", "our current best theories suggest that" and so on)

    Quote Originally Posted by Markus Hanke View Post
    If I am so knowledgeable in all these subjects why the *%# do I always have Wikipedia open in a separate browser tab ???!
    I'm not sure you should worry about this. I am in the habit of double checking things even when they are on a subject I am supposed to know in detail (i.e. not science).

    Will I ever be able to make any kind of serious contribution to theoretical physics ?
    Well, as a certain posters like to say, "it needs an outsider with a fresh view". The difference is, you are putting in the groundwork to have the understanding most of those people lack. You never know, you may come up with a novel insight. The fact that you are not having to spend your time teaching and doing/managing research projects might give you the freedom to do that.

    Or maybe not.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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  6. #5  
    Moderator Moderator Markus Hanke's Avatar
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    I'm not sure you should worry about this. I am in the habit of double checking things even when they are on a subject I am supposed to know in detail (i.e. not science).
    True, but I just feel I am relying too much on outside sources instead of on my own knowledge and understanding. But maybe that's just me

    Or maybe not.
    Ha ha, precisely
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  7. #6  
    Moderator Moderator Markus Hanke's Avatar
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    I'm right in the thick of it now, and to my amazement I am discovering how much fun classical mechanics can be !!! Consider this gem from the exercises section of my textbook :

    "A monkey escapes from the zoo and climbs a tree. After failing toentice the monkey down, the zookeeper fires a tranquilizer dart
    directly at the monkey. The monkey lets go at the
    instant the dart leaves the gun. Show that the dart will always hit
    the monkey, provided that the dart reaches the monkey before he
    hits the ground and runs away."

    Would anyone fancy to have a go at this ? This is of course very simple high school level stuff, and it is obvious that the dart always hits without having to do any maths, but I am still finding it incredible fun !!
    Hard to believe the difference a few years of "maturity" can make - in my school days I was always really bored by classical mechanics, now I am enjoying it


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  8. #7  
    Moderator Moderator Markus Hanke's Avatar
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    Three weeks in, and still going strong
    Three quarters through classical mechanics now...
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  9. #8  
    Moderator Moderator Markus Hanke's Avatar
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    Three months in, and I'm still at it ! The going is getting a bit tough now, though - not easy to juggle a full time job as well as family and kids with studying. I'm still at Young & Freedman's University Physics, just to get a solid grounding. I can tell now that it simply is not realistic to study everything in depth; once I am through this introductory course I will probably have to specialize and pick out one or two areas which I then pursue intensively. Those will likely be Relativity and Particle Physics ( SR, GR and QFT ). We shall see. The important thing is that I haven't given up yet, and I have no intention to...right, enough gossip, back to Maxwell's equations
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  10. #9  
    The Doctor Quantime's Avatar
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    The biggest question one can ask is 'Am I wrong?' I hate asking that question but it is a brilliant eye opener. Myself I have taken great strides in understanding in physics specifically; cosmology, astrophysics, GR and SR, particle-physics, some string theory, and of course the wacky world that is QT. I have never until recently been interested in mathematics in general but I am increasingly finding myself drawn to the subject, the universe is amazing, and what better way to understand its language than to learn physics.

    It all started one night for me when I was thinking about the universe and anti-matter, I postulated the existence of an anti-universe, my thoughts went on from there and here I am today. My quest is to understand the theoretical framework in which time travel is possible and indeed FTL, my curiosity branched then onto QT and how incredible it really is at describing nature. I too have great gaps in my understanding and knowledge, physics is riddled with understanding and its roads can take you to the destination you want, but often leaving you driving back to where you came from on another! With the system repeating!

    I am curious though I noticed your 'Location' you put a Calabi-Yau Manifold. What in the sense are you familiar with that? I came to learn it from an interpretation of the dimensions done by Rob Bryanton on 'Imagining the tenth dimension' If you haven't seen it I recommend it it is brilliant. I would love to share your thoughts on the way he explains the ten dimensions in the way he describes them Markus.

    Imagining 10 Dimensions - the Movie - YouTube
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    "If you wish to make an apple pie from scratch, you must first invent the universe". - Carl Sagan
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  11. #10  
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    Quote Originally Posted by Markus Hanke View Post
    I'm right in the thick of it now, and to my amazement I am discovering how much fun classical mechanics can be !!! Consider this gem from the exercises section of my textbook :

    "A monkey escapes from the zoo and climbs a tree. After failing toentice the monkey down, the zookeeper fires a tranquilizer dart
    directly at the monkey. The monkey lets go at the
    instant the dart leaves the gun. Show that the dart will always hit
    the monkey, provided that the dart reaches the monkey before he
    hits the ground and runs away."

    Would anyone fancy to have a go at this ? This is of course very simple high school level stuff, and it is obvious that the dart always hits without having to do any maths, but I am still finding it incredible fun !!
    Hard to believe the difference a few years of "maturity" can make - in my school days I was always really bored by classical mechanics, now I am enjoying it


    I had a physics professor in college who did a demonstration of this in an auditorium. He had a target (not a monkey) that fell from the top of the stage at the same time he launched a dart. It always hit the target, no matter the speed of the dart.

    I think the explanation is that the motion of the dart is the vector sum of the horizontal and vertical motion. The horizontal position is just the horizontal component of velocity multiplied by the time of flight. The vertical position is the vertical component of the initial velocity, multiplied by the time of flight, minus (1/2)gt^2. The vertical component mulitplied by the time of flight is just the height of the monkey in the tree. The monkey's position is just -(1/2)gt^2.
    This would be a lot clearer if I weren't too lazy to use Tex.
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  12. #11  
    Moderator Moderator Markus Hanke's Avatar
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    Quote Originally Posted by Quantime View Post
    The biggest question one can ask is 'Am I wrong?' I hate asking that question but it is a brilliant eye opener. Myself I have taken great strides in understanding in physics specifically; cosmology, astrophysics, GR and SR, particle-physics, some string theory, and of course the wacky world that is QT. I have never until recently been interested in mathematics in general but I am increasingly finding myself drawn to the subject, the universe is amazing, and what better way to understand its language than to learn physics.

    It all started one night for me when I was thinking about the universe and anti-matter, I postulated the existence of an anti-universe, my thoughts went on from there and here I am today. My quest is to understand the theoretical framework in which time travel is possible and indeed FTL, my curiosity branched then onto QT and how incredible it really is at describing nature. I too have great gaps in my understanding and knowledge, physics is riddled with understanding and its roads can take you to the destination you want, but often leaving you driving back to where you came from on another! With the system repeating!

    I am curious though I noticed your 'Location' you put a Calabi-Yau Manifold. What in the sense are you familiar with that? I came to learn it from an interpretation of the dimensions done by Rob Bryanton on 'Imagining the tenth dimension' If you haven't seen it I recommend it it is brilliant. I would love to share your thoughts on the way he explains the ten dimensions in the way he describes them Markus.

    Imagining 10 Dimensions - the Movie - YouTube
    I must admit that my knowledge about String theory and Calabi-Yau manifolds is spotty at best - which is one of the reasons I have started this whole learning process. I can't really comment on it any further until I have watched the video, but it is close to two hours long, and I really don't have time tonight. I'll pencil it in for the weekend, and come back to you then
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  13. #12  
    Moderator Moderator Markus Hanke's Avatar
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    Can anyone recommend a good introductory textbook for quantum field theory ? I am looking for something that starts at the very beginning and focuses on the fundamentals, taking things slowly. Pretty much all QFT textbooks I have seen thus far are simply way over my head in terms of the maths used, and I am not too proud to admit that fact. I need something which takes me slowly through canonical and path integral formalisms. I am not looking for a complete and in-depth treatment of the subject, but rather for something specifically geared towards a first time ( university ) student looking to master the basic principles on which QFT is build. For me as a newbie to the subject the focus needs to be on understanding and the physical content, rather than mathematical rigour.

    Any recommendation will be highly appreciated. Thanks in advance !

    P.S.: I already have a working knowledge of quantum mechanics and the maths involved in it ( though I'm of course not an expert ).
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  14. #13  
    Moderator Moderator Markus Hanke's Avatar
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    I am curious though I noticed your 'Location' you put a Calabi-Yau Manifold. What in the sense are you familiar with that? I came to learn it from an interpretation of the dimensions done by Rob Bryanton on 'Imagining the tenth dimension' If you haven't seen it I recommend it it is brilliant. I would love to share your thoughts on the way he explains the ten dimensions in the way he describes them Markus.

    Imagining 10 Dimensions - the Movie - YouTube
    Ok, I have had a chance now to watch this.
    I am really not sure though what to think of it. I think an appropriate term might be thought-provoking. It is an interesting concept, trying to visualize dimension in this way, but - does it actually stand up to further scrutiny ? For example, the idea of the many-worlds interpretation being connected to a fifth dimension is intriguing, however, if you take a look at the paper referenced :

    http://arxiv.org/pdf/1105.3796v3.pdf

    it is really more of a thought experiment than any type of proof. For example, it is not obvious why such a dimension would appear compactified.

    But in any case, there are some interesting ideas in the video which are well worth further thought, so long as one remembers that the author is not a physicist.
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