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Physical theory a pre-requisite for asking questions?

  1. Jul 3, 2012 #1
    Physical theory a pre-requisite for asking questions??

    Should a physical theory be a pre-requisite for asking questions in modern physics???
    Both of my previous threads were locked and received lot of criticism because i asked regardind a space-craft moving faster than c, I would just like to point out that there is a mathematical description of a universe in which particles travel faster than c, and also i would like to point out the "THE BLACK SWAN EFFECT", so if there is a new phenomenon, should we rather not examine it because "THERE IS NO PHYSICAL THEORY TO EXPLAIN IT" or should we develop new theory to explain this phenomenon.
    Should we not encourage new theories just because they lack proof or due to other reasons!
    William cowper said that:
    "Absence of proof is not proof of absence"
    I also want to know "Is discussing of physical theories which do not have any credible evidence like String theory or Quantum theory of Gravity allowable in this forum??"
    If yes, i really dont get the difference between why asking question which are not supported by any physical theories not allowed while physical theories which do not have any experimental backing being allowed to discuss???
     
    Last edited: Jul 3, 2012
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  3. Jul 3, 2012 #2

    micromass

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    Re: Physical theory a pre-requisite for asking questions??

    Your thread has been sufficiently answered. There is currently no experimental evidence of particles going faster than light (that I know of), so there is no need for a physical theory. So what you have asked is going against mainstream physics and we have pointed that out.

    If there is a physical theory out there that is published in mainstream journals and that allows for particles going faster than c, then you can start a thread about it. But if you ask whether what happens if a spaceship goes faster than c, then the only correct answer we can give is: it can't (according to the current understanding of physics).
     
  4. Jul 3, 2012 #3
    Re: Physical theory a pre-requisite for asking questions??

    I posted the initial thread because i was of the same opinion as you guys regarding the space-craft travelling faster than c but was surprised when the same scenario was used in the chapter Special Relativity of the book "Concepts of modern physics" by Arthur Beiser to explain the very fact nothing can travel faster than c, so i wanted to clarify regarding this and hence i posted that thread!
     
  5. Jul 3, 2012 #4

    micromass

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    Re: Physical theory a pre-requisite for asking questions??

    Well, we gave you an answer. It is an experimental fact that nothing can go faster than c. There's nothing more that can be said about it.
     
  6. Jul 3, 2012 #5
    Re: Physical theory a pre-requisite for asking questions??

    Basically, yes.

    A hypothetical situation (or thought experiment) has to be constructed from and within what is current knowledge. The whole point of it is to present a situation and then analyze its results and implications. That process can't function if the basis for the hypothesis comes from outside current formalisms because there will be no constraints on the possible mechanisms one can come up with, and no basis for supporting or denying them in present knowledge.

    Don't confuse a hypothesis that goes against current knowledge with a "new phenomenon".

    Many folks in this forum are highly trained and experienced in analyzing things like this. One of the first things they will do in examining a hypothetical situation is check to see if any assumptions are not met to determine if it is in violation of current knowledge. Sometimes this is not so clear at the very edges of what is known and unknown, but the basic "c check" is going to be the first one in the relativity forum.
     
  7. Jul 3, 2012 #6

    PAllen

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    Re: Physical theory a pre-requisite for asking questions??

    If you want to reference such a mathematical model, and e.g. ask about how its consequences differ from the known universe, this might(?) be ok, but you have to reference it first. Honestly, how can the question get any answer in principle otherwise.
     
  8. Jul 3, 2012 #7
    Re: Physical theory a pre-requisite for asking questions??

    Then what is given in the book is wrong??
    Its hard to believe that a book and author of such repute will make such a grave mistake!!!!!
     
  9. Jul 3, 2012 #8

    micromass

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    Re: Physical theory a pre-requisite for asking questions??

    You never actually cited the book. It is more likely that you misunderstood what is says.
     
  10. Jul 3, 2012 #9
  11. Jul 3, 2012 #10

    phinds

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  12. Jul 3, 2012 #11

    micromass

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    Re: Physical theory a pre-requisite for asking questions??

    If you want to start a thread to ask questions, then you need to give us all the information.
    If you ask "What will happen if this spaceship moves faster than c", then the only answer we can give is that spaceships don't move faster than c.

    If you would have added that you read something in a book that you didn't understand and if you gave us the relevant passage, then our answer would be very different.

    You can never give too much information in your post.
     
  13. Jul 3, 2012 #12
    Re: Physical theory a pre-requisite for asking questions??

    I'm reading Shrödingers Kittens by John Gribbin right now and in order not to come across as a crackpot I'll quote:
    This led to speculation that there might be particles that travel faster then light (called tachyons), but there's no experimental evidence of their existance.
     
  14. Jul 3, 2012 #13

    PAllen

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    Re: Physical theory a pre-requisite for asking questions??

    Conventionally interpreted, it does say no. Adding the feature of particles with imaginary mass, you have tachyons. A rocket (made of ordinary matter) will never exceed c (per the theory). A tachyon must alway move greater than c. If tachyons can interact with normal matter, a variety of causality issues arise (for which various solutions have been proposed - in the speculative realm).

    Upshot: none of the is relevant to the original question of rocket presumed to be made of ordinary matter.
     
  15. Jul 3, 2012 #14

    micromass

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    Re: Physical theory a pre-requisite for asking questions??

    This question has been answered.
     
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