Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Is the number of strings constant?

  1. Jun 15, 2011 #1
    Hi,

    Can someone please tell me if current versions of string theory assume (or perhaps result in) a conservation of the number of strings in the universe? Just like conservation of matter and energy.

    If my lunch is made up of tiny vibrating strings, was it the same strings that existed during, say, the period of inflation in the early universe? If they just filled a different role back then.

    Also, can string theory explain such changes in matter and energy over long periods of time? The formation of new elements, new molecules, DNA, etc.

    Thanks
     
  2. jcsd
  3. Jun 16, 2011 #2

    Demystifier

    User Avatar
    Science Advisor

    The number of strings is not conserved. One string may split into two strings, just as two strings may fuse into one.
     
  4. Aug 19, 2011 #3
    so vibrating strings of infinet volume and no demention can be spit and join together? and if so how can you "spit" something that has no dementions? or for that mater how can they join together if there litrally nothing. 0+0 is still 0 not 1 and vise versa..... your answer causes more questions then answers.
     
  5. Aug 19, 2011 #4
    Where did you read this. Have you a reliable source?

    Strings typically have one dimension, and branes are two dimensional.

    As posted above, there is no conservation of strings.

    You can think of it this way: strings constitute both matter and energy (like radiation)....and than can morph from one to the other....by breaking apart and combining....for example, Hawking radiation can be thought of as a string segment (a loop, a twist) breaking away from the horizon....
     
    Last edited: Aug 19, 2011
  6. Aug 19, 2011 #5
    The elements actually formed after the period of inflation....during inflation whatever matter may have existed was likely ionized.....and remained so until about 380,000 years after the big bang.....elements up to iron are created in stars, but heavier elements require supernvoa explosions.....

    If you subscribe to the never ending universe, for example the Turok-Steinhardt model, then I think many if not all of the elements have always been here....perhaps subject to formation via stars and supernova....
     
  7. Aug 22, 2011 #6
    what kind of energy? It cant both have mass and energy if the strings have only one demention, mass is a three dimentional mesurement of lenth, width, and height. in order to have mass you need all three dimentions. you can not say that a two demention plane has mass because it is infintly thin. as enstine showed mass and energy are the same without one you cant have the other
     
  8. Aug 23, 2011 #7

    Demystifier

    User Avatar
    Science Advisor

    Have you ever heard about the Dirac delta function? I guess not ... :uhh:
     
  9. Aug 23, 2011 #8
    Mass does not require dimension. Take for example the electron, it is a pointlike particle and hence have no spatial dimensions but it does have a mass.
     
  10. Aug 23, 2011 #9
    if it is "pointlike" but not a point then just becuase its consitered a point does not mean it is. i still hold the same thought mass is a mesurement of three dimentions. in your next post if you disagree with this geive a reliable source.
     
  11. Aug 24, 2011 #10

    Demystifier

    User Avatar
    Science Advisor

    Someone who never heard about the Dirac delta function could not understand such a source. If you want me to give you such a source, please convince me that you understand the Dirac delta function.
     
  12. Aug 31, 2011 #11
    the dirac delta funtion, to my understanding, is that it is zero everywhere but at zero this is all i know about it though i am only 17 and would like to learn if you would EXPLAIN what it is and not just shoving me to the side like a wothless peice of knowlege. how can it be zero every where but at zero and in what way dose it aply to string threoy? if you could send your reply in a private message.
     
  13. Sep 1, 2011 #12

    Demystifier

    User Avatar
    Science Advisor

    Awhalen, I have sent you a private message.
    For more math see also
    http://en.wikipedia.org/wiki/Charge_density
    especially the section "Discrete charges".
    Everything what is said there for charge can also be said for mass.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook