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Why smaller particles come together

  1. Aug 27, 2010 #1
    --- >> a question…… it is said that a few seconds after the big bang , the subatomic particles gradually lost energy and came together…….then why the protons and neutrons came together first and not the electrons ?……….. i thought ,this is possibly due to their greater mass….. but further dividing them , they are also made up of smaller units…… why these smaller units came came together…….. the main question is why the smallest particles came together and turned to the form they are in now…… obviously at very very high energy of that time they could exist individually………then what were the forces that caused them to come together……. ???

    ……………….. as far as the forces on small particles are concerned they are short range and with enough energy in them why would they settle............ and if those forces came to bind them .. then where such forces arose from..
  2. jcsd
  3. Aug 27, 2010 #2


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    Read Steven Weinberg's "The First Three Minutes".
  4. Aug 31, 2010 #3
    Protons and neutrons attract each other with the strong nuclear force, whereas electrons only attract to protons with electromagnetism. The strong nuclear force is stronger than EM, so the temperature you need to cause nuclei to fall apart is much higher. To heat things enough so that nuclei fall apart, you need tens of millions of degrees, whereas atoms will fall part with a few thousand.

    Why the forces are what they are is a much more difficult question, and it's something that isn't fully understood. For things like nuclear fusion, you really don't need to understand why to see what happens since you can just heat up a reactor and see what happens.

    For much, much hotter temperatures beyond current experiments, you need to start understand the reasons why things are what they are, and at that point you hit the limits of our current knowledge.
  5. Sep 1, 2010 #4


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    Binding energies. We have experimental evidence that tells us how much energy it takes to tear neutrons, etal, apart. We infer from this particles are unstable at these energy levels. We extrapolate backwards to the point in time conditions [temperature] were sufficient to preclude them from forming and remaining stable.
    Last edited: Sep 1, 2010
  6. Oct 10, 2010 #5
    if i combine the property of possession of charge with the size of the mass.....
    is there any regular patter between them....

    and what is charge actually and where does it come from.....
    as far as i have studied in my books , charges can be separated by polarization .... so what should be the smallest point of charge ..... and what kind of mass it should posses...

    here wat should be the force that holds the charge together.....
  7. Oct 13, 2010 #6
  8. Oct 14, 2010 #7


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    The physics necessary to answer your question are unknown. It lays at energy levels that are not yet experimentally accesible.
    Last edited: Oct 14, 2010
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