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The four forces that are trying to be unified by TOE?

  1. May 16, 2012 #1
    Hi guys basically I'm in secondary school and my teacher started taling to me about the four forces in space which are tryin to be unified by TOE and the Grand unification theory. She said that at my level I don't need to know what they are and she said that she wouldn't go into them in depth. What are these forces? All my teacher told me was that there is a "strong one and a weak one".

    My apologies if this is posted in the wrong section as I am not entirely sure what I am talking about.

    Any help would be greatyl appreciated. :)
  2. jcsd
  3. May 16, 2012 #2
    The four forces are the strong, weak, electric and gravitational forces. The names of them are actually the strong and weak (I've heard electro-strong and electro-weak used for them too but not all that often)
    Electric and gravitational forces you should already know about.
    The weak force is related to beta decay and isn't really that useful in our day to day lives, the strong force is the one that keeps quarks together.
  4. May 16, 2012 #3


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    They are actually the strong and weak nuclear forces (and more correct to say electromagnetic, not electric force). The electroweak force is not a synonym for either the electromagnetic or the weak force -- it is the unification of the two. At high enough energy (around 250 GeV if you're counting), the electromagnetic and weak nuclear forces become unified into the electroweak force -- they are no longer distinct interactions. At even higher energies, it is expected that the electroweak force and the strong force unify under a framework that is typically referred to as the Grand Unified Theory, or GUT. The term "electrostrong" is not commonly used, if ever. Exactly how this Grand Unification comes about is still not fully known, although certain approaches using an extended symmetry of nature, known as supersymmetry, have been most successful.

    All this still leaves out gravity. It is much less understood how gravity joins the fray, or whether it even should be expected to.

    In summary, there are 4 fundamental interactions (or forces):

    1) Gravity
    2) Electromagnetism
    3) Weak Nuclear
    4) Strong Nuclear

    2) and 3) have been successfully unified; this interaction is the electroweak force (by successfully unified, I mean that a consistent theory has been worked out that is in good agreement with data; the ongoing search for the Higgs boson at the LHC -- in the news recently! -- is the final piece of the puzzle.)
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