# What led to the electroweak and strong forces splitting?

Is the reason for the split believed to be spontaneous symmetry breaking? If so, did SSB occur because the Universe was cooling rapidly from extremely high temperatures?

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what makes you think they were "together" in the first place? –  Timtam Jul 30 '13 at 16:16
@ Timtam: Sorry, I know it is a theory and has not been proven –  curiousGeorge119 Jul 30 '13 at 16:18
How else would spontaneous symmetry breaking happen other than by cooling from high temperatures? –  BebopButUnsteady Jul 30 '13 at 16:38
@BebopButUnsteady: Thanks, I appreciate your comment! That is helpful, since I am not a physicist –  curiousGeorge119 Jul 30 '13 at 16:42
@Timtam ever heard about GUT models, that could have been relevant in the early universe or that could still be relevant at high enough energies? –  Dilaton Jul 30 '13 at 18:59

If the electroweak and strong forces do unify then it seems likely it would be broken by spontaneous symmetry breaking just as at the electroweak transition. This would happen when the average particle energies fell below around $10^{16}$ GeV.