According to traditional Big Bang cosmology, the electroweak epoch began 10 seconds after the Big Bang, when the temperature of the universe was low enough (10 K) for the electronuclear force to begin to manifest as two separate interactions, the strong and the electroweak interactions. (The electroweak interaction will also separate later, dividing into the electromagnetic and weak interactions.) The exact point where electrostrong symmetry was broken is not certain, owing to speculative and as yet incomplete theoretical knowledge.