Vibration is the root function of polarity throughout all of existence. Everything that exists vibrates, because everything that exists is both a polarized expression of Consciousness, as well as is made of further polarized expressions of itself.
Remember that the Forces of Nature are the Forces of Consciousness. They are not meant to be understood in purely physical ways. In fact, they are not meant to be understood in any physical way. The Forces of Consciousness are not of the Physical Nature, but of the Spiritual Nature, which is the cause of the Mental Nature as effect, which is the cause of the Physical Nature as effect, which in turn, always serves to validate the will of Consciousness, thus perpetuating the cycle.