Traditional Big Bang cosmology predicts a gravitational singularity before this time, but this theory relies on the theory of general relativity, which is thought to break down for this epoch due to quantum effects. Due to the extraordinarily small scale of the universe at that time, the quantum effects of gravity were the strongest and it is believed that cosmology and physics are assumed to have been dominated by the quantum effects of gravity. At this scale, the unified force is assumed to be unified with gravitation. Immeasurably hot and dense state of the Planck epoch is succeeded by the grand unification epoch, where gravitation force is separated from the unified fundamental force.