Original sentence: The most commonly held view is that the universe was once a gravitational singularity, which expanded extremely rapidly from its hot and dense state.While this expansion is well-modeled by the Big Bang theory, the origins of the singularity remains one of the unsolved problems in physics
Edited sentence: According to this theory, the universe was once a gravitational singularity, which expanded extremely rapidly from its hot and dense state.While this expansion is well-modeled by the Big Bang theory, the origins of the singularity remain one of the unsolved problems in physics