However , as these become diluted , the cosmological constant becomes more dominant and the expansion of the universe starts to accelerate rather than decelerate .
At first , the expansion is slowed down by gravitation attracting the radiation and matter in the universe .
As these become diluted , the cosmological constant becomes more dominant and the expansion of the universe starts to accelerate rather than decelerate .
At first , the expansion is slowed down by gravitation attracting the radiation and matter in the universe .