Overview of a Big Rip Theory
The hypothesis relies crucially on the type of dark energy in the universe . The type that could cause this hypothesis is a constantly increasing form of dark energy. If the dark energy in the universe increases without limit, it could overcome all forces that hold the universe together. The key value [ why? ] is the equation of state parameter w , the ratio between the dark energy pressure and its energy density . If w < −1, this dynamical vacuum energy is known as phantom energy , an extreme [ how? ] form of quintessence .