How will the universe end?
It should be noted that neither theory is mere idle speculation. Theoretical scientific exploration on this topic was made possible by General Relativity, which could be employed to describe the universe on the largest possible scale. Mathematically there are many solutions to the field equations of General Relativity, depending on how much matter there is in the universe, each implying a possible ultimate fate of it. Alexander Friedmann offered some of those, and a few included the possibility of the Big Bang. Experimental evidence surrounding the expansion of the universe from Hubble and co. were also extremely helpful. Generally, the theoretical decision between Big Freeze and Big Death depends on how much matter-energy there is in the universe, which in its turn determine what kind of geometry it has. If the universe is finite but unbounded, and matter-energy is much more sparsely scattered through spacetime than we supposed, then the universe may assume the hyperboploid shape nece
