“…one of the continuing debates among astrophysicists regards whether or not the universe is closed i.e. will not expand forever.
On the one hand, the model of a closed universe holds that there is sufficient mass in the universe so that the Big Bang explosion will gradually slow down and reverse due to the pull of gravity. In this model, all the mass of the universe involutes back into its unimaginably small and dense original condition until another quantum shift precipitates another explosion.
On the other hand, there are those who contend that the supernova data on distant galaxies confirms that there is insufficient mass for the reversal to occur, and that the negative expansion energy of space is causing our universe to expand forever.”
–Daniel Feldman, Qabala: The Mystical Heritage of the Children of Abraham, 2001, pg. 131.