There are two forces at play in the universe that impact and shape mass. They are gravity, the attracting force, and it's counter, repelling force, absence. Remove absence from the equation for a moment. Picture the universe as different sized marbles placed on a trampoline. If the quantities of mass in the universe in any one area break beyond a certain level of density, or in the sake of our trampoline, are heavy enough to impact the surface tension of the trampoline... ie are heavy enough to indent it, the mass will pool together in a central point. Eventually, if not for a few potential equilibriums being met, whereby a balance is achieved in the mass being equally dispersed so that all symmetrically attract all others, the entirety of the mass will eventually pool together. In this model on a universal scale, if gravity is the only attracting or repelling force, eventually everything would pool back together into a Big Crunch. ...