Is the expansion of the universe after the big bang just the the "uncurving" of space time from an inconceivable point? And if so, is the loss of energy that curved it that much the only thing that could allow it to "uncurve"? I hate to use the word loss of energy, but i'm not for sure where the energy that could curve the entire universe to a single point could go. Also, can or has anyone calculated the energy it would take to curve the observable universe in on itself. Thanks.