If the centre of the universe was perceived as a bubble being popped, a big pop, the expansion of the universe could be perceived as the big pop still occurring, and the air contained inside the bubble is still emerging outwards like water against a beach, whilst the initial shockwave of the pop expanded faster than the air, so powerful it created a vacuum that is directed towards the shockwave at the edge of the universe. The space inside the bubble is the initial driving pressure, whilst the secondary pressure is the shockwave, the third being the residual energies expansion, the fourth being the vacuum of the shockwave itself, and the 5th being a host of resisting forces and everything inbetween other force connected, taking the energy transformations a long, finite, interconnected series of energy exchanges. Like a dot in the centre of a circle, the dot is the origin that produces the larger circle, whilst the lower dimensional circle is like a magnetic field that repeatedly grows in power to jump to a point that helps sustain it's field like a self sustaining forcefield capable of drawing power from itself and replenishing itself like a form of perpetual energy driven by a loop of creating and collapsing fields to create mini pops, spanks or resistance at point of convergence and field expansion direction, hence the expansion in all directions, starting with the path of least resistance. Think of this like a pair of magnets coming together at an accelerating pace the nearer they are together to converge, snapping together and collapsing the field inbetween that forces an energy exchange of the new unified field that displaces it according to it's field. The increased speed as the magnetic fields attract eachother are essentially creating more energy than put in. This could be perceived as something from nothing, or deposits of energy, masses created by the collapse of the field, comparable to pinching a finger that leaves you with a black mark. The black mark could be perceived as an antimatter deposit, a black hole mass with its own additional smaller field, or even a wormhole. The influence of the deposit (like a carbon deposit after burning fossil fuels in conventional combustion engines).