Playdo said:
Hmm. So we are on the verge of a pangenesis? If he universe started from a single point, and space time are unfolding from that moment, are you saying space and time were instantly infinite although matter may not yet fill that infinite possibility?
Going back to the front here is the universe was once a super dense single point what was it embedded in?
When we talk of the expansion of the universe are we not talking about a time evolving system of matter and energy. If the Big Bang came from a point is there not a place somewhere out thee were only the very oldest photons have managed to reach? Would'nt that be the boundary of the physical universe?
I have heard talk of theorems that say perhaps the universe simply popped up in some pangenesis type of exitation of the vacuum. Some of the people who like that one are religious, but I won't let that color my opinion on the matter.
You have the wrong picture, you imagine matter condensed in a point and then spreading out. That is not what the Big Bang is about. It's not the matter that spreads out in space, but space "stretching out".
And our observable universe came out from a very small region of space (but still not a point) but this says however nothing about how large the region was that started expanding (in theory it could be infinite).
The universe, wether we imagine it to be finite or infinite, has no boundary or edge.
There is a lot of work done on cosmological theories that emerge from vacuum states.
But first bring in mind that the vacuum we are in fact talking of is not just emptiness, far from! The vacuum, even in the deepest and remotest voids we know of, contains matter, energy, fields and particles.
Realy, one has to see vacuum as something filled with particles, energies, fields and so on, and not as something empty and devoid of matter/energy.
Second, there are at least two vacuum states, one with an energy density of zero and another with a field potential of zero. They are distiguishable states, often referred to as the "false" and "true" vacuum state.
The theories you might have heard about are about cosmic inflation.
Cosmic inflation is about a small patch of space in a "false" vacuum state embedded in a "true" vacuum. It acts in a peculiar way in that the force of gravity turns out to be repulsive instead of attractive, and causes the false vacuum bubble to rapidly expand in a very brief moment. During this rapid expansion (called 'inflation') the energy density of this expanding bubble remains the same, which is another curiosity of this vacuum state: the energy density can not change rapidly, yet the bubble itself grows enormous in size in a very brief instant.
At the end of inflation we then have a small sized bubble which has grown from the size of a proton to the size of a grapefruit almost instantanious, and which contains enormous amount of energy. This energy concent is released in the form of particles.
After the inflation ends the normal hot big bang scenario begins in which the hot dense and small bubble keeps expanding in a more modest rate and becomes larger, less dense and cooler, until the conditions are fit for (re)combining protons, neutrons and later on atoms.
There are a whole bunch of cosmic inflation scenarios. Some scenarios allow inflation to go on forever.
For more information, do a Google search on "cosmic inflation" "Alan Guth" or "Andrei Linde"