When it's snowing on a not so cold day, we can se the snowflakes fall to the ground as big chrystals, forming a wet sheet. After a while the flakes, or parts of them, melt to water, forming water-spots, later to unite into a small pond.
The frosen water therebye creates its own space, into which it expands.
I think this is how the universe is growing. Light emits from all stars in all directions constantly. Along the way the photons get distorted and lose some of their "density", and their "melted" energy then forms the surrounding, expanding space.
Take away the energy completely, and you take away space. But as that's not possible in reality, surrounding space-energy must fill the gap, therebye creating the effect of gravity. Objects move closer to each other because the distance between them is narrowed by their "hunger" for energy.
Where does the energy go? It goes into the objects, adding to their radiation of magnetic fields or light emitment. It then is cast out into the energy-ocean again. Therebye we have a natural cycle of light.
That's the "easy" part. The hard part would be to explain into what the emitted energy goes beyond the borders of the universe. How can something expand into nothing?
I'll try. Could this nothing be a virtual reality, a thought-frame into which the energy can "materialize"?
It should be something like that, because when one think about the edge of the Universe, one must conclude that a universe isn't possible.
The more I think about what's behind the edge, the more unreal it all seems. The universe can't be limited, because if there's nothing outside of it, universe is all. And yet, if it has a volume, it can't be unlimited.
So, the only solution would be that the Universe couldn't have come to existense, unless through a Creator, who by His mind shapes the room for it to enter.
Without His creative mind, expanding into nothingness wouldn't be possible. Nothing can go into nothing, unless nothing is something after all. And that something would be the virtual, or spiritual, thought-frame of God.