reportman said:
Thanks Marcus. I am VERY new to all of this. But at least I'm trying!
Sure and my guess is that you will not have any substantial trouble. there are a lot of people at this site here that can help, answer questions, offer different approaches to understanding.
My personal favorite approach, which might not work for you, is to temporarily step down into a lower dimensional world where everything is 2D. Get to understand what expansion cosmology would mean in that toy version, and then try to extend that understanding back up to the 3D case. Don't rush yourself, get familiar with the 2D "diagram" of it first.
Google "wright balloon model" and watch the animated diagram as it expands
and imagine that all existence is concentrated on the 2D surface of a balloon
there is no inside or outside to the balloon. Everything that is, is there on the surface including small flat 2D creatures like thin amoebas sliding around on flat 2D planets circling 2D stars in paperthin 2D galaxies.
You can see the galaxies in the "wright balloon model" movie, and you can see little lightwaves wiggling along thru 2D space, across the balloon surface traveling between the galaxies. The galaxies stay in the same place relative to each other, they do not move latitude-longitude-wise, the distances between them just get bigger. In this 2D animation diagram only the lightwave wigglers move and they always travel the same speed across the surface
the link to it is also in my signature at the end of this post where it says "...wright/Balloon2.html" so you don't need to google it.
What was happening at the very very beginning of expansion is a somewhat more complex question. There is some indication that there might have been a contracting balloon (to put it in terms of the diagram) that got down to a critical size where contraction forces briefly reversed and caused it to rebound and start expanding. But there are various competing ideas. No need to rush, get to understand the expansion process more thoroughly first. Not an explosion. No surrounding space. Space itself expanding, you might say, and no space outside of space for it to expand into.
That is the conventional standard cosmic model. It might be wrong (any scientific theory might) but it is the simplest best-fit most reliably predictive model devised by people so far. Works extremely well and build solidly on General Relativity (our theory of how gravity and geometry operate) which has been well-tested. Good to understand the mainstream model even if you hope it will be improved on eventually.
