Hi. I posted this in another question similar to yours. It was easier for me to copy and paste it, sorry if it doesn't answer your question completely. But you are welcome to email me with any question.
Here it is:
There is actually another school of thought on this and is gaining wider acceptance and popularity.
It is my preferred theory and the one I generally refer to and subscribe. It is the "Superstring Theory"
This theory suggests that our Universe is like a big amoeba-like structure called a "membrane". We are one of possibly an infinite amount of other membranes. Noone has attempted to calculate or come up with a formula as to how many membranes may be immediately surrounding us.
The distance to each membrane is close to each other in relation to the size of each membrane (which may be near infinite in size) and every few eons or so two membranes could collide with each other causing a massive explosion ("Big Bang") in each membrane causing in instantaneous destruction and recreation of all matter in each membrane, thus causing in essence a new Universe.
This may have happened an infinite amount of times in our eternal past and may continue to happen in our eternal future.
Moving on. To my understanding there is a supermassive black hole in the center of our galaxy. It is alternately and erratically being fed by material and debris circling the edge of it. It goes into a feeding frenzy the suddenly stops and goes into a dormant period when there is a gap between the matter being consumed and the next mass of material. Waiting to be pulled in close enough to begin the next feeding frenzy.
It has been theorized that every galaxy has a supermassive black hole and that it may have been essential in forming a galaxy. I can't recall the specifics about the reasoning behind it, but I am certain that this was asserted.
~jaz~
Actually here is another post of mine copied and pasted :
I subscribe (unless a better, more plausible and accepted thoery is brought forth) to the same school of thought roger m introduced. That is "String Theory", also known as "Superstring Theory" or even "M theory".
It basically postulates that all matter is made up of vibrating open, curved, or closed looped energy strings vibrating at different harmonics. It also posits that an enormous closed loop string which vibrates in a manner that closes all points around it, looking like a giant amoeba and is termed a "membrane" is what our Universe may be.
This theory also lends the idea that there may be an infinite amount of nearby (in terms of grand scale, because traversing this nearby distance would perhaps take the lifetime of our Universe) membranes and that sometimes, in eons, two membranes could collide and producing the effect we know as the "Big Bang" destroying and recreating all the matter in our Universe. Which is probably the mirror effect in the other membrane.
As to what is in between the distance of the membranes only mathematical equations and our imagination could only speculate.
I'd like to think it is vanilla pudding....rofl.
~jaz~