I think its possible that when the big bang took place that matter/enegry at the outer edge of the unfolding expansion were subject to asymmetrical forces restricting outward expansion. Its radiation inwards lead to a separation with inner matter Also, this matter had a restraining influence on inner matter. This unfolding scenario would result in a dense outer shell of matter at some distance from the known universe, containing ourselves and the visible galaxies. The rate of expansion of the outer shell would slow down (as per the expectations of earlier astronomers). Our inner part of the universe is expanding, and, to the amazement of astronomers, it transpires that the expansion is actually accelerating! This acceleration is caused by the gravitational attraction on the known universe by the outer shell of matter, that would naturally through time, slow down, stop and then begin to collapse.
If you consider the conventional view of the universe with regard to the accelerating expansion. This leaves a lot to be explained and I am not aware of any such attempt so far. This view is only slight less flawed than my above explanation. It would seem to me that in the absence of some unexplained driving force causing this acceleration, that acceleration of massive matter could not take place in an ad hoc manner. The simplest explanation that occurs to me is that the universe is under the gravitational influence of matter further out. One could consider a universe coming about through the initiation that was the Big Bang, and we are now experiencing the more gradual "Big Pull".

Thinking of these matters is taking up too much of my time. One would expect comfort from a better understanding of what it taking place, but the reverse is so. I am thoroughly confused now and would like to abandon all of this and get back into the real world. I am off for a shower, a cup of coffee and will resume the fight against the credit crunch. Sorry for all that silliness

I personally do not believe in the "big bang".
The Bible tells us that God spoke everything into existence.. the very first book of the Bible
Genesis

Thank you for your reply. I would dearly like to hold your beliefs, and I do respect good people that hold them.
I myself had a deeply religious childhood, and am familiar with the Bible. The Bible was probably acceptable in its own time. However, understanding of the things around us has moved on. I think sincerely that the Bible is deeply flawed-from beginning to end, so obviously so that I would not even begin to explain why.

God is the same yesterday, today and forever.
God Bless you!
Thank You for your opinion and taking time to reply

Thank you too. I wish you the very best. Cheers!

The current answer to the question you are thinking about, at this time is that the expansion is accelerating due to "something we have not yet identified". This is the only answer that science can give at this stage. We call it "dark energy".

Thank you for the reply Capuchin. If I added to the argument right now, my contribution would not be properly thought out and would be facile. Re the proposition that you kindly replied to, it was only an exercise in thought. I did back up the idea off script with my own logic (albeit, most likely weak in physics). I omitted these details in order to keep the submission brief.

Do you have a hypothesis on the subject?

I would agree with the current hpothesis that most of science agrees with, and that would be that some kind of energy which we have yet to measure pervades that universe and causes the expansion to accelerate.

I would like to talk about your hypothesis a little more. If you are considering a hollow spherical shell of matter outside of the observable universe, then I'm afraid you have missed a flaw - the gravitational attraction inside a uniform hollow shell due to the mass of the shell is 0 at all points. The result can be proven mathematically through integration.

Yes Capuchin, point taken. I take it that this is the same principle as centre of gravity. Would it be acceptable though to regard the whole of the known universe + more as the hollow interior of a sphere?

What immediately occurs to me as a defence of my hypotheseis is that large clumps matter above a certain size, due to gravity, will form into spheres. So, I would have to amend my idea by revisualising this outer ring of matter as a series of naturally formed spheres in one of the familiar forms, i.e. planet, star, Black hole, or indeed a vast mammoth galaxy. The circumference would be vast, and perhaps that would allow individual gravitational attraction to extend some distance in our direction.

Also, the physics existing outside the sphere would be unknown as would its influence on each of the spheres and might make this inward gravitational field more feasible.

I have read of dark matter and dark energy. Have astronomers proposed any explanation of how dark energy might impart this acceleration to matter?

Keep always in mind, that it is not the matter or the structures that expand, but the room (the Universe), itself. There are theories
To explain the "cold spot" in the CMBR that include a dust shell outside the Universe.

And just to make your life a little worse...

Well, that redshift we think comes from expansion... not necessarily must come from expansion! There are cases, where the explanation of the redshift as a Doppler shift (due to the expansion) has been questioned due to uncorrelance. On the other hand, sure the Cosmic Microwave Background and stuff are supporting an accelerating Universe, but there are alternative cosmologies, that many people forget about, and get no funding for further development. The Big Bang theory, is only a theory, with so many free parameters, that you can almost fit any truth, without that the Big Bang, is the Truth. It already fails at many predictions.
(Do not use the Bible as a source of science.)

Also, sometimes things like Dark Matter and Dark Energy, are ways of adding components to fit an non-working theory. First astrophysicists come up with a theory, then it doesn't work, but the theory is so good, that astronomers don't want to abandon it, so let's simply invent "dark matter" or "dark energy" to keep the chosen model. I suggest you to read some about MOND (Modified Newtonian Dynamics).

The more parameters you add to a model, the easier, it is to fit anything to it.