Probably at about the time of the “Big Crunch”, which is when some astrophysicists argue that the universe will collapse in on itself. While the universe is still exanding, this expansion seems to be slowing down. It may be that this rate of expansion will stop, then the gravitational forces of the entire universe will cause all matter to be drawn towards a single point – a very big crunch indeed. Its not certain this will ever happen, but given that we’re still expanding, then it must be more than the age of the current universe away – probably much more than 20 billion years in the future.
What will happen “after” this … well, given that time won’t exist, as we know it, this is a difficult question to answer. However, it was “ever” to happen again, then I think it will be after a crunch.
Of course, outside our Universe there could a continuous process of big bangs that we’ll never know anything about, because we seem to be trapped in this Universe … sounds like a good introduction to a movie:
“In a Universe, far, far, away …”
(or is that a breach of copyright?)
An interesting debate going on here!
As Keith mentioned, one theory of what will happen next involves the ‘big crunch’, where the universe contracts. A further theory is that all of the particles as they contract will revert to their original location – making it possible that the big ban happens all over again. If this occurs, then it is fairly plausible that those particles will interact with each other in exactly the same way – making the whole of history happen again and again for all eternity…
That then raises questions about fate… if this theory is correct (is it only one of hundreds of theories), then is this the first ‘cycle’ of history (so you get to make your own decisions, and you will make them again and again for all eternity) or has this happened before – so you would have made the choices you have made anyway, and they could never have happened any other way…
Something to think about 🙂