Question: People talk about the universe as expanding/contracting which suggests there is an 'egde' or 'end', what is beyond the edge? how would you describe this idea of nothingness?

Philip Ratcliffe answered on 19 Nov 2014:

Well, no there isn’t an edge in the sense we normally mean. But it’s very hard to mentally picture what that means – I and I think most of my colleagues can write down the mathematics but we can’t really understand it in a describable way. Physics is like that – we are good at picturing things we see and touch every day, but some things, like quantum mechanics and cosmology, are beyond our direct reach.
In any case even something that has infinite extension can still be expanding or contracting – the distance between to objects increases or decreases (like currants in a currant bun while it’s cooking).
Nothingness is very difficult to contemplate; I think some Greek philosophers felt that it was actually impossible.