If you want old school, think back to the defination of time-Space
Time is what happens when things in space change, Space exists where things change (paraphrase)
So assuming a leading edge from the big bang exists, at the outermost boundary would be the 'skin' of the universe. Nothing exists beyond it, no time/space. wee it possible to 'penetrate' that boundary, by defination you are bringing space/time with you and you would become the leading edge.
There is probably some supergravitational forces at work there. I wonder what the escape velocity for the universe is...
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There is another concept of the rippling universe, where the universe/big bang occurs from an infinately expanding universe, when the 'hollow' center or center point comes under enough 'vacuum' pressure energy from another/other dimensions leak into this universe causing another "Big Bang"... Therefore our universe is an infinate number of eternally expanding rings, like ripples in a pool when a water drop hits, which slowly burn out into nothing. Depressing isn't it. No grand collapse and pheonix like rebirth... just old crap fading away to make room for a new one.
