Where's the Nearest Edge of the Universe?

So, after definitively answering in a previous blog about the center of the Universe, I was then asked by my brother where the nearest edge of the Universe might be located. (He enjoys taking long road trips.)

Is there an edge or boundary of the Universe?  Unfortunately, we are limited in how far out into space we can see.  There is probably more beyond that distance…but that light hasn’t had enough time to travel the distance to earth just yet.

Since we don't know for sure whether or not the universe has a boundary, scientists have a few theories:  

a)  The universe is a closed universe, curving around on itself.  Hence, no boundary.

b)  It is infinite in size…hence no boundary.

c)  There is “dark flow” on the outside of the observable universe which generates massive gravitational forces, causing our rapid expansion.

d)  String Theory calls for multiple universes, each it’s own space-time bubble.  The interaction of these “bubbles” causes disturbances in the force, such as Big Bangs. 

The universe that we can observe (by using the Hubble ultra deep field detector) is around 90 billion light years wide.

If you want to travel to the observable edge, the best I can offer is:  turn left at Pluto….and take an extra sandwich, it make take a while to get there.

Some references and further reading:

http://www.fromquarkstoquasars.com/what-lies-beyond-the-edge-of-the-observable-universe/

http://www.cfa.harvard.edu/seuforum/faq.htm#s1