Yeah, I wonder that too. Is there a bottom? Is there a ceiling?! Is this part of an infinite fractal Universe that actually extends without limits to ever-smaller and ever-larger scales?

Okay, so this is by no means a new theory (
http://www.amherst.edu/~rloldershaw/ifu.htm),
1. No edge or boundary to the universe
2. Time is infinite
3. No limit to size scales
From my experience only, this universe we currently 'reside in' does have limitations, a boundary in other words. Many years ago now I was interested in finding out how big our universe is/was. Because it is easy to project in awareness I sought an answer, and it became obvious when I reached something very much like the skin of a bubble that was porous. So I moved through the 'skin' only to find that what existed outside this universe were gazillions more bubbleverses.
From this I recognized the old saying of "As above so below" as being a real Truth and not just another new-agey throw out line.
Time is only a relative experience, in itself it does not exist. All there really is, is the NOW. Nothing 'before' or 'after' is real no matter 'where' you are perceiving from.
And yes, there is no limit to scales. I traveled outside our universe, entered another, and have been 'somewhere' where all the bubbleverses could be perceived as something very much like sea-foam, or a conglomerate much like any Galaxy is and all existant things are.
Lastly, I could see that 'new' bubbleverses are created constantly from the touching of other bubbleverses which give off so much energy that they appear just like a big bang. This made me wonder if each universe was a being, in the same way that we are born into 'existence' here, and in the same way that we can consider Earth to be a being. And, by taking the maths to 11th dimension we can see it allows for exactly the types of bubbleverses I experienced.
Thanks for the opportunity to share this info.