Your kind of contradicting yourself, if the space is infinitely large how can it be in our heads. You maybe interested to learn that when you travel at the speed of light, the entire universe condenses into the width, dependent on the direction of travel, of less that of a carbon-carbon bond, but since the universe shrinks as do you proportionally, so when you are moving at 3.0X10^8 m/s in the shrunken universe you are really moving hundreds of millions of times slower. Now theoretically when you BREAK the light barrier you actually tear through space time and enter the multiverse, which is filled with floating membranes. VERY THIN, very fast moving, lots of energy. Now every membrane is comprised of an equal amount of energy, which according to E=MC^2 mass is made of energy, so mass doesn't exist. Every membrane is a separate quantum state, so any possible quantum state is present in one of the membranes, there in fact exists every quantum state imaginable. Now this falls apart because if one was to imagine the multiverse as a space, similar to real space, and in the real space we are apart of we can move at the speed of light and the universe will condense dependent on the direction of movement, but when you enter the multiverse you are no longer moving at light speed inside a universe, so once you break space time because you are conciously observing multiple universes, and when you observe ours at a still speed it is infinitely large then, either every universe will grow infinitely large instantaneously or else they will cease to exist. So one must imagine that either the multiverse does not act like a space, or this is all in our heads.
Now there is a phenomenon called Schroedinger's uncertainty principle that states if a conscious observers isn't checking on the status of an event or object, you are unable to tell what the object is doing, and its not that you are just unsure of where or what the object is doing it is that the object is everywhere at the exact same time. This is followed by the measurement problem or wave particle duality claiming that if an object, or event is moving at light speed it is moving so fast that you can only tell one variable about its travel, so if you know how fast its going you don't know where it is, but if you know where it is you can't tell what speed its going. Which is then further substantiated by entanglement which states that if you take two electron and place them at opposite sides of an area and effected one in some way then they would both respond identically and simultaneously, this is brought on by the idea that if everything was once one, or currently is one, then any action to a part will effect the whole. This is M-theory in a nutshell, but I believe this will be obsolete very quickly, with the work going on across the world and at CERN is astonishing and I really wish I could be a part of it, but alas I don't have a degree.
Now it is possible to think that inside the multiverse our physical quantum states would break down causing the observer to be destroyed before an opportunity is made to observe, or that when the observer breaks through space-time he would immediately enter a new space-time. Even that nothing exists and "...we are all one consciousness experiencing itself subjectively." -Bill Hicks. That the space-time we live in is merely a continuous loop of reality that we craft with the one consciousness we are and the universe is, that there is a conscious force behind everything and that the other quantum states are merely ones will to change the current one. But what I have found, don't subscribe to any one concept of universe, life or experience, because everything we really know is merely speculation, based on assumptions. Even science, because can we really trust the electro-chemical reaction that takes place when light from a computer screen enters our eyes and we see these words, or are you just crafting the entire experience as it happens to you. Feel happy everyday, don't dwell on the past because life is short, we don't really know what to think and you may only have this time to experience what is, so take everything with a grain of salt.
Peace
, Man I love this Stuff.. Just picked Up Michio KaKu's Hyperspace, Time to Catch Up