Hi Steve; I sort of agree with Neurtralino, in that nothing exist " outside " of the universe, but I agree more with you and I that nothing is called the VOID. This allows for universal expansion, but simultaneously, as it's expanding it becomes the universe, consequently and theoritically the void does not and cannot exist in our reality. The universe being the size of the Earth at 1 second doesn't fit our current model. Apparently the universe is 156 Billion light years wide even though it's onle 14 Billion years old. The latest theory is spatial inflation where within 10-35 to 10-32 seconds the universe expanded exponentially. Inflation Theory 
According to the latest cosmological model, the universe sprang into being about 14 billion years ago. At birth, the space was likely to have been curved and warped due to quantum effect within the tiny speck and time may be meaningless. After about 10-35 seconds, there began a brief period of exponentially fast expansion, known as inflation, that ironed out any curves or warps in space and made the universe flat (because it becomes so large). Inflation also predicts a much smaller initial region, which is required for smoothing out the distribution of matter and radiation, only leaving behind tiny quantum fluctuations that match the observed spatial variations in the cosmic microwave background radiation and provide the seeds for galaxy formation
Best to all, Pat P.S This expansion means the universe ( Space ) was expanding far faster than light speed. ( Another Mystery )