This question already has an answer here:

Experts agree that the stuff within the universe is moving farther apart from all the other stuff in the universe--much like the dots marked on the outside of a balloon that is being inflated. We know however that a balloon expands into the space around it. If we think of our universe as a balloon, then, into what is it expanding? Is it possible to know the answer to that question for certain?


marked as duplicate by John Rennie, Rob Jeffries, user36790, Kyle Kanos, RedGrittyBrick Oct 21 '15 at 10:39

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • $\begingroup$ You shouldn't take analogies so seriously. The universe isn't like a balloon, even if things are expanding away from each other "like on a balloon." $\endgroup$ – Asher Oct 21 '15 at 0:11
  • $\begingroup$ I think this previous post answers your question, so I flagged your question as a duplicate. $\endgroup$ – eyqs Oct 21 '15 at 2:59
  • $\begingroup$ The previous posts essentially sum up to mean "we don't know because we don't have the tools to answer that question & we don't know what happened before the BB (Big Bang) nor where the energy came from at the origin of the BB." The truthe is, we don't even really know the extent of space. All we can see is the Doppler shift to calculate the expansion speeds. The whole expanding into space or making new space-time as it goes, appears to be purely speculative. $\endgroup$ – DIYser Oct 21 '15 at 19:11