• Question: if the universe is expanding, what is it expanding into?

    Asked by a09jthwaites to Indi, Jarv, John, Ken, Vicky on 15 Mar 2012.
    • Photo: John Prytherch

      John Prytherch answered on 15 Mar 2012:

      It isn’t expanding INTO anything, it’s just expanding. To understand this, imagine that the universe is the surface of a balloon. When you inflate the balloon, the surface of the balloon expands. This is kind of what is happening in the universe, except in three dimensions.

      This is a tricky thing to understand (for me at least!), but astronomy and cosmology are amazing things to study.