Question:
If the universe is expanding, what is it expanding into? In other
words, how does one define the universe?
Replies:
By definition, Universe includes everything
therefore there is no question of its expanding into something.
An example which is easy to grasp is that of surface of a balloon.
If we were two dimensional creatures restricted to surface of a balloon then we
will see the "Universe"(balloon) expand. his example does not convey the whole
richness of possible universe, as there can be universes which are infinite in
spatial extent which can stretch as time goes on. No matter how much stretching the universe goes
through, it can not have a size larger than infinite !
If you would like further explanation just drop an e-mail.
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