liberalthought you should congratulate your class for asking one of the truly BIG questions since it is particularly a major stumbling block for String Theory or any other attempt to advance UInified Field Theory, such as Quantum Loop Gravity. Background independence is essential to any serious model of the Universe whether Steady State or Standard Model.
I found this helpful
Shape of the Universe - Wikipedia, the free encyclopedia
and also the books of Lee Smolin
Lee Smolin's home page
and the discussions on NPR between he and Briane Green
Lee Smolin and Brian Greene on "Science Friday" show Text - Physics Forums Library
