In the context of general relativity, space almost is a substance. It can bend and twist and stretch, and probably the best way to think about space is to just kind of imagine a big piece of rubber that you can pull and twist and bend.
Alan GuthThe recent developments in cosmology strongly suggest that the universe may be the ultimate free lunch.
Alan GuthThe Big Bang theory says nothing about what banged, why it banged, or what happened before it banged.
Alan GuthSpace is certainly something more complicated than the average person would probably realize. Space is not just an empty background in which things happen.
Alan Guth