eli5 If matter cannot be destroyed or created, how does space constantly expand?

Question

Maybe I’m misinformed about this. But I was always told matter cannot be destroyed or created. But I have been told space is constantly expanding. Is this expansion of space not made up of “matter”? Where does it come from?

In: 282

Answer 1

Isn’t the only thing expanding the observable Universe? That may not be the right term, but I mean it in the sense of “detectable”. For all we know another universe is expanding next to us and we simply haven’t run into each other yet.