If you are at all familiar with layperson explanations of such things that the professionals give, you have probably seen the analogy of an expanding balloon to explain our expanding universe. I understand that analogy, but it has always left me with a huge question. Galaxies, and glactic clusters. it is explained, are depicted as dots on the surface of the balloon, and as the balloon inflates, all the dots grow further away from each other. So that no matter what dot you might be observing from, you will see the same basic thing....all other dots moving away from you, as though, as Carl Sagan put it, you had committed some cosmic blunder. So far so good.
But what is INSIDE the balloon? It might well be only a case of my being rather daft about that, but I don’t get that part. Then, I watched this video. It further confused me because it depicts, not just galaxies on the outside surface of a balloon, but a sphere FULL of galaxies, galactic clusters, etc. So, which is the more correct way to see “our” universe...are we and everything we can know just as ants crawling about on the outside skin of a vast balloon? Or is “our” universe a sphere, full of such things? And where are we relative to the rest of it?
Thank you in advance, for your enlightenment.
TRB