Theory: Life in a bubble

I'm sure this theory is old, but, here you go, anyway:

"What if, the entire universe was made-up of different chambers. What if, in the center of a galaxy, there was the center of the chamber, made up of very dense stars that, together, create enough gravity to keep the galaxy together.
Now, imagine that each galaxy was encircled with some kind of glass; something to keep beings of that galaxy from contact, and to keep from losing gases and/or other planetary material. That would be a waste [to lose those]."

Now, imagine the first extra-galactic space-ships unknowingly piercing that "glass", and the even bigger suction of whatever the stuff around the galaxies is, pulling everything in our galaxy into the void, tearing every single thing in our galactic home apart.

Ouch? We'd probably not feel, or see it, depending on how fast the sucking goes.

I have idea for a story: what if, a space-faring civilization unwittingly already punched that hole, but the suction is so slow, that so far, it's only the outer "glass" that's come off.

Maybe that's why we can see other galaxies... But this is probably just sci-fi thinking on my part.