The observable universe is constantly expanding as the passage of time allows light to reach us from more and more distant parts of the universe. So it’s less “we don’t know what’s outside” and more like (to a certain extent) “we have to wait and see.” And there’s nothing we’ve seen to indicate that these external regions that are being revealed are anything but more of the same kinds of things in our inner region of the observable universe.
The observable universe is constantly expanding as the passage of time allows light to reach us from more and more distant parts of the universe. So it’s less “we don’t know what’s outside” and more like (to a certain extent) “we have to wait and see.” And there’s nothing we’ve seen to indicate that these external regions that are being revealed are anything but more of the same kinds of things in our inner region of the observable universe.