Imagining Universe and Black Hole

Ever imagined what if we assume the universe is to water, and the black hole is to bubble? What is beyond the universe, is as if a fish asking what is beyond the water? What if the space we know has a mass that is relatively insignificant to us, and beyond space there is another mass with lower density that we cannot reach? When water is heated with enough energy, it evaporated in the water itself and bubble is formed. The supernova could have done the same to space we know, creating so much energy that "boiled" a space bubble?
In this case, the vacumm space that we know may not be perfect void, it is just filled with matter of even lower density undetectable with any instrument. Then, the dimension theory has become philosophical. Is dimension no longer refers to the space, it becomes the degree that human beings is able to detect and react with the surrounding as an observer. The point at where no event can be observed by human being is considered void. then how many dimension is out there? The hypothesis is infinite. But this is an un-testable hypothesis. Nonetheless, the testing is not necessary as it would be meaningless to explore the dimension we can't exist in, can't observe and can't act upon.