so, I have this neat setting idea for a book, that relies on a couple concepts -- mainly a universe with a different set of physics-- But I'm wanting to make it seem less "fantasy" and more "sci-fi" so I'm looking for notes, suggestions or cool stuff such a universe I propose would imply that I didn't think of.

This is the best way I can describe it's physics. It'll sound a lot like nonsense, or even "alchemy" but that's where you come in hopefully.

1. instead of space being a vacuum, it is a universe sized ocean of "Umbra". A combination of the concepts of emptiness and water. A base material of the universe itself, even though it is essentially "Nothing" but as if Nothing was more like what we describe as water. It exerts pressure, can be seen through, and the more of it there is, the harder it is to see through.
2. The other sort of... dualistic element of this hypothetical universe is a sort of antithesis of it that combines the concepts of Light with that of Air. (I know this all sounds really fantasy so far, just bear with me please lol) -- But it is called Caelux. It pushes against and repels Umbra at the smallest level -- and the zone wherein the Caelux interacts with the Umbra is affected with a force much like Gravity -- Where things are pulled to the center where this force interacts on either side. In this way, "Planets" or any Celestial body in this universe is a bubble composed of Caelux pushing against the Umbra. Beings inside a bubble will have an environment a lot like Earth, but they are on the inside of a sphere.
3. Bubbles themselves have at their center a ball of dense Caelux and another substance called "Zeal", that is akin to the concept of fire and electricity but as a... physical substance I guess? Anyway, the center of a bubble of Caelux is like... super far from where it meets the Umbra. Like the distance from our planet to the sun.


...(continued)