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Setup:

Let's assume we have a giant ball of water in space.

Magic: Lets assume the water does not compress its center under its own gravity. (Constant density of 1 g/cm^3)

Basic stuff:

The mass of this ball of water, (since it does not compress) is directly proportional to its Volume, which is proportional to the CUBE of ball's radius(v = 4/3Pi r^3). (mass aprox= r^3 or CubedRoot(mass) aprox= r)

But, the Schwarzschild radius of this ball is DIRECTLY proportional to its mass. (mass aprox= r)

So, there comes a point, when the ball of water is massive enough, that it's "normal" radius will be LESS than the Schwarzschild radius.

Question:

What does it look like to the various observers, while we add sufficient water to take it under the Schwarzschild radius?

For an outside observer, do the stars that shine through the water ball: fade away as we approach the critical mass, "slide" towards the edge, just "snap off" when we reach it, or some combination?

What about for an observer scuba-diving a few meters beneath the surface that is looking towards the center, and one looking towards the surface?

p.s.

If this particular use of magic renders the entire thought experiment useless, perhaps you see what I'm looking to visualize and can suggest a better way to express the scenario. ( I was initially thinking neutronium would be better than water since it's less compressible and won't undergo fusion, but I assume it's NOT transparent. Also, scuba diving in it would be difficult, at best.)