Gravitational forces of a building In trying to understand the gravitational forces of a building, I have devised a thought experiment:
A building is floating in space. The building's mass is asymmetrically distributed. Inside it also has a large concentrated mass, not aligned to the center of gravity of the building as a whole.
We let loose a bunch of dust particles inside the building. Given the gravitational forces of the building's mass, where would these particles be collected?
I have considered a couple of scenarios: A: The dust would float around evenly distributed, because the gravitational forces inside the building cancel each other out.
B: The dust collect around its nearest walls and ceilings, i.e. the local masses inside the system.
C: All particles are attracted towards the center of mass of the building as a whole, i.e. the global center of gravity.
D: The dust moves towards the densest single mass inside the building.
E(mistyped as another C in image below): Something else.

Any answers for the real scenario and its underlying principles would be much appreciated.
A: A is not correct. Gravitational forces inside the building will not cancel out, except in a few specific locations - and even those locations will not be stable equilibrium points.
C is not correct. The concept of centre of mass is only relevant for calculating gravitational forces on objects outside of the building - and even then, only if the building's design is symmetric.
So you are left with a combination of B and D. Dust close to walls an ceilings will be gravitationally attracted to the nearest surface. Dust floating in the centre of a room will be gravitationally attracted towards the large mass concentration.
This is like our solar system. For objects near to or on the surface of a planet, the most significant gravitational attraction acting on them is the planet. For objects in outer space, not close to a planet, the most significant gravitational attraction acting on them is the Sun, which contains more than 99% of the mass in the solar system.
