I think I see what you mean.
Take for example Hawkings' theory of black holes, which has been disproven. If your theory is right and the strong force (or some other force) act at the atomic level to increase the density of matter then you would surely see an increase in gravity even to the point that light can't escape.
the problem: if a smaller object was to be tweaked to produce this attraction, the attraction to the earth by an orbiting starship would be the same for the starship orbiting earth, which means that the earth would be greatly affected by the ship.
That's not a problem. For example a handful of the sun would weigh about 1 1/2 times it's own weight on earth.
the other problem: if the strong force was to increase in atoms the atoms would loose structure and implode.
Why?
it explains why gravity is attraction by density, and not size. because a larger object can have less gravity than a smaller object that is more dense. the more dense object has more collective sharing of the strong force.
Gravity is related to mass. An object that's ten times as big as another object with the same mass, has the same gravitational attraction.
There does seem to be very dense spots in our galaxy.