Gravity Humans think that gravity is a simple, singular force, but gravity has many aspects and varies depending on the composition of the objects in question and their distance from each other.
Gravity differs between objects of different compositions.
Like compositions attract each other more, due to the compatibility of their makeup. They have no extraneous dramas to resolve. Metals figure heavily in this, no pun intended, as a magnetic component enters into the equation. Where there is flexibility for the objects to turn, one or both will maneuver such that they are magnetically aligned. This takes time, however slight, and thus an iron ball may appear to fall more slowly in a vacuum than an object of comparable weight that has but a slight magnetic retention.