“What if we've missed something?”
The electric force is 10^36 times greater than gravity. Most humans, including physicists cannot really visualize a number with 36 zeros behind it. Because charges can either attract or repel, the electric forces in the universe ALMOST but not quite in some instances cancel each other. It is the ignoring of this tiny imbalance which is not being accounted for in the motion of the galaxies that causes astrophysicists to suggest the existence of dark matter, dark energy and black holes. None of these strictly mathematical constructs have ever been discovered to actually exist.