The two objects that would experience the greatest gravitational force between them are the Sun and the largest black hole in the observable universe.

Here's why:

* Gravitational force is directly proportional to mass. The Sun is incredibly massive, and black holes are even more massive. The largest known black hole, TON 618, is estimated to have a mass of 66 billion times that of our Sun.

* Gravitational force is inversely proportional to the square of the distance. While the distance between these two objects would be significant, the sheer magnitude of their masses would still result in an enormous gravitational force.

While we can't directly measure the gravitational force between the Sun and TON 618, due to their vast distance, the mathematical relationship between mass, distance, and gravitational force suggests that this pairing would have the strongest gravitational interaction in the observable universe.