Well forces act on particles and determine their properties. Position is one property. In the case of nuclei and electrons, the forces are electrostatic, which constrain position, momentum, and so on. In the case of planets, the forces are gravitational. I (a particle) am within the gravitational field of the Andromeda galaxy, and so those stars affect my position, velocity, and so on. As it happens, I'm sitting in a much stronger local field, imposed by our earth, which sits within an even stronger field (that of our sun), so Andromeda's grav fields are inconsequential to me. But if I and Andromeda were the only things that existed, I would be pulled toward it, despite how far away it is, because the field does extend to infinity. This is only if you ignore all the other stuff in the universe, of course