Can a particle affect another at a great distance?

Answer 1

It is possible for one particle to affect another at a great distance, but as a matter of practicle application, the force (or forces) acting between them probably won't have much of an effect. Let's look at a couple of examples.

If two particles are examined, we'll note that each has some gravity associated with it. Gravity will allow the two particles to "pull" on one another. But at a distance, this force will be extremely small. It will not be zero, but it may have little effect. If the two particles are neutrons that are out in deep space, someone who applies some thought and uses a good calculator can demonstrate that the two neutrons attract each other. Even over a distance of miles, the force acting between them will be a non-zero one. They pull on each other. But if the particles have any inertia at all, which is to say that if they are moving relative to each other, only if they are moving ateach other will they have a chance of "meeting" at some point. Should they be moving "away" from each other, gravity acting between them won't stand a chance of allowing them to "hook up" at some point.

If we consider a pair of particles that have an associated electrostatic charge, these particles will have gravity (proportionate to mass), but will also possess an electric field about them. This field will cause particles with a like charge to be pushed away, and will cause those with an opposite charge to be attracted. Additionally, the force will (like gravity) be proportional to the inverse square of the distance over which it is operating. Though the charged particles have an associated gravimetric field about them (as all things that have mass do), we will find that gravity is a "small" force when compared with the electrostatic forces at work. Again, if a pair of charged particles is in deep space, each will "know" the other is there. And each will act on the other in either an attracting or repulsing way. But we again note that if the distance between the particles is extremely great compared to the force acting between them.

If the particles we are examining have the same charge, the particles will push on each other. If the charges are opposite, the particles will attract each other. But we again encounter the idea that if the particles are not actually moving toward each other to begin with, oppositely charged particles will have almost no chance of "meeting" each other. And if the charges are alike, the particles will continue to move apart with little change because of the affects of the charge of the other particle. Again we can calculate the force(s) acting between the particles, and we'll see that they are not zero. But they will be miniscule at best, and will not really affect the two particles greatly. If we consider the effect between two particles miles apart in a place like earth, there are almost countless atoms in between the two particles, and each particle will be "reacting" to what is happening in his own "neighborhood" and will not be affected by the "cross town" goings on.

Answer 2

Yes, particles can affect each other at great distances through fundamental forces like gravity, electromagnetic force, and the nuclear forces. This is known as action at a distance and is a key concept in physics.