The photon answered one question: the electromagnetic push between charged particles is carried by exchanged photons. But the electromagnetic force is only one of the four fundamental forces. How do the others cross empty space?
The exchange idea is not special to the electromagnetic force. It is a pattern. Start from what you know: charged particles exert the electromagnetic force by exchanging photons.
Charged particles exert the electromagnetic force by exchanging photons.
The strong force follows the same pattern. Particles exert it by exchanging a particle of its own.
The strong force follows the same pattern: its own exchanged particle.
The weak force follows the pattern too. Particles exert it by exchanging particles of its own. So three forces are each exerted the same way: the electromagnetic, the strong, and the weak. The particles involved exchange a particle.
Three forces, one pattern: an exchanged particle carries each force.
An exchange particle that carries a force is called a force-carrier boson. The photon is the force-carrier boson of the electromagnetic force.
What about gravity, the fourth force? Hold that question. A later lesson in this topic answers it.
A friend asks how the strong force gets from one particle to another. What is the answer?
The strong force follows the exchange pattern.
An exchange particle that carries a force is a force-carrier boson.
The particles exchange a particle. A force-carrier boson carries the strong force between them.
Check what you know
How do particles exert the weak force on one another?
The photon is the exchange particle of which force?
What do we call an exchange particle that carries a force?
Which three forces do particles exert by exchanging force-carrier bosons?
Two matter particles exert the weak force on each other. What passes between them?
Which statement about force-carrier bosons is correct?