This question already has an answer here:
If there were two charges placed at a large distance, won't their (say) magnetic fields interact? What if that large distance is something like close to infinity? Even if they experience a feeble force from each other, doesn't that imply that the magnetic field lines are not closed, as the particle could have been placed anywhere around the source charge at any distance?
Would not this generally say that every electrically charged particle in the universe is part of an infinitely large magnetic field?