School physics has always taught us that the big difference between a magnetised object and an electrostatically charged object is that the latter has on it an isolated positive or negative charge whereas the former cannot be an isolated N or S pole, ie. you cannot have a magnetic monopole on a macroscopic level. I have been bothered by that way of thinking because of the following thought experiment. An astronaut lands on a small planet whose outer mantle had been blown off so that it is nothing but a smooth cooled down nickel-iron core. He then places a large ordinary bar magnet upright on the surface with its N pole at the top. For all intents and purposes he now has an isolated N pole because the S pole has “vanished” and he can slide his monopole over the surface of the planet until he decides to lift it up. How is this different in principle from our having on Earth an isolated negative charge at the end of a dry amber rod? Of course the rod can be moved about in a vacuum chamber and its isolated charge maintained until it touches a conductor whereas that monopole always has to have its conducting bar in contact with that “ferroplanet”, but that difference is just a matter of their respective magnetic or electrostatic domains is it not?