Can you generate a magnetic field remotely?

TWO CENTURIESMRI ago Hans Christian Oersted, a Danish physicist, demonstrated that the motion of an electric charge produces magnetism. This was the first observation of a wide-ranging phenomenon. The charged clouds of particles which float through the cosmos generate vast interstellar magnetic fields as they go. The sloshing of molten metal in Earth’s core produces the planet’s north and south magnetic poles. Even the firing of nerve cells in a human brain creates a minuscule amount of magnetism.The ubiquity of such electrically generated magnetic fields does, though, bring problems ranging from the pragmatic to the esoteric. Doctors looking at scans, for example, have to compensate for background magnetism. Meanwhile, experimentalists conducting precision tests may have to build complex shields to obscure the magnetic effect of something as simple as an electric wire running through the wall of their laboratory.