dipolar hypothesis

dipolar hypothesis, theory that the Earth’s magnetic field is produced or is best represented by a magnetic dipole, a body having poles of opposite sign, that is, positive and negative. In the first quantitative study made of the Earth’s magnetic field, William Gilbert observed that it resembled the magnetic field of a uniformly magnetized sphere. This field is the same as that of a magnetic dipole, and early theories of the origin of the geomagnetic...