Can the Blackett Conjecture Directly Account for the Magnetic Fields of Celestial Bodies and Galaxies? And, is a Lab-based Test for the Blackett Conjecture Feasible?

Abstract

According to the Blackett conjecture, any neutral rotating body acquires a magnetic moment proportional to its angular momentum. Using the data on the dipolar magnetic field of Mars, we put a stringent upper limit on the value of the Blackett's constant, the dimensionless constant that relates the magnetic moment to the angular momentum. As a consequence, the Blackett effect cannot directly account for the magnetic fields of celestial bodies and galaxies. We also show that the Blackett effect cannot be tested in a laboratory since the magnetic moment of any rotating lab-scale object would be much smaller than the one produced by the well-known Barnett effect.