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?

TL;DR

This paper evaluates the Blackett conjecture's ability to explain celestial magnetic fields and finds it insufficient, also concluding that lab tests are unfeasible due to scale limitations.

Contribution

The study provides new upper limits on Blackett's constant using planetary magnetic data and demonstrates the impracticality of laboratory tests for the conjecture.

Findings

Blackett effect cannot explain magnetic fields of celestial bodies.

Laboratory tests for the Blackett effect are not feasible.

Upper limits on Blackett's constant are established from Mars data.

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.