Empirical Earth · Flight & Navigation
Magnetism, monopoles & the poles
The claim
“A compass always points north, so there’s one magnetic monopole at the disc’s center.”
What is measured
A compass needle dips toward the ground at an angle that climbs from 0° at the magnetic equator to 90° at the poles. That is Earth’s dipole, charted for centuries.
What would show this is wrong
a compass dip angle that did not vary with magnetic latitude as a dipole field requires.
Sources
- Magnetic monopoles & Maxwell's equations. ∇·B = 0 (Gauss's law for magnetism); no isolated magnetic charge has ever been observed (e.g., MoEDAL searches at the LHC). Standard E&M (Griffiths, link
- Geomagnetism & the World Magnetic Model 2025. NOAA NCEI & British Geological Survey — geographic / magnetic-dip / geomagnetic poles, inclination, declination, secular drift toward Siberia. n link
- The South Atlantic Anomaly and the offset geomagnetic dipole. Earth’s magnetic dipole is tilted ~11° from the rotation axis and offset ~500 km from the geographic center, producing a region link
- Earth’s magnetosphere. The solar wind compresses Earth’s magnetic field into a cavity: a bow shock near 15 Earth radii, a dayside magnetopause near 10 Earth radii, and a magnetotail stretchi link
- The geodynamo, not a bar magnet. Iron loses its magnetism above its Curie point near 770 °C, and Earth’s core is far hotter, so the field is not a permanent magnet; it is generated by the co link
The full entry, with the working →