The FAA announced that the poles have shifted significantly
over the past year. Runways that were surveyed with compass initially are now pointing in the wrong direction more than slightly. Now that GPS is ubiquitous, runway 15/33 might be 13/31! Edmond Halley
, second Astronomer Royal, was in his time best known for charting loci of constant magnetic field (isogonic lines) worldwide. His charts were used for more than a century, particularly until precise timepieces proliferated for determining longitude. Because the Earth’s magnetic field is changing continually (mainly because of the mobility of the Earth’s core), the isogonic charts were augmented with periodic surveys and mariners’ observations. No one could confirm the return of Halley’s Comet until he was dead! Perhaps the FAA should have used Halley’s charts?