Earth has magnetic fields {magnetic field, Earth} {Earth magnetic field}, because thermal convection from iron-solidification latent heat and escape of inner-core iron oxide and iron sulfide causes liquid-iron outer-core spin {geodynamo}. Magnetic-field strength is 10,000 gauss at Earth surface. Magnetic field is decreasing. Magnetic field reverses polarity randomly, approximately every 250,000 years. Earth magnetic field has had same polarity for last 780,000 years.
Earth has magnetic equator {aclinic line} between magnetic poles.
Ions from Sun can enter Earth atmosphere at poles, along magnetic-field lines. They hit atmosphere atoms and make light displays {aurora, pole}| that look like colored curtains, at North Pole {aurora borealis} {northern lights} or South Pole {aurora australis}.
Earth has magnetic poles {magnetic pole, Earth}|. Magnetic North Pole is in north Canada, not at spin North Pole.
From 600 to 40,000 miles above Earth surface, magnetic fields {magnetosphere} {Van Allen radiation belt} deflect weak cosmic rays and absorb ions from Sun. Sun ions push magnetosphere out from Sun.
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0225