When Earth Lost 90% of Its Magnetic Field

About 42,000 years ago, Earth’s magnetic field temporarily collapsed in a dramatic episode scientists call the Laschamps Excursion. During this event, the magnetic strength dropped to around ten percent of its normal level, leaving the planet exposed to intense cosmic and solar radiation. The skies would have glowed with widespread auroras, while increased radiation may have damaged the ozone layer and destabilized global climate patterns. Paleoclimate evidence suggests this magnetic crisis coincided with major environmental upheavals — shifting wind belts, cooler temperatures in some regions, and expanding ice. It also overlaps with key turning points in human prehistory, including the disappearance of the Neanderthals and cultural changes among early Homo sapiens. Though direct causation remains debated, the Laschamps Excursion marks a moment when the planet’s protective shield nearly failed. This rare collapse of Earth’s magnetic field serves as a reminder of how deeply life depends on invisible forces. For a brief time, our world was exposed to the raw energy of space — and yet, humanity endured. #Prehistory #MagneticField #LaschampsExcursion #Neanderthals #Paleoclimate #EarthScience #humanevolution 00:00 Intro 00:52 The Geodynamo Falters 03:08 Bombardment From Space 05:15 The UV Problem 08:14 An Ice Age Gets Worse 10:24 Extinction Pulse 13:48 Modern Humans Take Shelter 17:26 The Kauri Tree Archive 19:25 It Could Happen Again