Back to today’s briefing

Story perspectives

Earth's Magnetosphere: Powerful Shield with Shifting Poles

1/20/2025

25 3

Summary

Story summary

The Earth’s magnetosphere, a vital shield against solar winds and space weather, was first discovered by Sir James Clark Ross in 1831. This powerful force, stronger than those of Mars and Mercury, is created by liquid metal in the outer core. Remarkably, the magnetic poles shift and flip every 300,000 years, with the last flip occurring 780,000 years ago.

1 of 1

Story summary

The Earth’s magnetosphere, a vital shield against solar winds and space weather, was first discovered by Sir James Clark Ross in 1831. This powerful force, stronger than those of Mars and Mercury, is created by liquid metal in the outer core. Remarkably, the magnetic poles shift and flip every 300,000 years, with the last flip occurring 780,000 years ago.