A compass needle swinging to point north is hinting at something enormous: our entire planet is a giant magnet, wrapped in an invisible field that reaches far out into space. This episode explains where that field comes from, how it quietly protects life from the Sun's constant barrage, why it flips upside down every so often, and what the rocks tell us about its long and restless history.

You'll come away understanding how Earth's molten interior generates the magnetic field, why the field shields us from harmful solar particles, what magnetic pole reversals are, and why the aurora is the visible signature of an unseen battle overhead.

Talking Science is sponsored by Kinsoft. Visit www.kinsoft.com.au

Further reading: NASA – “Earth's Magnetosphere”;  ...