Why does earth have a magnetic field?

Earth has this solid iron core, and is surrounded by an immense amount of hot molten metallic fluid. This is mostly iron and thus is magnetic and so it moves around like our ocean currents move around on earth.

And when it's moving around, it's able to generate electrical currents which in turn generate a magnetic field. This is currently our best theory on why Earth has a magnetic field. 

However, Earth's magnetic field is incredibly weak. It's about 400 times weaker than the magnets that you stick on your fridge.

Earth's magnetic field has a huge influence on us. For example we use it for navigation through tools such as a compass, some animals such as bees and fish are able to sense Earth's magnetic field. It's also actively protecting us from huge amounts of harmful particles.

Learn more about this with our series “Inner Earth”

From secret worlds to mystical doors, subterranean land appeared in ancient mythology, and legends in all kinds of flavours. But right under our feet lies an incredible force of nature capable of keeping us alive as well as posing existential threats

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