Transcript:

So today, we look at why the Earth even has a magnetic field. There's three things needed for any planet to have a magnetic field.

The first is that the planet should be rotating fast enough. The second is that there should be a liquid molten metal layer that is capable of conducting electricity. And the third is that the innermost core should be hot enough to induce convection currents in this liquid molten layer that is sitting below the crust of the planet.

Now, Earth has all these three going for it. It is rotating fast enough. The liquid molten layer below the crust of the Earth is made up of iron and nickel. Both of these conduct electricity. The innermost core is hot enough to induce movement of these iron and nickel particles.

Now remember, from basic physics — if the thumb points in the direction of positive current, the fingers, the right-hand rule, the fingers give the direction of the magnetic field. This is what is happening in the Earth. There is convection current set up in the nickel and the iron layer. And the Earth is rotating. So, these charges are being moved around. And these moving charges generate the magnetic field that is protecting the Earth from the charged particles from the sun.