To learn more about Earth's magnetic field, the three Swarm satellites were launched on 22 November. Like 3D compasses, they are measuring the strength and direction of the magnetic field.<br /><br />This is the third of three videos:<br />Magnetic field: an introduction: http://www.youtube.com/watch?v=P7nhgX0ppek<br />Magnetic field: why it matters: http://youtu.be/6vYzVdSxjUs <br />Magnetic field: learning more with Swarm<br /><br />More about Swarm: www.esa.int/swarm
