Why does the Earth, as well as other planets and stars, have a magnetic field?
We'll start our series of articles with a look at the force of electromagnetism.
In the first part of this article we explored Landau's theory of phase transitions in materials such as magnets. We now go on to see how this theory formed the basis of the Higgs mechanism, which postulates the existence of the mysterious Higgs boson and explains how the particles that make up our Universe came to have mass.
What happens when magnetic fields get tangled up in knots? This does happen in the Sun's atmosphere and mathematical models predict that once the magnetic field becomes tangled, it must retain some vestige of this complexity for a long time. This enables the storage of vast quantities of energy. In this article I will outline how the notion of magnetic topology helps us to understand the physical situation and draw such conclusions.