The standard model of particle physics consists of particles of matter interacting via three fundamental forces: the strong force that holds atomic nuclei together, the weak force that describes (radioactive) beta decay, and the electromagnetic force that we observe in everyday life, for example as electricity.
Well-founded theories assume that these forces were combined into one in the still young and very hot universe. These theories predict the existence of magnetic monopoles, i.e. magnets that only have one south or one north pole. However, these monopoles would exist in such excess that the universe as we observe it could not exist at all. How can this connection be explained and why have these magnetic monopoles not yet been discovered?
Maximilian Bachmaier from the Max Planck Institute for Physics and LMU explains the magnetic monopole problem - and presents a possible solution.