Institute for Advanced Study / Princeton University Joint Astrophysics Colloquium - Title Updated

The origin of the large-scale magnetic fields of astrophysical objects remains one of the great unsolved problems of theoretical astrophysics. From planets (including exoplanets) to stars and galaxies, astrophysical objects typically are observed to have organised magnetic fields with systematic properties. For example, the eleven-year solar cycle is a remarkable example of spatio-temporal organisation emerging from a turbulent astrophysical system. In this talk I shall show some observations of astrophysical magnetic fields, before briefly reviewing our current understanding, highlighting limitations of our current theories, and the somewhat perplexing role of magnetic helicity conservation. I shall conclude by proposing possible avenues for future research suggested by recent results of dynamos with large-scale shear flows and helicity loss.