Résumé :
The origin of the observed magnetic fields in galaxies and
intergalactic space presents a profound cosmological mystery.
An overview of possible mechanisms of their generation is presented.
If the large scale magnetic fields were created in the early universe
they could lead to an observable rotation of polarization plane
of cosmic microwave background radiation. This phenomenon is discussed
in detail.
A simple introduction to the physics of the CMB polarization and the
Faraday rotation of the latter in cosmic magnetic fields is presented.
