The magnetic field

There is strong evidence that the Milky Way galaxy contains an ordered, large-scale magnetic field of the value of some $micro gauss$ $(\mu G)$. This field configuration has been explored through various methods which include analysis of starlight polarization, modeling pulsar or Faraday rotation, and Zeeman splitting of hydroxyl masers in regions of star formations. The galactic magnetic field can gradually act on the dust particles and cause their rotational axes to line up, therefore their axes are parallel to the direction of the field which is in turn aligned with the Milky Way band and the galactic plane. This pattern is confirmed by polarization measurements. The Zeeman splitting of atomic or molecular lines is used to determine the direction and magnitude of a component of the magnetic field in the diffuse and molecular clouds.