A team of scientists led by the Max Planck Institute for Astrophysics (MPA) has produced the highest resolution map of the Milky Way's magnetic field by using more than 41,000 measurements from 26 projects, as reported in Gizmag.com.
Each of the map’s 41,330 individual data points represents a Faraday depth measurement, which is a value of magnetic field strength along a particular line of sight. “Polarized light from radio sources in space is observed for the Faraday effect, which describes the rotation of the plane of polarization,” Gixmag.com reported. “The degree and direction of rotation are determined, and from this the magnetic field strength in a given direction is established.”
Above is a view of the Milky Way by Bala Sivakumar from our point of view; below is the actual map, whose red areas indicate the parts of sky where the magnetic field points toward the observer and blue areas indicate parts of sky where the magnetic field points away from the observer.