eldavojohn writes: Using radio telescope data, scientists from around the world have plotted the Milky Way Galaxy's magnetic field in the form of Faraday Depth. From the article, 'For 150 years, scientists have measured cosmic magnetic field by observing the Faraday effect. They know that when polarized light passes though a magnetized medium, the plane of polarization turns. This concept is called Faraday rotation. The strength and direction of the magnetic field governs the amount of rotation that occurs. So scientists observe the rotation to investigate the magnetic fields' properties. Radio astronomers study the polarized light from distant radio source, passing through the Milky Way on the way to Earth, in order to measure our Galaxy's magnetic field. By measuring the polarization of the light sources at different frequencies, researchers can determine the amount of Faraday rotation.' In the future, radio telescope technologies like LOFAR, eVLA, ASKAP, MeerKAT and the SKA hope to provide enhanced Faraday rotation data so scientists can better understand turbulence in galactic gas and these galactic magnetic field structures.