China's FAST telescope detects coherent interstellar magnetic field

Using the Five-hundred-meter Aperture Spherical Radio Telescope (FAST), also dubbed as the "China Sky Eye," scientists have obtained accurate magnetic field strength in molecular cloud, a region of the interstellar medium that seems ready to form stars.

Employing the technique of HI Narrow Self Absorption (HINSA), they achieved a clear detection of the Zeeman effect -- the splitting of a spectral line into several components of frequency in the presence of a magnetic field. It is the only direct probe of interstellar magnetic field strength.

The result suggested that such clouds achieve supercritical state, a critical point when they collapse into stars, happened earlier than previously thought based on the standard model.

The study was published in Nature on Thursday.