The Magnetic Field in Milky Way “Bones”

The dark filament “Nessie,” as seen in the infrared with the IRAC camera on Spitzer. Nessie, a cloud of cold gas and dust, is a “bone” tracing the Milky Way’s spiral arm structure. Astronomers have used SOFIA, NASA’s Stratospheric Observatory for Infrared Astronomy, to measure the magnetic field along the bone G47.06+0.26 via its infrared polarization. Credit: NASA/JPL/SSC