Magnetic fields that permeate the interstellar medium (ISM) play an important role in various astrophysical processes, such as star formation. Unfortunately, magnetic fields are difficult to detect directly, as they have no effect on neutral photons—the light by which we view the Universe. Magnetic fields do affect the vast clouds of dust in our Galaxy by aligning the dust grains, resulting in the light they emit also being aligned, or polarized. By measuring the polarization of the dust’s emission, we can infer the structure of the interstellar magnetic field over the sky.