Galactic dust grains are aggregations of molecules in the interstellar medium, which form preferentially at denser locations. Dust plays a central role in galactic physics, it obscures the view on stars by its optical light absorption and obfuscates our view on the cosmic microwave background by its emission of the absorbed energy at longer wavelength. The structure of dust clouds as well as their polarized emission reveals the orientation of galactic magnetic field lines.
Thus, knowing the 3D dust distribution in the Milky Way is of paramount importance for a number of scientific questions, ranging from understanding ISM chemical processes like the formation of proto-biological molecules, over star formation, Galactic magnetism, to cosmology. In this talk, I will present the most recent 3D Galactic dust tomography results and highlight some of their scientific implications.