Galaxies and their Masks

Various kinds of masks obscure our view of our galaxy, the Milky Way, as well as of other galaxies. Masks of interstellar dust affect our measurements within galaxies, on scales ranging from individual supernovae to the galaxies themselves. The "mass mask" (our inability to image mass rather than light) gives astronomers a very incomplete picture of the size and structure of galaxies themselves, because we cannot image the dark matter which provides most of the galactic mass. Another mass is the "dynamical mask": as galaxies form, much dynamical information is lost in the birthing process.