Mapping the entirety of our home galaxy is “the most Important thing in astrophysics –Optically, it’s like trying to look through a velvet cloth—black as black can be. In terms of tracing and understanding the spiral structure, essentially half of the Milky Way is terra incognita,” says Thomas Dame, Director of the Radio Telescope Data Center at the Harvard-Smithsonian Center for Astrophysics and Senior Radio Astronomer at the Smithsonian Astrophysical Observatory.