Remember that amazing high-def photo of M31, the Andromeda Galaxy, from Hubble a few months back? It was able to separate the light from the galaxy into the millions of visible stars that populate its spiral arms.  This image is used for far more than the wow factor of seeing another galaxy up close.  It allows us to study the entire galaxy and gain insights into the lives of spiral galaxies beyond our own, how they formed, how they evolve, and maybe even how they will eventually die. By looking at the spiral arms of M31, where the youngest and...