Galactic Structures: Where do they come from? Where do they go?

Our observations of galaxies, from nearby to the edges of the observable universe, reveal striking diversity of size, environment, composition, and apparent structure. Ranging from the clumpy irregulars, through the massive round ellipticals, to the coherent disks — probing the mechanisms responsible for these formations in nature requires a wide range of investigative tools from theoretical observations to detailed spectroscopic observations. Barred spirals comprise 50% of the observed population of nearby disk galaxies yet the physical mechanisms that create and sustain these features are not well understood despite persistent study for nearly 200 years...