Have you ever wondered how it is that we know all we do about galaxies? How they formed, what they're made of, how we can be certain they contain dark matter, and how they grew up in the context of the expanding Universe? In any scientific discipline, we have the things we know and can be quite confident in, the things that we think we've figured out but more data is required to be certain, and the things that remain undecided given the current evidence: things over the horizon of the present frontiers.

Fortunately, we have the ability to scrupulously identify which aspects of galaxy formation and evolution fall into each category, and to walk right up to the edge of our knowledge and peer over that ever-expanding horizon. Joining me for this episode of the Starts With A Bang podcast is scientist Arianna Long, Ph.D. candidate at the University of California at Irvine and soon-to-be Hubble Fellow at the University of Texas at Austin. With the advent of ALMA and the James Webb Space Telescope, in particular, we're poised to seriously push back the frontiers of the unknown, and you can get the insider's view of exactly what we'll be looking for and how. This is one episode you certainly won't want to miss!

Image: This view of a portion of the DREaM simulated galaxy catalog provides a snippet of sky that might correspond, statistically, with what James Webb expects to see. This particular snippet showcases an incredibly rich region of relative nearby galaxies clustered together, which could provide Webb with an unprecedented view of galaxies magnified by strong and weak gravitational lensing. (Credit: Nicole Drakos, Bruno Villasenor, Brant Robertson, Ryan Hausen, Mark Dickinson, Henry Ferguson, Steven Furlanetto, Jenny Greene, Piero Madau, Alice Shapley, Daniel Stark, Risa Wechsler)