This week we conclude our month-long journey through galaxies by exploring one of the biggest questions in astronomy: how galaxies are born, evolve, and eventually die.

We begin in the aftermath of the Big Bang, tracing how tiny fluctuations in matter slowly grew into the first galaxies. Along the way, we explore starburst galaxies, galactic recycling, and the remarkable realization that the elements making up planets, oceans, and even human beings were forged inside ancient generations of stars.

Then we dive into one of the universe’s greatest mysteries: supermassive black holes. Why do most galaxies appear to contain them? Where did these enormous black holes come from? And did galaxies create black holes, or did black holes help create galaxies? We’ll also explore active galactic nuclei, quasars, and the astonishing discovery that  ...