In this illustrated talk, Dr. Burgasser explains what happens when a newly forming star doesn't have "what it takes" to produce energy in its core in an ongoing way.  This results in "failed stars" or brown dwarfs -- objects that were predicted in theory, but only discovered in the 1990's.   Today, many thousands of these brown dwarfs are known, spanning a wide range of temperatures and masses, and occupying a unique niche at the intersection of stars and planets. Dr. Burgasser discusses how such faint objects are discovered, highlights their exceptional properties, and describes what this (mostly) invisible population can tell us about the formation and history of our Milky Way Galaxy.   Recorded March 9, 2022.Adam Burgasser is a professor of Physics at the University of California,  San Diego, and an astrophysicist who studies the coldest stars, brown dwarfs, and extrasolar planets. Prof. Burgasser defined the “T spectral class” of brown dwarfs as a graduate student; and is one of the co-discoverers of the TRAPPIST-1 exoplanetary system, a system of seven Earth-sized planets orbiting an object at boundary of the star/brown dwarf divide.