Our Milky Way is surrounded by dozens of tiny satellite galaxies. These ultra-faint "dwarf" galaxies are the most ancient, most chemically pristine, and most dark-matter-dominated stellar systems known. Observations of these extreme galaxies provide a unique opportunity to better understand galaxy formation, the particle nature of dark matter, and the standard cold dark matter model of cosmology. As telescopes grow larger and more powerful, we continue to find fainter, more distant, and more dark-matter-dominated galaxies inhabiting our “cosmic backyard”. I will describe recent advances in the search for our smallest galactic neighbors and how these observations can help answer some of the biggest questions in cosmology.
