Help us continue exploring the greatest questions of the universe with a tax-deductible donation to Closer To Truth: https://shorturl.at/OnyRq   Astrophysicist Or Graur offers a brief and fascinating overview of the history, physics, and astrophysical uses of galaxies. Starting with the history of the last two thousand years of galaxy studies, Graur discusses the types of galaxies we observe and the physics that drive them; the myths and physical structure of the Milky Way; how galaxies were used to discover and study the mysterious phenomena of dark matter and dark energy; and how scientists think galaxies formed shortly after the Big Bang and evolved to their present forms.   Watch more Closer To Truth Chats: https://t.ly/jJI7e   Or Graur is Associate Professor of Astrophysics at the University of Portsmouth's Institute of Cosmology and Gravitation, as well as Research Associate at the American Museum of Natural History. He is the author of "Supernova" and his latest book, "Galaxies" from MIT Press.