Cosmic Journeys: Supermassive Black Hole in the Milky Way Galaxy (2009)
From a distance, our galaxy would look like a flat spiral, some 100,000 light years across, with pockets of gas, clouds of dust, and about 400 billion stars rotating around the galaxy's center. Thick dust and blinding starlight have long obscured our vision into the mysterious inner regions of the galactic center. And yet, the clues have been piling up, that something important, something strange is going on in there. Astronomers tracking stars in the center of the galaxy have found the best proof to date that black holes exist. Now, they are shooting for the first direct image of a black hole.