Inside The Milky Way embarks on an astounding journey across 100,000 light-years to witness key moments in the history of the Milky Way. Using current science, a spectacular 3-D state-of-the-art CGI model of our galaxy is constructed and intimate interviews with leading scientists combine to offer an in-depth look into the heart of the Milky Way on the hunt for super-massive black holes. Witness as stars are born and die. Fly out and above the plane of our galaxy to understand its true shape and scour its dusty spiral arms for the possibility of life.
The Milky Way is a barred spiral galaxy 100,000–120,000 light-years in diameter containing 200–400 billion stars. The galaxy is estimated to contain at least as many planets, 10 billion of which could be located in the habitable zone of their parent star. Depending on its structure the entire galaxy has a rotational rate of once every 15 to 50 million years. The galaxy is also moving at a velocity of 552 to 630 km per second, depending on the relative frame of reference. It is estimated to be about 13.2 billion years old. The Milky Way is part of the Local Group of galaxies.
The galaxy has this appearance because it is a disk-shaped structure that is being viewed from inside. Earth is located within the galactic plane of this disk, around two thirds of the way out from the center, on the inner edge of a spiral-shaped concentration of gas and dust called the Orion–Cygnus Arm. The concept of this faint band of light being made up of stars was proven in 1610 when Galileo Galilei used his telescope to resolve it into individual stars. In the 1920s observations by astronomer Edwin Hubble showed that the Milky Way was just one of at least 200 billion galaxies in the observable universe.