Center of the galaxy

A century ago, astronomers observed that almost all star clusters were found in one hemisphere of the sky. Using the Cepheid yardstick and the latest telescope, a three-dimensional model of the Milky Way's globular clusters was created, revealing their spherical arrangement around Sagittarius. We now know that we are about 30,000 ly from the center of the galaxy, and that it is 100,000 ly across.
 Harlow Shapley United States 1918 Center of the galaxy

A century ago, astronomers observed that almost all star clusters were found in one hemisphere of the sky. Using the Cepheid yardstick and the latest telescope, a three-dimensional model of the Milky Way's globular clusters was created, revealing their spherical arrangement around Sagittarius. We now know that we are about 30,000 ly from the center of the galaxy, and that it is 100,000 ly across.