A half-million stars blaze in the center of the Milky Way Galaxy in this view from Hubble Space Telescope. Various studies put the distance to the galaxy's hub at 23,000 to 30,000 light-years. A black hole about four million times the mass of the Sun lies at the center, surrounded by vast clouds of stars. [NASA/ESA/Hubble Heritage Team (STScI/AURA)]
Find out more in our radio program entitled In the Middle.