Transcript: The night sky blazes with light. Far from a city you can see six thousand stars, and long before the invention of the telescope people could plainly see a band of diffuse light that arches across the sky. Twenty-five hundred years ago Democritus, the Greek philosopher, attributed this glow to unresolved stars. It was called the Via Lactea or the Milky Way. Soon after the invention of the telescope Galileo confirmed Democritus’ idea and showed that the diffuse light is in fact comprised of the pinpoint light of many distant stars. A galaxy is a large collection of stars held together by gravity. The Milky Way galaxy contains the Sun, all the stars in the night sky, and billions more beyond.