The Milky Way Galaxy


Look up at night -- not from Cleveland (or any other city for that matter). We see a faint band of light overhead: the Milky Way

Using a telescope, the Milky Way can be resolved into individual stars.

(Milky Way from KPNO)

Let's "unwrap" the sky and make a map. What do we see?

From Axel Mellinger's Milky Way Panorama page. There's a newer, beautifully interactive version as well.
1755: Immanuel Kant proposes that the Galaxy is a disk of stars (including our Sun)

1785: Wiliam Herschel uses star count data to map the Milky Way. He assumes:

  • all stars have the same brightness
  • the galaxy has a uniform density
  • he can see to the edge
Herschel's map of the Milky Way puts the Sun very near the center of the Galaxy.
Herschel's map of the Milky Way