AS102 Study Guide - Midterm Guide: Spiral Galaxy
Document Summary
As your textbook states, shapley plotted the direction and distance to the globular clusters and found that they form a great swarm that is not centred on the sun. The sun was not at the centre of the galaxy and the centre of the galaxy was thousands of light-years in the direction of the constellation sagittarius. Soon, other astronomers used shapley"s work to realize that some of the light smudges seen through the better telescopes of the day might just be other galaxies and this is where edwin hubble"s work enters the picture. We now know that our galaxy is known as a spiral galaxy, one of the three main types of galaxies, because of the spiral arms trailing off from the central bulge. Pictures of it are shown near this commentary. Of course, these images are not actual photographs of the milky way as no one has ventured outside our.
