AST 104 Lecture Notes - Lecture 16: Harlow Shapley, Caroline Herschel, Red Giant
Document Summary
Lecture 16: structure of the milky way part 1. Galileo (around 1610) telescopic view revealed that the milky way contains a huge number of faint stars. Thomas wright (1750) a 3d explanation for a band of faint stars. William & caroline herschel (brother and sister) (1784) Attempt to explain the dark gap of stars. Remember, there is more than just visible light more than just what our eyes can see. There are giant clouds of dusty gas between the stars, obscuring much of our view along the plane of the milky way. These clouds are opaque to visible light but transparent to longer wavelengths (infrared). Can contain hundreds to a few thousand stars. Typically have many blue main-sequence stars (o, b, a types) Open clusters are spread along the milky way. Can contain more than a million stars. Always lack blue stars along their main sequences. Feature many yellow stars along their main sequences.
