AS102 Study Guide - Final Guide: List Of Largest Galaxies, Milky Way, Spiral Galaxy
Document Summary
Irregular galaxies tend to be smaller than our galaxy (which is a spiral galaxy), some as little as 1% the size of the milky way and with low luminosity. The milky way galaxy is certainly one of the largest galaxies in both size and luminosity. Some elliptical galaxies are five or more times the diameter of our galaxy. The masses of galaxies are determined by using the rotation curve method (outlined in your textbook). This means that the milky way galaxy is fairly representative of the largest and most luminous galaxies in the universe. However, when we compare the size and luminosity of a given galaxy and imagine, therefore, how much matter it contains and compare that to the mass measurement we calculate we often (usually!) find that things just don"t add up! It turns out that the measured mass is much larger than expected from the size-luminosity determination method.
