AS102 Study Guide - Final Guide: Hipparcos
Document Summary
The origin and history of the milky way galaxy. These are big questions and yet, astronomers have studied the properties of the galaxy and we believe we have some pretty good answers. First, let"s consider the age of the galaxy. This is different from the age of our solar system. In as101 you learned that our star and solar system (including earth) is about. You may also have learned that we believe our universe is about 14 billion years old. So, our galaxy must be somewhere between 5 billion and 14 billion years old. More recent data from the hipparcos satellite has refined this figure to possibly as much as 13 billion years. This means that our galaxy is probably one of the oldest galaxies and formed within a few billion years of the big bang the start of it all! Astronomers have divided the stars making up the galaxy into two types; population i and population ii stars.
