AY 101 Chapter Notes - Chapter 1: Local Group, Observable Universe, Cosmic Calendar
15 Jul 2016
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Document Summary
In this rst chapter, we developed a broad overview of our place in the universe. The milky way galaxy, in turn, is one of billions of galaxies in our observable universe: cosmic distances are literally astronomical, but we can put them in perspective with the aid of scale models and other scaling techniques. Stellar deaths released these atoms into space, where our galaxy recycled them into new stars and planets. Our solar system formed from such recycled matter some 4 and a half billion years ago: we are latecomers on the scale of cosmic time. Although we cannot feel this motion, the associated speeds are surprisingly high. Learning about the motions of spaceship earth gives us a new perspective on the cosmos and helps us understand its nature and history. What is our place in the universe: earth is a planet orbiting the sun. Our sun is one of more than 100 billion stars in the milky way.
