CAS CC 111 Lecture Notes - Lecture 1: Henrietta Swan Leavitt, Edwin Hubble, Blueshift

• School: Boston University
• Department: Core Curriculum
• Course: CAS CC 111
• Professor: Andrew Kurtz

Document Summary

Lecture 1 -on the origin of the cosmos - 9/8/16. The universe - the sum total of all matter and energy. The observable universe - the portion of the universe that we can study from earth. 1. light travels at a finite speed: c = 3 x 10^8 m/s, when you view something far away, you are witnessing how it looked in the past c. Light from distant galaxies hasn"t had enough time to reach us. Galaxies are billions of years old equivalently, they are billions of light years away. 1 light year = 9. 46 x 10^15 meters. Nearest stars are 4. 367 light years away (alpha centauri a, b, and proxima centauri. Discovered that variable stars (stars that change in brightness) could be used to determine distance o o o. Periodically changes, stars expands and cools, and shrinks and gets hotter.