Cosmology Lecture 2 - YouTube

https://www.youtube.com/watch?v=938_TNP4aUs&t=25s&list=PLvh0vlLitZ7c8Avsn6gUaWX05uD5cedO-&index=2

Help us caption and translate this video on Amara.org: http://www.amara.org/en/v/BWxT/ (September 21, 2013) Leonard Susskind solves the expansion equation fo...