Welcome to the first episode of Crash Course Astronomy. Your host for this intergalactic adventure is the Bad Astronomer himself, Phil Plait. We begin with answering a question: "What is astronomy?" Check out the Crash Course Astronomy solar system poster here: -- Chapters: Introduction 00:00 What is Astronomy? 3:00 Who Studies Astronomy? 3:50 Origins of Astronomy 5:27 Astrology vs Astronomy 6:19 Geocentrism 7:51 Revolutions in Astronomy 8:58 Astronomy Today 10:26 Review 11:29 -- PBS Digital Studios: Follow Phil on Twitter: Crash Course is on Patreon! You can support us directly by signing up at Want to find Crash Course elsewhere on the internet? Facebook - Twitter - Instagram - CC Kids: -- Photos: : %27s_magnetic_field#mediaviewer/File: #mediaviewer/File: #mediaviewer/File: #mediaviewer/File: : #mediaviewer/File:3_Solar_Interstellar_Neighborhood_(ELitU).png #mediaviewer/File: : %27s_Location_in_the_Universe_SMALLER_%28JPEG% #mediaviewer/File: #mediaviewer/File: #mediaviewer/File: #mediaviewer/File: #mediaviewer/File: #mediaviewer/File: #mediaviewer/File: #mediaviewer/File:Justus_Sustermans_-_Portrait_of_Galileo_Galilei,