The Big Bang, Cosmology part 1: Crash Course Astronomy #42

Thanks to observations of galaxy redshifts, we can tell that the universe is EXPANDING! Knowing that the universe is expanding and how quickly it's expanding also allows us to run the clock backward 14 billion years to the way the universe began - with a bang. Check out the Crash Course Astronomy solar system poster here: http://store.dftba.com/products/crashcourse-astronomy-poster If you want to learn more about the creation and death of the universe, watch Crash Course Big History here: https://youtube.com/playlist?list=PL8dPuuaLjXtMczXZUmjb3mZSU1Roxnrey -- Chapters: Introduction: The Origins of the Universe 00:00 Distant Galaxies Show a Redshift in Their Spectra 2:07 The Universe is Expanding 4:13 The Big Bang 5:12 Lookback Time 6:06 The Cosmic Microwave Background 7:50 What is the Universe Expanding Into? 9:17 Review 12:12 -- PBS Digital Studios: http://youtube.com/pbsdigitalstudios Follow Phil on Twitter: https://twitter.com/badastronomer Want to find Crash Course elsewhere on the internet? Facebook - http://www.facebook.com/YouTubeCrashCourse Twitter - http://www.twitter.com/TheCrashCourse Tumblr - http://thecrashcourse.tumblr.com Support CrashCourse on Patreon: http://www.patreon.com/crashcourse -- PHOTOS/VIDEOS Hubble Goes to the eXtreme to Assemble Farthest-Ever View of the Universe http://www.nasa.gov/mission_pages/hubble/science/xdf.html [credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team] Out of this whirl: The Whirlpool Galaxy (M51) and companion galaxy http://www.spacetelescope.org/images/heic0506a/ [credit: NASA, ESA, S. Beckwith (STScI), and The Hubble Heritage Team STScI/AURA)] Red-Shifts in the Spectra of Extra-glactic Nebuale http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1936ApJ....83...10H&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf [credit: American Astronomical Society, NASA Astrophysics D