Thanks to observations of galaxy redshifts, we can tell that the universe is EXPANDING! Knowing that the universe is expanding and how quickly its expanding also allows us to run the clock backwards 14 billion years to the way the universe began - with a bang.

Crash Course Astronomy Poster: store.dftba.com/products/crashcourse-astronomy-poster

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Table of Contents
Distant Galaxies Show a Red Shift in Their Spectra 2:07
The Universe is Expanding 2:51
This Model is Called “The Big Bang” 5:12
The Universe is Almost 14 Billion Years Old 11:43


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PHOTOS/VIDEOS
Hubble Goes to the eXtreme to Assemble Farthest-Ever View of the Universe 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 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 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 Data System]
Andromeda www.nasa.gov/images/content/386910main_M31_optical_wide.jpg [credit: Bill Schoening, Vanessa Harvey/REU program/NOAO/AURA/NSF]
The Big Bang (video) svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10128 [credit: NASA]
The Sun www.nasa.gov/sites/default/files/706436main_20121114-304-193blend_m6-orig_full.jpg [credit: NASA/SDO]
Alpha Centauri www.eso.org/public/images/eso1241e/ [credit: ESO/Digitized Sky Survey 2, Acknowledgement: Davide De Martin]
Andromeda en.wikipedia.org/wiki/Andromeda_Galaxy#/media/File:Andromeda_galaxy_2.jpg [credit: NASA/JPL-Caltech]
Friedmann Universes commons.wikimedia.org/wiki/File:Friedmann_universes.svg
Friedmann Equation burro.astr.cwru.edu/Academics/Astr328/Notes/Expansion/friedmann.html
Penzias and Wilson stand at the 15 meter Holmdel Horn Antenna that brought their most notable discovery. en.wikipedia.org/wiki/Arno_Allan_Penzias#/media/File:Horn_Antenna-in_Holmdel,_New_Jersey.jpeg [credit: NASA]
Planck CMB www.esa.int/spaceinimages/Images/2013/03/Planck_CMB [credit: ESA and the Planck Collaboration]
Galaxy Superclusters irfu.cea.fr/Projets/coast_documents/images_MareNostrum/SDvision-MN00097-hires-01-mymix-a0_075.jpg [credit: Marenostrum Numerical Cosmology Project]

1. Introduction to Astronomy
2. Naked Eye Observations
3. Cycles in the Sky
4. Moon Phases
5. Eclipses
6. Telescopes
7. The Gravity of the Situation
8. Tides
9. Introduction to the Solar System
10. The Sun
11. The Earth
12. The Moon
13. Mercury
14. Venus
15. Mars
16. Jupiter
17. Jupiter's Moons
18. Saturn
19. Uranus & Neptune
20. Asteroids
21. Comets
22. The Oort Cloud
23. Meteors
24. Light
25. Distances
26. Stars
27. Exoplanets
28. Brown Dwarfs
29. Low Mass Stars
30. White Dwarfs & Planetary Nebulae
31. High Mass Stars
32. Neutron Stars
33. Black Holes
34. Binary and Multiple Stars
35. Star Clusters
36. Nebulae
37. The Milky Way
38. Galaxies, part 1
39. Galaxies, part 2
40. Gamma-Ray Bursts
41. Dark Matter
42. The Big Bang, Cosmology part 1
43. Dark Energy, Cosmology part 2
44. A Brief History of the Universe
45. Deep Time
46. Everything, The Universe...And Life
47. Explore The Solar System:

In this Crash Course series, marvel at the wonders of astronomy with your host for this intergalactic adventure, the Bad Astronomer himself -- Phil Plait. In just 40 short lessons, you will learn the basics of the oldest science known to humanity.

Be sure to check out links to relevant Photos in the description for each video.