ASTRONOMY CRASH COURSE

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?" -- Table of Contents: What is Astronomy? 3:00 Who Studies Astronomy? 3:50 Origins & Developments 6:52 -- 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 Subbable: http://subbable.com/crashcourse -- Photos: http://commons.wikimedia.org/wiki/File:Earth_cutaway.png http://en.wikipedia.org/wiki/Earth%27s_magnetic_field#mediaviewer/File:Geodynamo_Between_Reversals.gif http://en.wikipedia.org/wiki/Geomagnetic_storm#mediaviewer/File:Magnetosphere_rendition.jpg http://en.wikipedia.org/wiki/Saturn#mediaviewer/File:Saturn_PIA06077.jpg http://en.wikipedia.org/wiki/243_Ida#mediaviewer/File:243_Ida_large.jpg http://commons.wikimedia.org/wiki/File:Comet_Hale_Bopp_NASA.jpg http://solarviews.com/raw/comet/kuiper3.jpg http://solarviews.com/cap/comet/kuiper3.htm http://en.wikipedia.org/wiki/List_of_nearest_bright_stars#mediaviewer/File:3_Solar_Interstellar_Neighborhood_(ELitU).png http://www.slate.com/blogs/bad_astronomy/2013/06/28/planetary_nebula_sh2_68_the_flaming_skull_nebula.html http://www.slate.com/blogs/bad_astronomy/2013/06/06/milky_way_galaxy_two_new_discoveries_about_its_spiral_arms.html http://en.wikipedia.org/wiki/Black_hole#mediaviewer/File:PIA16695-BlackHole-Corona-20130227.jpg http://commons.wikimedia.org/wiki/File:Messier_69_HST.jpg http://www.slate.com/blogs/bad_astronomy/2013/06/25/nearby_galaxies_swift_uv_pictures_of_two_galactic_neighbors.html http://upload.wikimedia.org/wikipedia/commons/0/0f/Earth%27s_Location_in_the_Universe_SMALLER_%28JPEG%29.jpg http://www.slate.com/blogs/bad_astronomy/2013/03/21/age_of_the_universe_planck_results_show_universe_is_13_82_billion_years.html http://www.esa.int/spaceinimages/Images/2007/02/True-colour_image_of_Mars_seen_by_OSIRIS http://en.wikipedia.org/wiki/Andromeda_Galaxy#mediaviewer/File:WISE-_Andromeda.jpg http://en.wikipedia.org/wiki/Triangulum_Galaxy#mediaviewer/File:VST_snaps_a_very_detailed_view_of_the_Triangulum_Galaxy.jpg http://en.wikipedia.org/wiki/Hubble_Space_Telescope#mediaviewer/File:HST-SM4.jpeg http://www.slate.com/blogs/bad_astronomy/2013/12/21/winter_solstice_2013_the_shortest_day_of_the_year.html http://www.slate.com/blogs/bad_astronomy/2012/12/28/full_moon_today_is_the_13th_full_moon_of_2012.html http://en.wikipedia.org/wiki/Nicolaus_Copernicus#mediaviewer/File:Nikolaus_Kopernikus.jpg http://en.wikipedia.org/wiki/Tycho_Brahe#mediaviewer/File:Tycho_Brahe.JPG http://en.wikipedia.org/wiki/Johannes_Kepler#mediaviewer/File:Johannes_Kepler_1610.jpg http://en.wikipedia.org/wiki/Isaac_Newton#mediaviewer/File:GodfreyKneller-IsaacNewton-1689.jpg http://en.wikipedia.org/wiki/Galileo_Galilei#mediaviewer/File:Justus_Sustermans_-_Portrait_of_Galileo_Galilei,_1636.jpg http://www.slate.com/blogs/bad_astronomy/2012/09/25/revealing_the_universe_the_hubble_extreme_deep_field.html

Today on Crash Course Astronomy, Phil invites you to head outside and take a look at all the incredible things you can see with your naked eye. -- Table of Contents: Naked Eye Observations 0:28.4 Constellations 3:09.7 The Color of Stars 2:44.5 View of the Stars 7:25 -- 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 Subbable: http://subbable.com/crashcourse -- PHOTOS http://www.eso.org/public/images/potw1333a/ http://commons.wikimedia.org/wiki/File:3_Solar_Interstellar_Neighborhood_(ELitU).png http://www.spacetelescope.org/images/heic0206j/ http://www.spacetelescope.org/images/heic0720c/ http://upload.wikimedia.org/wikipedia/commons/3/36/Orion_tjt.jpg http://hubblesite.org/newscenter/archive/releases/1996/04 http://en.wikipedia.org/wiki/Delphinus#mediaviewer/File:Delphinus_IAU.svg http://en.wikipedia.org/wiki/Scorpius#mediaviewer/File:Sidney_Hall_-_Urania%27s_Mirror_-_Scorpio.jpg http://en.wikipedia.org/wiki/Category:Pisces_(constellation)#mediaviewer/File:Pisces_constellation_map.png http://en.wikipedia.org/wiki/Alpha_Cancri#mediaviewer/File:Cancer_constellation_map.png http://en.wikipedia.org/wiki/GLOBE_at_Night#mediaviewer/File:Light_pollution_It%27s_not_pretty.jpg http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=7543 http://photojournal.jpl.nasa.gov/catalog/PIA00104 http://www.esa.int/spaceinimages/Images/2007/02/True-colour_image_of_Mars_seen_by_OSIRIS http://photojournal.jpl.nasa.gov/jpeg/PIA04866.jpg http://photojournal.jpl.nasa.gov/catalog/PIA06193 http://commons.wikimedia.org/wiki/File:Star_Trails_over_the_VLT_in_Paranal.jpg http://imgsrc.hubblesite.org/hu/db/images/hs-2006-02-a-print.jpg http://en.wikipedia.org/wiki/Circumpolar_star#mediaviewer/File:Circumpolar_AZ81.jpg

This week we build on our naked eye observations from last week and take a look at the cyclical phenomena that we can see at work in the universe. -- Table of Contents: Naked Eye Observations 0:28.4 Constellations 3:09.7 The Color of Stars 2:44.5 View of the Stars 7:25 -- 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 Subbable: http://subbable.com/crashcourse -- PHOTOS http://en.wikipedia.org/wiki/Right_ascension#mediaviewer/File:Stars_and_ra.png http://en.wikipedia.org/wiki/File:Ecliptic_path.jpg http://commons.wikimedia.org/wiki/File:Sagittarius_Hevelius.jpg http://en.wikipedia.org/wiki/Scorpius#mediaviewer/File:Sidney_Hall_-_Urania%27s_Mirror_-_Scorpio.jpg http://en.wikipedia.org/wiki/Libra_(constellation)#mediaviewer/File:Sidney_Hall_-_Urania%27s_Mirror_-_Libra.jpg http://en.wikipedia.org/wiki/Virgo_(constellation)#mediaviewer/File:Sidney_Hall_-_Urania%27s_Mirror_-_Virgo.jpg http://commons.wikimedia.org/wiki/File:Leo_Hevelius.jpg http://en.wikipedia.org/wiki/Cancer_(constellation)#mediaviewer/File:Sidney_Hall_-_Urania%27s_Mirror_-_Cancer.jpg http://en.wikipedia.org/wiki/Globe#mediaviewer/File:GEO_Globe.jpg http://sailornanny.weebly.com/uploads/1/0/5/0/10509307/4835516_orig.gif http://www.slate.com/content/dam/slate/blogs/bad_astronomy/2013/04/28/earth_elliptical_orbit.jpg.CROP.original-original.jpg http://en.wikipedia.org/wiki/Pole_star#mediaviewer/File:Precession_N.gif

In this episode of Crash Course Astronomy, Phil takes you through the cause and name of the Moon's phases. -- Why the Moon Has Phases 0:36.1 Spheres in Orbit 1:05.4 Name of the Moon Phases 2:25.5 How We See It 7:48.2 -- 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 Subbable: http://subbable.com/crashcourse -- PHOTOS http://en.wikipedia.org/wiki/Moon#mediaviewer/File:FullMoon2010.jpg https://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=1879 http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0505.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0553.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0634.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0706.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0809.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0905.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.1011.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.1145.jpg http://en.wikipedia.org/wiki/Moon#mediaviewer/File:NASA-Apollo8-Dec24-Earthrise.jpg http://global.jaxa.jp/press/2008/04/img/20080411_kaguya_01l.jpg http://global.jaxa.jp/press/2008/04/20080411_kaguya_e.html http://www.esa.int/Our_Activities/Operations/First_view_of_Earth_as_Rosetta_approaches_home http://commons.wikimedia.org/wiki/File:Sachin_Nigam_-_starry_moon_%28by-sa%29.jpg https://www.flickr.com/photos/badastronomy/14397419837/

The big question in the comments last week was, "BUT WHAT ABOUT ECLIPSES?" Today, Phil breaks 'em down for you. This episode is sponsored by Squarespace: http://www.squarespace.com/crashcourse -- As promised, Phil's sun spotting recommendations: Astronomers Without Borders (charitable org): http://store.astronomerswithoutborders.org/index.php?main_page=product_info&cPath=8&products_id=3 Rainbow Symphony glasses (I have these myself): http://www.rainbowsymphony.com/soleclipse.html Wide variety of viewers from Rainbow Symphony: http://www.eclipseglasses2017.com/buy-eclipse-glasses -- Solar Eclips 0:59 Lunar Eclipse 1:03 Moon's Orbit 1:23 Size of the Earth and Moon 8:24 -- 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 Subbable: http://subbable.com/crashcourse -- PHOTOS/VIDEOS http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4158 http://www.nasa.gov/audience/forstudents/k-4/stories/solar-eclipse-diagram/#.VMFSKGTF_Z0 http://en.wikipedia.org/wiki/Eclipse#mediaviewer/File:Geometry_of_a_Total_Solar_Eclipse.svg http://en.wikipedia.org/wiki/Solar_eclipse_of_September_22,_2006#mediaviewer/File:Helder_da_Rocha_-_Partial_solar_eclipse_(by-sa).jpg http://commons.wikimedia.org/wiki/File:Solar_eclipse_2008Feb07-New_Zealand-partial-Greg_Hewgill.jpg http://en.wikipedia.org/wiki/Solar_eclipse#mediaviewer/File:The_Patrial_Eclipse.jpg http://philhart.smugmug.com/Sun/Queensland-Solar-Eclipse/i-qjqMzzK http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11128 http://philhart.smugmug.com/Sun/Queensland-Solar-Eclipse/i-mMSf6gB http://philhart.smugmug.com/Sun/Queensland-Solar-Eclipse/i-LffKLrf https://www.youtube.com/watch?v=7YX2blo1eRk http://en.wikipedia.org/wiki/Solar_eclipse#mediaviewer/File:Annular_Eclipse._Taken_from_Middlegate,_Nevada_on_May_20,_2012.jpg http://commons.wikimedia.org/wiki/File:Geometry_of_a_Lunar_Eclipse.svg http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10787 http://en.wikipedia.org/wiki/File:Lunar_eclipse_April_15_2014_California_Alfredo_Garcia_Jr1.jpg http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10787 http://en.wikipedia.org/wiki/Lunar_eclipse#mediaviewer/File:Lunar_eclipse_oct_8_2014_Minneapolis_4_46am.png http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4155

Today Phil explains how telescopes work and offers up some astronomical shopping advice. -- How Telescopes Work 1:07 Refractors vs Reflectors 2:50 Technology and the Light Spectrum 7:45 -- 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 Subbable: http://subbable.com/crashcourse -- PHOTOS/VIDEOS http://en.wikipedia.org/wiki/Galileo_Galilei#mediaviewer/File:Justus_Sustermans_-_Portrait_of_Galileo_Galilei,_1636.jpg http://en.wikipedia.org/wiki/Human_eye#mediaviewer/File:Human_eye_with_blood_vessels.jpg http://en.wikipedia.org/wiki/Refracting_telescope#mediaviewer/File:Refractor_Cincinnati_observatory.jpg http://commons.wikimedia.org/wiki/File:Positive_lens_2.svg http://www.eso.org/public/images/yb_vlt_moon_cnn_cc/ http://en.wikipedia.org/wiki/Jupiter#mediaviewer/File:Jupiter_MAD.jpg http://en.wikipedia.org/wiki/Wide_Field_and_Planetary_Camera#mediaviewer/File:Hubble_Images_of_M100_Before_and_After_Mirror_Repair_-_GPN-2002-000064.jpg http://commons.wikimedia.org/wiki/File:Prime_focus_telescope.svg http://commons.wikimedia.org/wiki/File:Inspection_of_the_primary_mirror_of_the_Hubble_Space_Telescope8218871.jpg https://www.youtube.com/watch?v=ui6ernRFxOg#t=2m22s http://en.wikipedia.org/wiki/William_Herschel#mediaviewer/File:William_Herschel01.jpg http://commons.wikimedia.org/wiki/File:Grand_Canyon_National_Park,_23_Annual_Star_Party_2013_-_0082_-_Flickr_-_Grand_Canyon_NPS.jpg http://commons.wikimedia.org/wiki/File_talk:EM_spectrum.svg#mediaviewer/File:EM_spectrumrevised.png https://www.youtube.com/watch?v=RqX9vLj3_7w#t=4m52s http://pprc.qmul.ac.uk/~still/wordpress/?page_id=138 http://en.wikipedia.org/wiki/VERITAS#mediaviewer/File:MMT_FLWO_Amado_AZ_10359.jpg http://en.wikipedia.org/wiki/Astrophotography#mediaviewer/File:Henry_Drape_Orion_nebula_1880_inverted.jpg http://en.wikipedia.org/wiki/Astrophotography#mediaviewer/File:Orion-Nebula_A_A_Common.jpg http://en.wikipedia.org/wiki/File:PIA18593-Mars-CometSidingSpring-NEOWISE-20140728.jpg http://en.wikipedia.org/wiki/File:NASA-HS201427a-HubbleUltraDeepField2014-20140603.jpg http://upload.wikimedia.org/wikipedia/commons/2/2b/Jupiter_and_its_shrunken_Great_Red_Spot.jpg http://upload.wikimedia.org/wikipedia/commons/thumb/5/58/Chromatic_aberration_3.svg/2000px-Chromatic_aberration_3.svg.png http://upload.wikimedia.org/wikipedia/commons/5/56/The_Whirlpool_Galaxy_%28M51%29.jpg http://hubblesite.org/newscenter/archive/releases/2005/12/image/a/

In today's episode, Phil looks at how gravity plays out across the universe. This episode is sponsored by Squarespace: http://www.squarespace.com/crashcourse -- Gravity is a Force 2:17 Different Types of Orbit 3:41 Escape Velocity 5:30 Weightless Mass 7:03 -- 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: https://www.patreon.com/crashcourse -- PHOTO/VIDEO CREDITS First photo by Roscosmos / NTSOMZ/ SRC "Planeta" / zelenyikot.livejournal.com http://www.slate.com/blogs/bad_astronomy/2013/09/25/earth_at_equinox_elektro_l_view_of_the_earth_from_space.html http://commons.wikimedia.org/wiki/File:Portrait_of_Robert_Hooke_with_a_book,_spring_and_quill.JPG http://en.wikipedia.org/wiki/Isaac_Newton#mediaviewer/File:GodfreyKneller-IsaacNewton-1689.jpg http://en.wikipedia.org/wiki/Johannes_Kepler#mediaviewer/File:Johannes_Kepler_1610.jpg http://en.wikipedia.org/wiki/Karen_L._Nyberg#mediaviewer/File:Karen_Nyberg_STS124_-_2008June07_(NASA_S124-e007134).jpg https://www.youtube.com/watch?v=doN4t5NKW-k

Today Phil explores the world of tides! What is the relationship between tides and gravity? How do planets and their moons become tidally locked? What would happen if you were 300km tall? Important questions. -- Gravity Over Distance 0:44 Tidal Force Parameters 1:35 Battle of the Bulges 2:55 Tidal Lock 6:17 -- 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 Subbable: http://subbable.com/crashcourse -- PHOTO/VIDEO CREDITS Photo & video credit: "NASA's Scientific Visualization Studio" http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4236 Photo credit: "NASA's Scientific Visualization Studio" https://www.flickr.com/photos/gsfc/8556665115/in/photostream/ http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=1333 The Hopewell Rocks - https://www.youtube.com/watch?v=EnDJ6_XpGfo

In today's Crash Course Astronomy, Phil takes a look at the explosive history of our cosmic backyard. We explore how we went from a giant ball of gas to the system of planets and other celestial objects we have today. This episode is sponsored by Squarespace: http://www.squarespace.com/crashcourse -- Makeup of a Solar System 2:38 From Gas to a Disc 5:36 Planet Formation Depends on Distance to Sun 7:14 Motion of a System 8:21 -- 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 Subbable: http://subbable.com/crashcourse -- PHOTO/VIDEO CREDITS Sun: http://www.nasa.gov/sites/default/files/706436main_20121114-304-193blend_m6-orig_full.jpg [credit: NASA/ESA] Jupiter: http://www.jpl.nasa.gov/images/hubble/20140515/jupiter20140515-full.jpg [credit: NASA/ESA] Geocentric celestial spheres; Peter Apian's Cosmographia (Antwerp, 1539): http://en.wikipedia.org/wiki/Celestial_spheres#mediaviewer/File:Ptolemaicsystem-small.png Ganymede: http://en.wikipedia.org/wiki/File:Noaa_ganymede.jpg Mercury: http://messenger.jhuapl.edu/gallery/sciencePhotos/pics/CW0131775256F_web.png [credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington] Understanding Solar System Dynamics: Orbits and Kepler's Laws (2008): https://archive.org/details/OrbitsAndKeplersLaws Mercury: http://apod.nasa.gov/apod/ap080116.html Venus: http://www.msss.com/all_projects/magellan.php Earth: http://earthobservatory.nasa.gov/IOTD/view.php?id=36019 Mars: http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-mars.html Jupiter: http://www.nasa.gov/mission_pages/cassini/multimedia/pia04866.html Saturn: http://www.slate.com/content/dam/slate/blogs/bad_astronomy/2014/06/Ten%20Years%20at%20Saturn/cassini_ugarkovic_saturn.jpg.CROP.original-original.jpg [credit: Photo by NASA/JPL/Space Science Institute/Gordan Ugarkovic] Uranus: http://hubblesite.org/newscenter/archive/releases/1998/35/image/a/ Neptune: http://www.slate.com/blogs/bad_astronomy/2014/05/15/neptune_voyager_images_updated_for_portrait_of_the_eighth_planet.html http://www.nasa.gov/sites/default/files/hs-2014-29-a-large_web.jpg [credit: JHUAPL/SwRI/Dan Durda] Bennu’s Journey: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=20220&button=recent http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11541 Artist's impression of a protoplanetary disk: http://en.wikipedia.org/wiki/Protoplanetary_disk#mediaviewer/File:Artist%E2%80%99s_Impression_of_a_Baby_Star_Still_Surrounded_by_a_Protoplanetary_Disc.jpg Rocky Ring of Debris Around Vega: http://www.nasa.gov/mission_pages/spitzer/multimedia/pia16610.html [image credit: NASA/JPL-Caltech] Proplyds in the Orion Nebula: http://www.esa.int/Our_Activities/Space_Science/Born_in_beauty_proplyds_in_the_Orion_Nebula

Phil takes us for a closer (eye safe!) look at the two-octillion ton star that rules our solar system. We look at the sun's core, plasma, magnetic fields, sunspots, solar flares, coronal mass ejections, and what all of that means for our planet. This episode is sponsored by Squarespace: http://www.squarespace.com/crashcourse -- The Sun is a Star 1:28 Plasma's Magnetic Fields 6:11 Sunspots, Solar Flares, and Coronal Mass Ejections 7:09 How the Earth Reacts 9:18 -- 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 -- PHOTO/VIDEO CREDITS Hubble extrasolar planet search field in Sagittarius: http://www.spacetelescope.org/images/heic0612d/ [credit: NASA, ESA, K. Sahu (STScI) and the SWEEPS science team] The Sun: http://www.nasa.gov/sites/default/files/images/499558main_hmi4096.jpg [credit: SDO/HMI] The Sun: http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2011/02/SDO_4096_0171.jpg [credit: NASA/SDO/AIA] Earth: http://www.nasa.gov/content/goddard/earth-from-space-15-amazing-things-in-15-years/#.VMvNXmTF_Z0 [credit: NASA's Earth Observatory] Fusion in the Sun: http://commons.wikimedia.org/wiki/File:FusionintheSun.svg [credit: Borb] Empire State Building: http://de.wikipedia.org/wiki/Empire_State_Building#mediaviewer/File:Empire_State_Building_from_the_Top_of_the_Rock.jpg Sun Structure: https://www.flickr.com/photos/[email protected]/2819311727/ Photospheric granulation: http://solarscience.msfc.nasa.gov/images/granules.jpg Corona: http://philhart.smugmug.com/Sun/Queensland-Solar-Eclipse/i-qjqMzzK [credit: Phil Hart] "Magnet0873" by Newton Henry Black - Newton Henry Black, Harvey N. Davis (1913) Practical Physics, The MacMillan Co., USA, p. 242, fig. 200. Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Magnet0873.png#mediaviewer/File:Magnet0873.png Strange Days On The Sun: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11682 [credit: NASA's Goddard Space Flight Center Images courtesy of NASA/SDO] Under the Sunspots: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=20070 [credit: NASA/Goddard Space Flight Center Conceptual Image Lab] Raining Loops: http://svs.gsfc.nasa.gov/vis/a010000/a011100/a011168/Raining_Loops_Still_2.jpg [credit: NASA's Goddard Space Flight Center/SDO] Coronal Mass Ejection: https://www.youtube.com/watch?v=p_xYcMQe5KA [credit: NASA] Aurora: https://www.youtube.com/watch?v=X-BicSV9RAw Soloar Close-ups: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4061 [credit: NASA]

Phil starts the planet-by-planet tour of the solar system right here at home, Earth. -- Table of Contents Earth is a Planet 0:03 Layers of Earth 1:25 The Magnetic Field 5:10 Atmosphere and the Human Influence 6:14 -- 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 Planets: Mercury: http://apod.nasa.gov/apod/ap080116.html Venus: http://www.msss.com/all_projects/magellan.php Earth: http://earthobservatory.nasa.gov/IOTD/view.php?id=36019 Mars: http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-mars.html Jupiter: http://www.nasa.gov/mission_pages/cassini/multimedia/pia04866.html Saturn: http://www.slate.com/content/dam/slate/blogs/bad_astronomy/2014/06/Ten%20Years%20at%20Saturn/cassini_ugarkovic_saturn.jpg.CROP.original-original.jpg [credit: Photo by NASA/JPL/Space Science Institute/Gordan Ugarkovic] Uranus: http://hubblesite.org/newscenter/archive/releases/1998/35/image/a/ Neptune: http://www.slate.com/blogs/bad_astronomy/2014/05/15/neptune_voyager_images_updated_for_portrait_of_the_eighth_planet.html Ulaan Tsutgalan waterfall: http://en.wikipedia.org/wiki/Orkhon_River#mediaviewer/File:Ulaan-Tsutgalan-waterfall.jpg Perspective on a cloudy day: http://www.slate.com/blogs/bad_astronomy/2014/09/05/clouds_from_space_photo_by_iss_astronaut_oleg_artemyev.html [credit: Oleg Artemyev] Rain droplets: http://commons.wikimedia.org/wiki/File:Rain_droplets.jpg Yellowston Mud Pot: http://en.wikipedia.org/wiki/Liquid_bubble#mediaviewer/File:Yellowstone_mud_pot_p1090998.jpg Sea otters holding hands: http://he.wikipedia.org/wiki/%D7%9C%D7%95%D7%98%D7%A8%D7%AA_%D7%94%D7%99%D7%9D#mediaviewer/File:Sea_otters_holding_hands.jpg Continental Drift: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=73 [credit: NASA/Goddard Space Flight Center Scientific Visualization Studio] Mission to Bennu: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11697 [credit: NASA's Goddard Space Flight Center Conceptual Image Lab] http://www.es.ucsc.edu/~glatz/GarysImages/surf.gif [credit: San Diego Supercomputer Center / Nature] Excerpt from "Dynamic Earth" http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11003 [credit: NASA/Goddard Space Flight Center] Clouds: http://www.beachfrontbroll.com/2013/07/BrightSkyandClouds.html Aurora Borealis: https://www.youtube.com/watch?v=4YjCIoPHT0U [credit: Fotograf Göran Strand] Waves On Rocky Shore 1080 (2011): https://archive.org/details/wavesOnRockyShore-1080 A Year In The Life Of Earth’s CO2: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11719 [credit: NASA's Goddard Space Flight Center] NASA | 2014 Continues Long-Term Global Warming: https://www.youtube.com/watch?v=WtPkFBbJLMg

Join Phil for a tour of our capital-M Moon, from surface features, inside to the core, and back in time to theories about its formation. This episode is brought to you by Squarespace: http://www.squarespace.com/crashcourse -- Table of Contents Many Millions of Moons 0:27 Big Impact on Little Earth 3:42 Craters and Maria 2:15 Water on the Moon? H2O Yeah! 8:06 -- 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 Moon Phase 47.7% http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=3894 [credit: NASA/Goddard Space Flight Center Scientific Visualization Studio] The Blue Marble http://visibleearth.nasa.gov/view.php?id=57723 [credit: Credit: NASA Goddard Space Flight Center Image by Reto Stöckli] Dramatic Moonset http://www.eso.org/public/images/potw1023a/ [credit: G.Gillet/European Southern Observatory] Structure of the Moon: http://en.wikipedia.org/wiki/Moon#mediaviewer/File:Moon_diagram.svg [credit: Kelvin Song via WikiMedia Commons] Crater Science Investigations: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10792 [credit: NASA/Goddard Space Flight Center] Lunar crater Daealus http://commons.wikimedia.org/wiki/File:Lunar_crater_Daedalus.jpg [credit: NASA] Mare Humorum http://commons.wikimedia.org/wiki/File:Mare_Humorum_-_LROC_-_WAC.JPG [credit: NASA] Luna 3: http://nssdc.gsfc.nasa.gov/imgcat/html/object_page/lu3_1.html [credit: NASA] Farside!: http://lroc.sese.asu.edu/posts/298 [credit: NASA/GSFC/Arizona State University] Theia Earth Collision: http://io9.com/the-incredibly-violent-history-of-earths-moon-1098565110 [credit: Ron Miller, used with permission] Earth Seen From Early Moon: http://io9.com/the-incredibly-violent-history-of-earths-moon-1098565110 [credit: Ron Miller, used with permission] Moon Struck: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10931 [credit: NASA's Goddard Space Flight Center] Tycho: http://www.nasa.gov/images/content/417417main_tychofull-20100115-full.jpg [credit: NASA/Goddard/Arizona State University] Double crater on the moon: http://www.esa.int/spaceinimages/Images/2006/09/Double_crater_on_the_Moon [credit: ESA/SPACE-X (Space Exploration Institute)] Stream of Craters: http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc_20090810_craterstream.html [credit: NASA/Goddard Space Flight Center/Arizona State University] Full Moon: http://en.wikipedia.org/wiki/Moon#mediaviewer/File:FullMoon2010.jpg [credit: Gregory H. Revera] Rille on the valley floor, photographic mosaic from Apollo 15: http://en.wikipedia.org/wiki/Schroter%27s_Valley#mediaviewer/File:Vallis_Schroteri.jpg [credit: NASA] New Views of Lunar Pits: http://lroc.sese.asu.edu/posts/230 [credit: NASA/GSFC/Arizona State University] Crater Erlanger: http://www.nasa.gov/mission_pages/Mini-RF/multimedia/erlanger_crater.html [credit: NASA/GSFC/Arizona State University]

Mercury is the closest planet to the sun. It has no atmosphere and is, as such, covered in craters. It's also incredibly hot but, surprisingly, has water ice hiding beneath its surface. -- Table of Contents Closest Planet to the Sun 0:03 Rotation Locked to its 2 to 3 Orbit Ratio 3:10 Deep Crater Water Ice 8:39 -- 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 Mercury relief in Olomouc: http://commons.wikimedia.org/wiki/File:Mercury_relief_in_Olomouc.jpg [credit: Michal Maňas] Mercury: Phil Plait Mercury in color: http://en.wikipedia.org/wiki/File:Mercury_in_color_c1000_700_430.png [credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington] Earth Based View of Mercury: http://airandspace.si.edu/explore-and-learn/multimedia/detail.cfm?id=3726 [credit: Catalina Observatory] Caloris Basin: http://apod.nasa.gov/apod/image/1503/PIA19216MessengerCaloris.jpg [credit: NASA, Johns Hopkins Univ. APL, Arizona State U., CIW] MESSENGER photos: http://messenger.jhuapl.edu/gallery/sciencePhotos/pics/EW1010234404_500_web.jpg http://messenger.jhuapl.edu/gallery/sciencePhotos/pics/EN0108830230M.jpg http://messenger.jhuapl.edu/gallery/sciencePhotos/pics/EW0224377798G.nomap.png [credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington] Mercury’s core: http://astrosun2.astro.cornell.edu/~jlm/out/Mercury/mercury_NSF_printsize.jpg [credit: Nicolle Rager Fuller, National Science Foundation] Mercury’s Ice Lockers: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11184 [credit: NASA Goddard Space Flight Center/Massachusetts Institute of Technology/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington] Mercury’s Tail: http://geeked.gsfc.nasa.gov/wp-content/uploads/2011/03/Mercury_exosphere_600-full.jpg [credit: NASA]

Venus is a gorgeous naked-eye planet, hanging like a diamond in the twilight -- but it’s beauty is best looked at from afar. Even though Mercury is closer to the sun, Venus is the hottest planet in the solar system, due to a runaway greenhouse effect, and has the most volcanic activity in the solar system. Its north and south poles were flipped, causing it to rotate backwards and making for very strange days on this beautiful but inhospitable world. This episode is brought to you by Squarespace http://www.squarespace.com/crashcourse -- Table of Contents Venus’s Size and Atmosphere 3:09 Hottest Planet in the Solar System 4:04 Slow Clockwise Rotation 6:02 Tremendous Volcanic Activity 8:31 -- 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 Naked-eye Venus photo taken by Phil Plait Phases of Venus http://commons.wikimedia.org/wiki/File:Phases-of-Venus2.jpg [credit: Wikimedia Commons] 2012 Venus Transit https://www.youtube.com/watch?v=34mXua1n_FQ [credit: NASA] Black drop effect in 2004 http://en.wikipedia.org/wiki/Black_drop_effect#mediaviewer/File:BlackDrop-Venus-Transit.jpg [credit: Vesta] Venus Transit http://www.nasa.gov/images/content/657111main_1-SOT_120606_venus_ca_nc_yellow_001_color_full.jpg [credit: JAXA/NASA/Lockheed Martin] Venus in real colors http://en.wikipedia.org/wiki/Venus#mediaviewer/File:Venus-real_color.jpg [credit: NASA] Earth http://visibleearth.nasa.gov/view.php?id=57723 [credit: NASA Goddard Space Flight Center, Image by Reto Stöckli] Venus http://www.msss.com/images/science/venus180hem_magellan_big.jpg [credit: NASA/JPL-Caltech/Magellan Project] Atmospheric Drag on Venus https://www.youtube.com/watch?v=aRAonBSIBck [credit: NASA] Lakshmi Planum and Maxwell Montes http://en.wikipedia.org/wiki/Venus_snow#mediaviewer/File:Maxwell_Montes_of_planet_Venus.jpg [credit: NASA/JPL] Artist's impression of the surface of Venus http://sci.esa.int/science-e-media/img/59/VenusSurface.jpg [credit: ESA] Venera Images http://planetimages.blogspot.com/ [credit: Ted Stryk] Venus Globe http://en.wikipedia.org/wiki/Venus#mediaviewer/File:Venus_globe.jpg [credit: NASA] Impact craters on the surface of Venus http://en.wikipedia.org/wiki/Venus#mediaviewer/File:Mgn_p39146.png [credit: Wikimedia Commons] Idunn Mons http://photojournal.jpl.nasa.gov/figures/PIA13001_fig1.jpg [credit: NASA/JPL-Caltech/ESA] Pancake Volcanoes http://en.wikipedia.org/wiki/Pancake_dome#mediaviewer/File:PIA00084_Eistla_region_pancake_volcanoes.jpg [credit: NASA/Jet Propulsion Laboratory]

The fourth planet from the sun and the outermost of the terrestrial planets, Mars has long been a popular spot for missions and imagination. Phil walks you through the planet's topography, core, and features. We'll take a look back to Mars's past and makes predictions for its future, including the possibilities for human life. -- Table of Contents Mars is Colder and Smaller Than Earth 0:56 Polar Ice Caps 3:29 Rusty & Dusty 1:16 Huge Volcanoes 2:32 Mars’s Past Geography 6:33 -- 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 -- PHOTO/VIDEO SOURCES Planets https://en.wikipedia.org/wiki/Solar_System#/media/File:Planets2013.jpg [credit: Wikimedia Commons] Terrestrial Planets https://en.wikipedia.org/wiki/Venus#mediaviewer/File:Terrestrial_Planets_Size_Comp_True_Color.png [credit: Wikimedia Commons] Curiosity’s view of martian soil https://en.wikipedia.org/wiki/Martian_soil#/media/File:PIA17944-MarsCuriosityRover-AfterCrossingDingoGapSanddune-20140209.jpg [credit: NASA/JPL-Caltech/MSSS] Mars Topography http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA02820 [credit: NASA/JPL] Tharsis http://upload.wikimedia.org/wikipedia/commons/thumb/2/22/Tharsis_-_Valles_Marineris_MOLA_shaded_colorized_zoom_32.jpg/1280px-Tharsis_-_Valles_Marineris_MOLA_shaded_colorized_zoom_32.jpg [credit: NASA / JPL-Caltech / Arizona State University] Olympus Mons http://upload.wikimedia.org/wikipedia/commons/0/00/Olympus_Mons_alt.jpg [credit: NASA] Valles Marineris https://en.wikipedia.org/wiki/Valles_Marineris#/media/File:Mars_Valles_Marineris.jpeg [credit: NASA/USGS] Cappuccino swirls at Mars south pole http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2015/02/cappuccino_swirls_at_mars_south_pole/15243840-1-eng-GB/Cappuccino_swirls_at_Mars_south_pole.jpg [credit: ESA/DLR/FU Berlin / Bill Dunford] The Mars Reconnaissance Orbiter image 1 http://static.uahirise.org/images/2015/details/cut/ESP_039148_1980.jpg [credit: NASA] The Mars Reconnaissance Orbiter image 2 http://photojournal.jpl.nasa.gov/figures/PIA19127_fig1.jpg [credit: NASA/JPL] Dunes, image 1 http://mars.jpl.nasa.gov/gallery/press/20090317a/ESP_011909_1320.jpg [credit: NASA/JPL-Caltech/University of Arizona] Dunes, image 2 http://www.nasa.gov/sites/default/files/pia17981.jpg [credit: NASA/JPL-Caltech/Univ. of Arizona] Serpent Dust Devil http://www.nasa.gov/mission_pages/MRO/multimedia/pia15116.html [credit: NASA/JPL-Caltech/Univ. of Arizona] Tattooed Mars http://www.nasa.gov/multimedia/imagegallery/image_feature_1500.html [credit: NASA, HiRISE, MRO, LPL (U. Arizona)] Avalanche http://www.uahirise.org/ESP_016228_2650 [credit: NASA/JPL/University of Arizona] Deimos https://en.wikipedia.org/wiki/Moons_of_Mars#/media/File:Deimos-MRO.jpg [credit: NASA/JPL-Caltech/University of Arizona] Phobos https://en.wikipedia.org/wiki/Moons_of_Mars#/media/File:Phobos_colour_2008.jpg [credit: NASA/JPL-Caltech/University of Arizona] Mars' Moon Phobos Eclipses the Sun, as Seen by Curiosity https://www.youtube.com/watch?v=OyZoD7BRTtg [credit: NASA Jet Propulsion Laboratory] Material Excavated by a Fresh Impact and Identified as Water Ice http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA12220 [credit: NASA/JPL-Caltech/University of Arizona] Crater walls http://www.nasa.gov/externalflash/mgs-20061206/hi-resjpgs/1.jpg [credit: NASA/JPL/Malin Space Science Systems] Sedimentary deposit http://mars.nasa.gov/msl/images/mars-curiosity-rover-mastcam-sedimentary-deposit-lakebed-rocks-pia19074-full.jpg [credit: NASA/JPL-Caltech/MSSS] Curiosity rover http://photojournal.jpl.nasa.gov/jpeg/PIA16764.jpg [credit: NASA/JPL-Caltech/MSSS] Astronaut on Mars http://www.nasa.gov/images/content/114626main_image_feature_326_ys_full.jpg [credit: NASA] Skylight http://static.uahirise.org/images/2011/details/cut/ESP_019351_1795_a.jpg [credit: NASA/JPL-Caltech/Univ. of Arizona] Life on mars http://www.nasa.gov/images/content/107427main_image_feature_261_ajhfull.jpg [credit: NASA/Pat Rawlings, SAIC]

Jupiter is the biggest planet in our solar system. The gas giant is NOT a failed star, but a really successful planet! It has a dynamic atmosphere with belts and zones, as well as an enormous red spot that’s actually a persistent hurricane. Jupiter is still warm from its formation, and has an interior that’s mostly metallic hydrogen, and it may not even have a core. -- Table of Contents Jupiter is the Biggest Planet in Our Solar System 0:28 Belts and Zones 1:33 Persistent Hurricane 2:32 Metallic Hydrogen Interior 4:03 Fast Spin 0:49 Not a Failure 6:17 -- 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 -- PHOTO/VIDEO SOURCES Jupiter http://www.spacetelescope.org/static/archives/images/screen/heic1410a.jpg [credit: NASA, ESA, and A. Simon (Goddard Space Flight Center)] Earth http://visibleearth.nasa.gov/view.php?id=57723 [credit: NASA] Telescope view https://farm7.staticflickr.com/6155/6177104089_ae8cc91af4_o_d.jpg [credit: Chris Isherwood / Flickr] Jupiter Belt System https://en.wikipedia.org/wiki/Atmosphere_of_Jupiter#/media/File:Jupiter_Belt_System.svg [credit: Wikimedia Commons & NASA/JPL] Jupiter’s Jet Streams http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10981 [credit: NASA's Goddard Space Flight Center] 2010 belt sinking http://www.spacetelescope.org/static/archives/images/wallpaper3/heic1010b.jpg [credit: NASA, ESA and Z. Levay (STScI)] Storms http://photojournal.jpl.nasa.gov/jpeg/PIA01384.jpg [credit: NASA/JPL] Jupiter Approach http://www.nasa.gov/centers/goddard/images/content/388625main_Jupiter_Approach.gif [credit: NASA] Red spot shrinking http://imgsrc.hubblesite.org/hu/db/images/hs-2014-24-a-print.jpg [credit: NASA, ESA, and A. Simon (Goddard Space Flight Center)] Jupiter’s Hot Spots http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11237 [credit: NASA's Goddard Space Flight Center] Gas interior http://solarsystem.nasa.gov/multimedia/gallery/gas_interiors.jpg [credit: NASA] Jupiter interior http://juno.wisc.edu/Images/using/Science/Objectives/Jupiter_Interior.jpg [credit: NASA] Creating Gas Giants http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11541 [credit: NASA's Goddard Space Flight Center] Jupiter’s oblate disc https://en.wikipedia.org/wiki/User:Iridia/J_2#/media/File:Jupiter_on_2009-07-23_(captured_by_the_Hubble_Space_Telescope).jpg [credit: WikiMedia Commons/NASA] Jupiter heat http://photojournal.jpl.nasa.gov/jpeg/PIA13760.jpg [credit: NASA/IRTF/JPL-Caltech/University of Oxford] Jupiter and its shrunken red spot https://en.wikipedia.org/wiki/Atmosphere_of_Jupiter#/media/File:Jupiter_and_its_shrunken_Great_Red_Spot.jpg [credit: NASA, ESA, and A. Simon (Goddard Space Flight Center)] Jupiter’s magnetosphere https://en.wikipedia.org/wiki/Io_(moon)#/media/File:Jupiter_magnetosphere_schematic.jpg [credit: WikiMedia Commons / Volcanopele] Jupiter aurora https://solarsystem.nasa.gov/multimedia/gallery/hubblesite_2000_38a.jpg [credit: John Clarke (University of Michigan) and NASA] Jupiter’s ring http://pds-rings.seti.org/jupiter/galileo/PIA01621.jpg [credit: NASA] Cosmic Fireball Falling Over ALMA http://www.eso.org/public/images/potw1414a/ [credit: ESO/C. Malin] Shoemaker http://zebu.uoregon.edu/images/G-MSSSO.gif [credit: ANU / Peter McGregor] Shoemaker scars http://hubblesite.org/hubble_discoveries/10th/photos/graphics/slide21high.jpg [credit: R. Evans, J. Trauger, H. Hammel and the HST Comet Science Team and NASA] Smaller impacts http://imgsrc.hubblesite.org/hu/db/images/hs-2009-23-a-print.jpg [credit: NASA, ESA, and H. Hammel (Space Science Institute, Boulder, Colo.), and the Jupiter Impact Team]

Before moving on from Jupiter to Saturn, we’re going to linger for a moment on Jupiter’s moons. There are 67 known moons, and 4 huge ones that we want to explore in greater detail. Ganymede is the largest - larger, in fact, than any other moon in the solar system and the planet Mercury! Callisto, orbiting the farthest out, is smaller but quite similar to Ganymede in many ways. Io, meanwhile, is most noteworthy for its tremendous volcanic activity. There’s also water on Ganymede and Europa! This episode was brought to you by Squarespace http://www.squarespace.com/crashcourse -- Table of Contents Jupiter Has 67 Moons (4 Big Ones) 0:12 Ganymede is the Largest 1:15 Io is Riddled With Volcanoes 3:16 Europa Has an Undersurface Ocean 4:48 Io, Europa, and Ganymede Interact Gravitationally 3:48 Known Unknowns 8:06 -- 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 -- PHOTO/VIDEO SOURCES Galileo’s notebook http://hos.ou.edu/exhibits/exhibit.php?exbid=4 [credit: Image(s) courtesy History of Science Collections, University of Oklahoma Libraries; copyright the Board of Regents of the University of Oklahoma.] Jupiter’s moons http://photojournal.jpl.nasa.gov/jpeg/PIA00600.jpg [credit: NASA/JPL/DLR] Ganymede http://svs.gsfc.nasa.gov/vis/a010000/a011100/a011173/Image4_1920x1080.jpg [credit: NASA/JPL/Ted Stryk] Interior of Ganymede https://commons.wikimedia.org/wiki/File:PIA00519_Interior_of_Ganymede.jpg [credit: Wikimedia Commons / NASA] Ganymede terrain https://commons.wikimedia.org/wiki/File:Ganymede_terrain.jpg [credit: Wikimedia Commons / NASA] Artist Conception of Ganymede http://www.nasa.gov/content/goddard/hubbles-view-of-ganymede-briefing-materials/ (Figure 5) [credit: NASA/ESA] Callisto http://photojournal.jpl.nasa.gov/jpeg/PIA03456.jpg [credit: NASA/JPL/DLR] Interior of Callisto https://en.wikipedia.org/wiki/Callisto_(moon)#/media/File:PIA01478_Interior_of_Callisto.jpg [credit: Wikimedia Commons / NASA] Valhalla crater on Callisto https://commons.wikimedia.org/wiki/File:Valhalla_crater_on_Callisto.jpg [credit: Wikimedia Commons / NASA / JPL] Io http://svs.gsfc.nasa.gov/vis/a010000/a011400/a011455/s1-1920.jpg [credit: NASA/JPL/USGS] Io volcano image http://solarviews.com/browse/jup/ioplumedisc.jpg [credit: NASA/JPL] Io eruption video http://svs.gsfc.nasa.gov/vis/a010000/a011400/a011455/IO_Eruption-540-MASTER_high.mp4 [credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute] Io surface http://svs.gsfc.nasa.gov/vis/a010000/a011400/a011455/s2-1204.jpg [credit: NASA/JPL/University of Arizona] Jupiter Magnetosphere Schema https://en.wikipedia.org/wiki/Io_(moon)#/media/File:Jupiter_magnetosphere_schematic.jpg [credit: Wikimedia Commons / Volcanopele] Jupiter aurora http://www.spacetelescope.org/static/archives/images/large/heic0009a.jpg [credit: NASA, ESA & John T. Clarke (Univ. of Michigan)] Europa http://photojournal.jpl.nasa.gov/jpeg/PIA19048.jpg [credit: NASA/JPL-Caltech/SETI Institute] Europa ocean http://apod.nasa.gov/apod/image/1205/EuropasOcean_KPHand003.jpg [credit: NASA/JPL/Kevin Hand Habitable zone diagram http://www.keckobservatory.org/images/made/images/gallery/solar_system/Slides-8_1800_1350.jpg [credit: PETIGURA/UC BERKELEY, HOWARD/UH-MANOA, MARCY/UC BERKELEY] Amalthea http://photojournal.jpl.nasa.gov/jpeg/PIA02532.jpg [c redit: NASA/JPL/Cornell University]

Saturn is the crown jewel of the solar system, beautiful and fascinating. It is a gas giant, and has a broad set of rings made of ice particles. Moons create gaps in the rings via their gravity. Saturn has dozens of moons, including Titan, which is as big as Mercury and has a thick atmosphere and lakes of methane; and Enceladus which has an undersurface ocean and eruptions of water geysers. While we are still uncertain, it is entirely possible that either or both moons may support life. This episode was brought to you by Squarespace http://www.squarespace.com -- Table of Contents Saturn is a Gas Giant 0:33 Moons Create Gaps in the Ice Rings 5:17 Dozens of Moons 6:18 Titan’s Methane Lakes 7:56 Enceladus’s Water Geysers 8:33 Life Potential 9:30 -- 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 Saturn http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/IMG004899.jpg [credit: NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic] Interiors http://solarsystem.nasa.gov/multimedia/gallery/gas_interiors.jpg [credit: Lunar and Planetary Institute] Saturn Ring Plane Crossing http://www.spacetelescope.org/static/archives/images/large/opo9616a.jpg [credit: Erich Karkoschka (University of Arizona Lunar & Planetary Lab) and NASA/ESA] Translucent Rings http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA18295 [credit: NASA/JPL-Caltech/Space Science Institute] Catching its Tail http://www.ciclops.org/view_media/34501/Catching_Its_Tail?js=1 [credit: NASA/JPL-Caltech/Space Science Institute] Enter the Vortex http://www.ciclops.org/view_media/38030/Enter_the_Vortex_In_Psychedelic_Color [credit: NASA/JPL/Space Science Institute] The Rose http://www.nasa.gov/mission_pages/cassini/multimedia/pia14944.html#.VSwz-5TF_Z0 [credit: NASA/JPL/Space Science Institute] Ice http://www.nasa.gov/images/content/205796main_PIA10081-hires.jpg [credit: NASA/JPL/University of Colorado] Saturn’s rings to scale http://www.slate.com/blogs/bad_astronomy/2014/05/02/saturn_s_rings_to_scale_thinner_than_paper.html [credit: NASA/JPL/Space Science Institute] Saturn’s Ring Plane http://en.wikipedia.org/wiki/Rings_of_Saturn#/media/File:Saturn%27s_ring_plane.jpg [credit: NASA/JPL/Space Science Institute - Cassini-Huygens/NASA] Saturn http://saturn.jpl.nasa.gov/multimedia/images/saturn/images/IMG004899.jpg [credit: NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic] Shaping the Drapes (video) http://ciclops.org/view.php?id=1361&js=1 [credit: NASA/JPL/Space Science Institute] Peaks http://en.wikipedia.org/wiki/Rings_of_Saturn#/media/File:PIA11668_B_ring_peaks_2x_crop.jpg [credit: NASA / Jet Propulsion Lab / Space Science Institute] Mimas Cassini http://en.wikipedia.org/wiki/Mimas_(moon)#/media/File:Mimas_Cassini.jpg [credit: NASA / JPL-Caltech / Space Science Institute] Cassini NAC RGB https://www.flickr.com/photos/ugordan/6896462870/sizes/o/in/photostream/ [credit: NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic] Titan http://en.wikipedia.org/wiki/Titan_(moon)#/media/File:Titan2005.jpg [credit: NASA/JPL/Space Science Institute] Titan’s Nile River http://www.esa.int/spaceinimages/Images/2012/11/Titan_s_Nile_River [credit: NASA/JPL–Caltech/ASI] Lakes http://photojournal.jpl.nasa.gov/figures/PIA17655_fig1.jpg [credit: NASA/JPL-Caltech/ASI/USGS] Enceladus http://www.ciclops.org/view_media/39541/Bursting-at-the-Seams [credit: NASA/JPL/Space Science Institute] Iapetus Ridge http://en.wikipedia.org/wiki/Equatorial_ridge#/media/File:Iapetus_706_1419_1.jpg [credit: NASA (Cassini probe), Matt McIrvin (image mosaic)] Hyperion http://ciclops.org/media/ir/2005/1507_3730_1.jpg [credit: NASA/JPL/Space Science Institute] Saturn eclipse mosaic http://en.wikipedia.org/wiki/Rings_of_Saturn#/media/File:PIA17172_Saturn_eclipse_mosaic_bright_crop.jpg [credit: NASA / JPL-Caltech / Space Science Institute]

Today we’re rounding out our planetary tour with ice giants Uranus and Neptune. Both have small rocky cores, thick mantles of ammonia, water, and methane, and atmospheres that make them look greenish and blue. Uranus has a truly weird rotation and relatively dull weather, while Neptune has clouds and storms whipped by tremendous winds. Both have rings and moons, with Neptune’s Triton probably being a captured iceball that has active geology. This episode was brought to you by Squarespace http://www.squarespace.com/crashcourse -- Table of Contents Ice Giants With Small Rocky Cores 2:18 Thick Mantles of Ammonia, Water, and Methane 1:53 Atmospheres Makes Them Look Green And Blue 2:53 Uranus Has Dull Weather 3:35 Neptune Has Active Weather 7:19 Both Have Rings And Moons 5:12 -- 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 Uranus http://en.wikipedia.org/wiki/Voyager_2#/media/File:Uranus2.jpg [credit: NASA/JPL/Voyager mission] Neptune https://www.nasa.gov/content/25-years-ago-voyager-2-captures-images-of-neptune/ [credit: NASA] King George III http://en.wikipedia.org/wiki/George_III_of_the_United_Kingdom#/media/File:Allan_Ramsay_-_King_George_III_in_coronation_robes_-_Google_Art_Project.jpg Uranus from Earth picture by Phil Plait Uranus, Earth size comparison http://en.wikipedia.org/wiki/File:Uranus,_Earth_size_comparison.jpg [credit: NASA] Uranus core, reconstructed from http://en.wikipedia.org/wiki/File:Uranus-intern-en.png [credit: Wikimedia Commons] Uranus http://www.spacetelescope.org/static/archives/images/screen/opo0647b.jpg [credit: NASA, ESA, L. Sromovsky and P. Fry (University of Wisconsin), H. Hammel (Space Science Institute), and K. Rages (SETI Institute)] Uranus storms http://www.keckobservatory.org/images/made/images/blog/Uranus_Aug20142_800_407.jpg [credit: Imke de Pater (UC–Berkeley)/Keck Observatory] Uranus and rings (tilt demonstration) http://en.wikipedia.org/wiki/Uranus#/media/File:Uranusandrings.jpg [credit: Hubble Space Telescope - NASA Marshall Space Flight Center] Uranus with rings and moons http://www.eso.org/public/images/eso0237a/ [credit: ESO] Miranda http://en.wikipedia.org/wiki/Moons_of_Uranus#/media/File:Miranda.jpg [credit: NASA] Verona Rupes http://apod.nasa.gov/apod/ap110404.html [credit: NASA] Neptune’s Interior https://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=283 [credit: Lunar and Planetary Institute] Neptune clouds http://en.wikipedia.org/wiki/File:Neptune_clouds.jpg [credit: NASA] Neptune’s Great Dark Spot http://en.wikipedia.org/wiki/Neptune#/media/File:Neptune%27s_Great_Dark_Spot.jpg [credit: NASA / Jet Propulsion Lab] Neptune’s Rings http://www.rolfolsenastrophotography.com/Astrophotography/Solar-System/i-vjMHSxz/A [credit: Rolf Wahl Olsen / NASA/JPL (Voyager 2, NASA Planetary Data System)] Triton http://en.wikipedia.org/wiki/Triton_(moon)#/media/File:Triton_moon_mosaic_Voyager_2_(large).jpg [credit: NASA / Jet Propulsion Lab / U.S. Geological Survey] Triton flipped http://en.wikipedia.org/wiki/File:PIA01538_Triton_flipped_v.jpg [credit: NASA/JPL] Triton Nitrogen Geysers http://en.wikipedia.org/wiki/Triton_(moon)#/media/File:Voyager_2_Triton_14bg_r90ccw_colorized.jpg[credit: NASA]

Now that we’ve finished our tour of the planets, we’re headed back to the asteroid belt. Asteroids are chunks of rock, metal, or both that were once part of smallish planets but were destroyed after collisions. Most orbit the Sun between Mars and Jupiter, but some get near the Earth. The biggest, Ceres is far smaller than the Moon but still big enough to be round and have undergone differentiation. CORRECTION: In the episode we say that 2010 TK7 is 800 km away. However, 2010 TK7 stays on average 150 million kilometers from Earth, but that can vary wildly. Sorry about that! -- Table of Contents Asteroids Are Chunks of Rock, Metal, or Both 1:45 Most Orbit the Sun Between Mars and Jupiter 7:16 Ceres is Far Smaller Than the Moon, But Large Enough to be Round 3:43 -- 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 Timelapse of Asteroid 2004 FH's flyby http://en.wikipedia.org/wiki/File:Asteroid_2004_FH.gif [credit: NASA/JPL Public Domain] Asteroid Discovery Video https://www.youtube.com/watch?v=2k2vkLEE4ko [credit: Scott Manley - [email protected]] Inner Solar System http://en.wikipedia.org/wiki/File:InnerSolarSystem-en.png [credit: Wikimedia Commons] Kirkwood gaps http://commons.wikimedia.org/wiki/File:Kirkwood-gaps-as-disk.png [credit: Wikimedia Commons] Ceres, Earth & Moon size comparison http://en.wikipedia.org/wiki/File:Ceres,_Earth_%26_Moon_size_comparison.jpg [credit: NASA] Dawn Glimpses Ceres’ North Pole http://www.jpl.nasa.gov/news/news.php?release=2015-133 [credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA] Ceres cutaway http://commons.wikimedia.org/wiki/File:Ceres_Cutaway.jpg [credit: NASA, ESA, and A. Feild (STScI)] Bright Spot on Ceres Has Dimmer Companion http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA19185 [credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA] Vesta http://en.wikipedia.org/wiki/4_Vesta#/media/File:Vesta_full_mosaic.jpg [credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA] Lutetia http://en.wikipedia.org/wiki/21_Lutetia#/media/File:Lutetia_closest_approach_(Rosetta).jpg [credit: ESA] Gaspra http://commons.wikimedia.org/wiki/File:Galileo_Gaspra_Mosaic.jpg [credit: NASA] Steins http://neo.ssa.esa.int/image/image_gallery?uuid=db747cf5-9d21-405e-bcdb-e70fe475edc9&groupId=10157&t=1340734455649 [credit: ESA/Osiris] Mathilde http://neo.jpl.nasa.gov/images/mathilde1.jpg [credit: NEAR Spacecraft Team, JHUAPL, NASA] Ida http://en.wikipedia.org/wiki/243_Ida#/media/File:243_ida_crop.jpg [credit: NASA/JPL] Kleopatra http://apod.nasa.gov/apod/ap000510.html [credit: Stephen Ostro et al. (JPL), Arecibo Radio Telescope, NSF, NASA] An artist's conception of two Pluto-sized dwarf planets in a collision around Vega. http://en.wikipedia.org/wiki/Methods_of_detecting_exoplanets#/media/File:Massive_Smash-Up_at_Vega.jpg [credit: NASA/JPL-Caltech/T. Pyle (SSC)] Itokawa http://apod.nasa.gov/apod/ap140209.html [credit: ISAS, JAXA] An artist's illustration showing two asteroid belts and a planet orbiting Epsilon Eridani http://en.wikipedia.org/wiki/Epsilon_Eridani#/media/File:NASA-JPL-Caltech_-_Double_the_Rubble_(PIA11375)_(pd).jpg [credit: NASA/JPL-Caltech] Near-Earth Asteroids http://www.jpl.nasa.gov/images/asteroid/20130204/asteroid20130204-full.jpg [credit: NASA/JPL-Caltech] Lagrange Points Diagram http://en.wikipedia.org/wiki/Trojan_(astronomy)#/media/File:Lagrange_very_massive.svg [credit: Wikimedia Commons] TK7 http://en.wikipedia.org/wiki/2010_TK7#/media/File:PIA14405-full_crop.jpg [credit: NASA/JPL-Caltech/UCLA] 165347 Philplait http://www.slate.com/content/dam/slate/blogs/bad_astronomy/2014/01/20/asteroidphilplait_panstarrs.jpg.CROP.original-original.jpg [credit: Larry Denneau/Pan-STARRS via Amy Mainzer]

Today on Crash Course Astronomy, Phil explains comets. Comets are chunks of ice and rock that orbit the Sun. When they get near the Sun the ice turns into gas, forming the long tail, and also releases dust that forms a different tail. We’ve visited comets up close and found them to be lumpy, with vents in the surface that release the gas as ice sublimates. Eons ago, comets (and asteroids) may have brought a lot of water to Earth -- as well as the ingredients for life. -- Table of Contents Comets Are Chunks of Rock and Ice That Orbit the Sun 1:26 When They Get Near the Sun They Turn Into Gas 2:08 Comets Release Gas Via Vents As Ice Sublimates 2:15 Comets May Have Brought Water and Ingredients for Life to Earth 9:30 -- 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 Halley's Comet, 1910 http://en.wikipedia.org/wiki/File:Halley%27s_Comet,_1910.JPG [credit: New York Times, Wikimedia Commons] Bayeux Tapestry http://upload.wikimedia.org/wikipedia/commons/f/fa/Bayeux_Tapestry_32-33_comet_Halley_Harold.jpg [credit: Wikimedia Commons] Comet McNaught [credit: Phil Plait] Comet McNaught + tail http://en.wikipedia.org/wiki/C/2006_P1#/media/File:Cometmcnaughtchrisn1.jpg [credit: Chris North, Wikimedia Commons] Comet surface http://rosetta.jpl.nasa.gov/sites/default/files/PIA18867-MAIN_Nov9-15765234852_c16c4097a5_o.jpg [credit: ESA/Rosetta/NAVCAM] Fine structure in the comet’s jets http://blogs.esa.int/rosetta/2015/01/16/fine-structure-in-the-comets-jets/ [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA] Comet Halley http://apod.nasa.gov/apod/image/1001/halley_giotto_big.jpg [credit: Halley Multicolor Camera Team, Giotto Project, ESA] Comet McNaught https://solarsystem.nasa.gov/multimedia/display.cfm?Category=Planets&IM_ID=10194 [credit: ESO] Hubble's Last Look at Comet ISON Before Perihelion http://en.wikipedia.org/wiki/File:Hubble%27s_Last_Look_at_Comet_ISON_Before_Perihelion.jpg [credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)] Hale-Bopp: The Great Comet of 1997 http://apod.nasa.gov/apod/ap131013.html [credit: Jerry Lodriguss, used with permission] Sungrazer video http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11307 [credit: NASA's Goddard Space Flight Center] “Large Web” graphic http://www.nasa.gov/sites/default/files/hs-2014-29-a-large_web.jpg [credit: JHUAPL/SwRI/Dan Durda] Comet Daniel http://commons.wikimedia.org/wiki/File:Comet_Daniel_-_1907.jpg [credit: Max Wolf, Wikimedia Commons] Vega 1 Low Res http://nssdc.gsfc.nasa.gov/planetary/image/veg2_tikf0002.gif [credit: Russian Academy of Sciences] The Nucleus of Comet Halley http://sci.esa.int/giotto/51183-the-nucleus-of-comet-halley/ [credit: ESA/MPS] Comet Hartley 2 http://en.wikipedia.org/wiki/103P/Hartley#/media/File:495296main_epoxi-1-full_full.jpg [credit: NASA/JPL-Caltech/UMD] Comet 67P/Churyumov-Gerasimenko http://sci.esa.int/rosetta/54472-comet-67p-on-3-august-2014/ [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA] OSIRIS Catches Activity in the Act http://blogs.esa.int/rosetta/2015/04/20/osiris-catches-activity-in-the-act/ [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA] Active Pit http://www.esa.int/spaceinimages/Images/2015/01/Active_pit [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA] Depiction of Philae‍‍ '​‍s planned touchdown on the comet http://en.wikipedia.org/wiki/Philae_(spacecraft)#/media/File:Rosetta%27s_Philae_touchdown.jpg [credit: DLR, CC-BY 3.0, Wikimedia Commons] Colour Image of a Comet http://www.esa.int/spaceinimages/Images/2014/12/Colour_image_of_comet [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA] Comet Lovejoy http://en.wikipedia.org/wiki/C/2011_W3_(Lovejoy)#/media/File:Iss030e015472_Edit.jpg [credit: NASA/Dan Burbank] NASA’s Stardust http://www.nasa.gov/images/content/361283main_sd_comet_2400x3000.jpg [credit: NASA/JPL] Comet dust https://www.nasa.gov/images/content/141271main_jsc2006e01008_high.jpg [credit: NASA] Comet Lovejoy http://www.eso.org/public/usa/images/dsc_5682-cc/ [credit: ESO/G. Brammer]

Now that we’re done with the planets, asteroid belt, and comets, we’re heading to the outskirts of the solar system. Out past Neptune are vast reservoirs of icy bodies that can become comets if they get poked into the inner solar system. The Kuiper Belt is a donut shape aligned with the plane of the solar system; the scattered disk is more eccentric and is the source of short period comets; and the Oort Cloud which surrounds the solar system out to great distances is the source of long-period comets. These bodies all probably formed closer into the Sun, and got flung out to the solar system’s suburbs by gravitational interactions with the outer planets. -- Table of Contents Icy Bodies That Can Become Comets 0:27 The Kuiper Belt is a Donut Shape Aligned With the Plane of the Solar System 2:57 The Scattered Disk is More Eccentric and the Source of Short Period Comets 4:26 Oort Cloud Surrounds Our Solar System and is the Source of Long-Period Comets 4:04 These Bodies Probably Formed Near the Sun and Dispersed Through Gravitational Interactions 5:41 -- 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 HD Long Exposure Star Timelapse https://vimeo.com/34172172 [credit: Jeffrey Beach, Beachfront B-Roll] Fine Structure in the Comet’s Jets http://blogs.esa.int/rosetta/2015/01/16/fine-structure-in-the-comets-jets/ http://en.wikipedia.org/wiki/Protoplanetary_disk#mediaviewer/File:Artist%E2%80%99s_Impression_of_a_Baby_Star_Still_Surrounded_by_a_Protoplanetary_Disc.jpg [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA] Artist's impression of a protoplanetary disk. [credit: ESO/L. Calçada - ESO] Creating Gas Giants http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11541 [credit: NASA's Goddard Space Flight Center] What is a Sungrazing Comet? http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11307 [credit: NASA's Goddard Space Flight Center] Pluto/Neptune Orbit http://www2.jpl.nasa.gov/files/images/browse/plutoneptune.gif [credit: NASA] 1992 QB1 http://solarsystem.nasa.gov/multimedia/gallery/1992_QB14.jpg [credit: ESO] Eris http://apod.nasa.gov/apod/ap060918.html [credit: W. M. Keck Observatory] Moons of Pluto http://en.wikipedia.org/wiki/Kerberos_(moon)#/media/File:Moons_of_Pluto.png [credit: NASA, ESA, and M. Showalter (SETI institute)] New Horizons Approach http://pluto.jhuapl.edu/common/content/animations/New-Horizons-Voyage-to-Pluto/ApproachingPluto1280.mp4 [credit: JHUAPL] Moon http://svs.gsfc.nasa.gov/vis/a000000/a003800/a003894/phase04_full.jpg [credit: NASA/Goddard Space Flight Center Scientific Visualization Studio] Pluto http://solarsystem.nasa.gov/multimedia/display.cfm?Category=Planets&IM_ID=20073 [credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute] Sedna’s Orbit http://commons.wikimedia.org/wiki/File:Sedna-PIA05569-crop.jpg [credit: NASA] Artist’s Conception of Kuiper Belt http://en.wikipedia.org/wiki/File:14-281-KuiperBeltObject-ArtistsConcept-20141015.jpg [credit: NASA, Wikimedia Commons] Kuiper Belt World (video) http://planetquest.jpl.nasa.gov/video/41 [credit: NASA Kepler Mission/Dana Berry] Pluto Discovery Plates http://azmemory.azlibrary.gov/cdm/singleitem/collection/loaselect/id/25/rec/1 [credit: Clyde Tombaugh, Lowell Observatory]

Today Phil helps keep you from ticking off an astronomer in your life by making sure you know the difference between a meteor, meteorite, and meteoroid. When the Earth plows through the stream emitted by a comet we get a meteor shower. Meteors burn up about 100 km above the Earth, but some survive to hit the ground. Most of these meteorites are rocky, some are metallic, and a few are a mix of the two. Very big meteorites can be a very big problem, but there are plans in the works to prevent us from going the way of the dinosaurs. Meteorite Links: Aerolite Meteorites, Inc.: http://www.aerolite.org/ Big Kahuna Meteorites: http://bigkahuna-meteorites.com/ Arizona Skies Meteorites: http://www.arizonaskiesmeteorites.com/ -- Table of Contents What Meteors Are 0:59 Meteor Shower 4:22 What Meteors Are Made Of 7:10 Very Big Meteorites Can Be a Very Big Problem 8:36 -- 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 Shooting star http://dakotalapse.com/wp-content/uploads/2013/02/IMG_5555-reboot1.jpg [credit: Randy Halverson / Dakotalapse.com] Cosmic Fireball Falling Over ALMA http://www.eso.org/public/usa/images/potw1414a/ [credit: ESO / Christoph Malin] Meteor light https://sphotos-b.xx.fbcdn.net/hphotos-ash3/704204_406950402710734_1157020008_o.jpg [credit: Randy Halverson / Dakotalapse.com] Bolide 10/16/14 https://www.youtube.com/watch?v=GZXqmPhd8AQ [credit: reddit user -545-] Meteor Video http://svs.gsfc.nasa.gov/vis/a010000/a010700/a010747/10747_Swift_Asteroid_H264_Good_1280x720_29.97.mov [credit: NASA/Goddard Space Flight Center] Orbit Video http://svs.gsfc.nasa.gov/vis/a000000/a004100/a004159/209PLINEAR-swingAround.slate.HD1080.mp4 [credit: NASA's Scientific Visualization Studio] When Gemini Sends Stars to Paranal http://twanight.org/newTWAN/photos.asp?ID=3003955 [credit: Stephane Guisard] Perseid below space station http://apod.nasa.gov/apod/image/1208/iss028e024847perseid.jpg [credit: NASA] Geminids shower http://www.slate.com/blogs/bad_astronomy/2014/12/15/geminids_meteor_shower_photo.html [credit: Neil Zeller] Cygnus Reentry http://www.slate.com/blogs/bad_astronomy/2014/08/18/fireball_astronauts_photograph_cygnus_resupply_ship_burning_up.html [credit: ESA/NASA] Stony meteorite http://en.wikipedia.org/wiki/File:AllendeMeteorite.jpg [credit: Wikimedia Commons, H. Raab] Iron meteorite http://commons.wikimedia.org/wiki/File:Nickel-iron_meteorite_fragment,_5.5_billion_years_old,_found_near_Flagstaff_AZ_-_Franklin_Institute_-_DSC06707.JPG [credit: Wikimedia Commons, Daderot] Stony iron meteorite http://en.wikipedia.org/wiki/Pallasite#/media/File:Bernham_meteorite_sept_2010.JPG [credit: Wikimedia Commons, Supportstorm] Chondrites http://commons.wikimedia.org/wiki/File:Allende_meteorite,_carbonaceous_chondrite_(14787764392).jpg [credit: Wikimedia Commons, James St. John] Pallasite https://www.flickr.com/photos/jsjgeology/14608975850/ [credit: James St. John] Aftermath of Chelyabinsk Meteor https://www.youtube.com/watch?v=Q9KwK0izt5c [credit: NASA] Near-Earth asteroid 2013 https://www.youtube.com/watch?v=RmPsQdEHyPU [credit: Gianluca Masi, permission granted by author] Dinosaur drawing courtesy of Zach Weiner of Saturday Morning Breakfast Cereal http://www.smbc-comics.com/?id=1535

In order to understand how we study the universe, we need to talk a little bit about light. Light is a form of energy. Its wavelength tells us its energy and color. Spectroscopy allows us to analyze those colors and determine an object’s temperature, density, spin, motion, and chemical composition. Crash Course Chemistry posters are available at DFTBA.com http://www.dftba.com/crashcourse -- Table of Contents Light is a Form of Energy 0:39 Wavelength Tells Us Its Energy and Color 0:59 Spectroscopy 7:28 -- 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 Wavelengths http://imagine.gsfc.nasa.gov/educators/gammaraybursts/starchild/Image6.gif [credit: Imagine the Universe! / NASA] Observatories across spectrum http://imagine.gsfc.nasa.gov/Images/science/observatories_across_spectrum_full.jpg [credit: Imagine the Universe! / NASA] Red hot spiral hotplate http://freefoodphotos.com/imagelibrary/cooking/slides/hot_electric_cooker.html [credit: freefoodphotos.com] The Crab Nebula http://en.wikipedia.org/wiki/Nebula#/media/File:Crab_Nebula.jpg [credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)] Building the Space Telescope Imaging Spectograph http://imgsrc.hubblesite.org/hu/gallery/db/spacecraft/18/formats/18_print.jpg [credit: NASA] VST images the Lagoon Nebula http://en.wikipedia.org/wiki/Lagoon_Nebula#/media/File:VST_images_the_Lagoon_Nebula.jpg [credit: ESO/VPHAS+ team] Jupiter http://www.nasa.gov/images/content/414987main_pia09339.jpg [credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute] Venus http://en.wikipedia.org/wiki/Atmosphere_of_Venus#/media/File:Venuspioneeruv.jpg [credit: NASA - NSSDC Photo Gallery Venus] Ring Around SN 1987a, image 1 http://www.spacetelescope.org/images/opo9714e/ [credit: Jason Pun (NOAO) and SINS Collaboration] Ring Around SN 1987a, image 2 http://www.spacetelescope.org/images/opo9714a/ [credit: George Sonneborn (GSFC) and NASA/ESA]

How do astronomers make sense out of the vastness of space? How do they study things so far away? Today Phil talks about distances, going back to early astronomy. Ancient Greeks were able to find the size of the Earth, and from that the distance to and the sizes of the Moon and Sun. Once the Earth/Sun distance was found, parallax was used to find the distance to nearby stars, and that was bootstrapped using brightness to determine the distances to much farther stars. -- Table of Contents Ancient Greeks Finding the Size of the Earth 1:07 Earth/Sun Distance Began Our Use of Parallax 5:39 Brightness Relation to Distance 9:07 -- 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 Lunar Ecplise http://www.slate.com/content/dam/slate/blogs/bad_astronomy/2014/04/15/lunareclipse_partial_apr142014_spica.jpg.CROP.original-original.jpg [credit: Phil Plait] Venus & Mercury [credit: Phil Plait] Venus Transit https://www.youtube.com/watch?v=34mXua1n_FQ [credit: NASA] Black Drop Venus Transit https://en.wikipedia.org/wiki/Black_drop_effect#mediaviewer/File:BlackDrop-Venus-Transit.jpg [credit: Wikimedia Commons, H. Raab, Johannes-Kepler-Observatory] New Horizons Approaching Pluto and Charon https://en.wikipedia.org/wiki/New_Horizons#/media/File:15-011a-NewHorizons-PlutoFlyby-ArtistConcept-14July2015-20150115.jpg [credit: NASA/JHU APL/SwRI/Steve Gribben] Radio Telescopes Diagram http://scitechdaily.com/images/Radio-Telescopes-Settle-Controversy-Over-Distance-to-Pleiades.jpg [credit: Alexandra Angelich, NRAO/AUI/NSF] 61 Cygni https://archive.stsci.edu/cgi-bin/dss_search?v=poss1_red&r=21+06+54.60&d=%2B38+44+44.9&e=J2000&h=30&w=30&f=gif&c=none&fov=NONE&v3= [credit: Caltech / National Geographic Society / STScI] Proxima Centauri https://www.spacetelescope.org/images/potw1343a/ [credit: ESA/Hubble & NASA] Dying Star http://www.nasa.gov/images/content/64884main_image_feature_211_jwfull.jpg [credit: NASA, ESA, HEIC, and The Hubble Heritage Team (STScI/AURA)] Exploding Star http://www.nasa.gov/multimedia/imagegallery/image_feature_1604.html [credit: NASA, ESA, J. Hester, A. Loll (ASU)] Animation of a Variable Star http://www.spacetelescope.org/videos/heic1323j/ [credit: NASA, ESA, M. Kornmesser] Hubble's High-Definition Panoramic View of the Andromeda Galaxy http://hubblesite.org/newscenter/archive/releases/2015/02/image/a/ [credit: NASA, ESA, J. Dalcanton, B.F. Williams, and L.C. Johnson (University of Washington), the PHAT team, and R. Gendler]

Today Phil’s explaining the stars and how they can be categorized using their spectra. Together with their distance, this provides a wealth of information about them including their luminosity, size, and temperature. The HR diagram plots stars’ luminosity versus temperature, and most stars fall along the main sequence, where they live most of their lives. -- Table of Contents Stars Can Be Categorized Using Their Spectra 1:32 Spectra With Distance Can Identify Luminosity, Size, and Temperature 5:20 The HR Diagram Plots Luminosity vs Temperature 6:33 Most Stars Fall Along the Main Sequence 7:16 -- 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 Stars http://www.nasa.gov/images/content/703724main_potw1244a.jpg [credit: ESA/Hubble & NASA] Spitzer Spectrum http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA03242 [credit: NASA/JPL-Caltech/Leiden/SRON] Sun spectrum https://www.noao.edu/image_gallery/html/im0600.html [credit: N.A.Sharp, NOAO/NSO/Kitt Peak FTS/AURA/NSF] Annie Jump Cannon https://en.wikipedia.org/wiki/Annie_Jump_Cannon#/media/File:Annie_Jump_Cannon_1922_Portrait.jpg [credit: New York World-Telegram and the Sun Newspaper] Cecilia Payne-Gaposchkin https://en.wikipedia.org/wiki/Cecilia_Payne-Gaposchkin#/media/File:Cecilia_Helena_Payne_Gaposchkin_(1900-1979)_(3).jpg [credit: Smithsonian Institution] OBAFGKM https://www.noao.edu/image_gallery/html/im0649.html [credit: NOAO/AURA/NSF] Betelgeuse http://www.eso.org/public/usa/images/eso0927e/ [credit: ESO/Digitized Sky Survey 2. Acknowledgment: Davide De Martin] Sirius https://www.nasa.gov/multimedia/imagegallery/image_feature_468.html [credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester)] Solar AM0 spectrum with visible spectrum background https://commons.wikimedia.org/wiki/File:Solar_AM0_spectrum_with_visible_spectrum_background_(en).png [credit: Danmichaelo, Wikimedia Commons] Blue sky http://www.pexels.com/photo/sky-sunny-clouds-cloudy-3768/ [credit: Skitter Photo] Hawaii sunset photo [credit: Phil Plait] Hertzsprung-Russell Diagram https://commons.wikimedia.org/wiki/File:ESO_-_Hertzsprung-Russell_Diagram_(by).jpg [credit: ESO]

Today Phil explains that YES, there are other planets out there and astonomers have a lot of methods for detecting them. Nearly 2000 have been found so far. The most successful method is using transits, where a planet physically passes in front of its parent star, producing a measurable dip in the star’s light. Another is to measuring the Doppler shift in a star’s light due to reflexive motion as the planet orbits. Exoplanets appear to orbit nearly every kind of star, and we’ve even found planets that are the same size as Earth. We think there may be many billions of Earth-like planets in our galaxy. This is a reupload of last week's episode to correct an error in the way we covered reflexive motion. For more information on the change and reflexive motion, you can check out Phil's blog: http://www.slate.com/blogs/bad_astronomy/2015/08/07/crash_course_astronomy_exoplanets.html -- Table of Contents Other Planets Orbit Other Stars 2:10 Nearly 2000 Have Been Found 9:29 Transits 5:44 Doppler Shift 3:30 Exoplanets Orbit Nearly Every Kind of Star 8:44 Billions of Earth-Like Planets 9:33 -- 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 Stars as viewed from ISS https://www.youtube.com/watch?v=TOQrx-7qgak [credit: Alex Rivest & NASA] Jupiter http://www.nasa.gov/centers/goddard/multimedia/largest/Jupiter_sphere.jpg.html [credit: NASA] Mars http://mars.jpl.nasa.gov/multimedia/images/?ImageID=2633 [credit: NASA/JPL-Caltech/MSSS] Mercury http://solarsystem.nasa.gov/multimedia/display.cfm?Category=Planets&IM_ID=7543 [credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington] Earth https://www.nasa.gov/topics/earth/overview/index.html [credit: NASA] Uranus http://photojournal.jpl.nasa.gov/catalog/PIA18182 [credit: NASA/JPL-Caltech] Lost in the Glare http://planetquest.jpl.nasa.gov/video/23 [credit: NASA Kepler Mission/Dana Berry] Reflexive Motion gifs http://spaceplace.nasa.gov/barycenter/en/ [credit: NASA] Artist's conception of PSR B1257+12's system of planets https://en.wikipedia.org/wiki/Pulsar_planet#/media/File:Artist%27s_concept_of_PSR_B1257%2B12_system.jpg [credit: NASA/JPL-Caltech/R. Hurt (SSC)] Artist’s impression of the exoplanet 51 Pegasi b (image) http://www.eso.org/public/usa/images/eso1517a/ [credit: ESO/M. Kornmesser/Nick Risinger (skysurvey.org)] Artist’s impression of the exoplanet 51 Pegasi b (video) http://www.eso.org/public/usa/videos/eso1517b/ [credit: ESO/M. Kornmesser/Nick Risinger (skysurvey.org)] Kepler Transit Graph http://planetquest.jpl.nasa.gov/video/22 [credit NASA Kepler Mission/Dana Berry] Kepler “Beauty Shot” http://planetquest.jpl.nasa.gov/video/2 [credit: NASA/Kepler mission/Dana Berry] The Brown Dwarf 2M1207 and its Planetary Companion https://www.eso.org/public/usa/images/eso0515a/ [credit: ESO] Beta Pictoris b http://www.eso.org/public/archives/images/screen/eso1024c.jpg [credit: ESO] A size comparison of the planets in the Kepler-37 system and objects in the Solar System http://photojournal.jpl.nasa.gov/catalog/PIA16694 [credit: NASA/Ames/JPL-Caltech] Water World http://planetquest.jpl.nasa.gov/video/39 [credit: NASA Kepler Mission/Dana Berry] Earth-like World http://planetquest.jpl.nasa.gov/video/42 [credit: NASA Kepler Mission/Dana Berry]

While Jupiter is nowhere near massive enough to initiate fusion in its core, there are even more massive objects out there that fall just short of that achievement as well called brown dwarfs. Brown dwarfs, have a mass that places them between giant planets and small stars. They were only recently discovered in the 1990’s, but thousands are now known. More massive ones can fuse deuterium, and even lithium, but not hydrogen, distinguishing them from “normal” stars. Sort of. Correction: In the illustration at 9:30, the numbers listed after the star names are the year of discovery, not distance. -- Table of Contents Intermediate in Mass 1:22 Thousands Are Known 4:48 Cannot Fuse Hydrogen Like “Normal” Stars 8:46 -- 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 The sun in extreme ultraviolet https://en.wikipedia.org/wiki/File:The_Sun_in_extreme_ultraviolet.jpg [credit: NASA, ESA / Wikimedia Commons] Jupiter http://www.spacetelescope.org/static/archives/images/screen/heic1410a.jpg [credit: NASA, ESA, and A. Simon (Goddard Space Flight Center)] Forming a Planetary Gap http://www.spitzer.caltech.edu/video-audio/691-ssc2004-08v3-Forming-a-Planetary-Gap [credit: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)] Exoplanet http://uanews.org/sites/default/files/story-images/exoplanet.jpg [credit: NASA/JPL-Caltech] A Trio of Brown Dwarfs (L/T/Y) http://www.nasa.gov/mission_pages/WISE/multimedia/pia14722.html [credit: NASA/JPL-Caltech] Artist's concept of a T-type brown dwarf https://en.wikipedia.org/wiki/Brown_dwarf#/media/File:2MASSJ22282889-431026.jpg [credit: NASA/JPL-Caltech] Brown Dwarf Gliese 229B https://en.wikipedia.org/wiki/File:Brown_Dwarf_Gliese_229B.jpg [credit: NASA / Wikimedia Commons] Gliese 229B Spectrum - image provided by Phil Plait [credit: NASA/ESA/Hubble/Al Schultz et al] Artist's vision of a T-dwarf https://en.wikipedia.org/wiki/Brown_dwarf#/media/File:T-dwarf-nasa-hurt.png [credit: R. Hurt/NASA - R. Hurt/NASA, Wikimedia Commons] First Ultra-Cool WISE Brown Dwarf http://wise.ssl.berkeley.edu/gallery_firstbd.html [credit: NASA/JPL-Caltech/WISE Team] Brown Dwarf Comparison http://www.nasa.gov/mission_pages/WISE/multimedia/pia12462.html [credit: NASA/JPL-Caltech/UCB] Storms Expected on Brown Dwarfs http://www.spitzer.caltech.edu/images/5718-sig14-001-This-Just-In-Storms-Expected-on-Brown-Dwarfs [credit: NASA/JPL-Caltech/T. Pyle (IPAC)] Stars and brown dwarfs closest to the Sun https://en.wikipedia.org/wiki/Luhman_16#/media/File:PIA18003-NASA-WISE-StarsNearSun-20140425-2.png [credit: NASA/Penn State University]

Today we are talking about the life -- and death -- of stars. Low mass stars live a long time, fusing all their hydrogen into helium over a trillion years. More massive stars like the Sun live shorter lives. They fuse hydrogen into helium, and eventually helium into carbon (and also some oxygen and neon). When this happens they expand, get brighter, and cool off, becoming red giants. They lose most of their mass, exposing their cores, and then cool off over many billions of years. Crash Course Astronomy posters now available at DFTBA: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents Low Mass Stars Live a Long Time 0:57 Larger Stars (Like Our Sun) Live Shorter Lives 3:10 Fueled By Fusion 3:58 How They Turn Into Red Giants 5:45 -- 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 Stars http://skycenter.arizona.edu/sites/skycenter.arizona.edu/files/n6522_32in.jpg [credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona] The Sizes of Stars http://www.eso.org/public/usa/images/eso1030c/ [credit: ESO/M. Kornmesser] Fusion in the Sun https://commons.wikimedia.org/wiki/File:FusionintheSun.svg [credit: Borb, Wikimedia Commons] Mega Flares http://scitechdaily.com/images/Swift-Mission-Observes-Mega-Flares-from-a-Mini-Star.jpg [credit: NASA’s Goddard Space Flight Center/S. Wiessinger] Proxima Centauri https://www.spacetelescope.org/images/potw1343a/ [credit: ESA/Hubble & NASA] Physics in the Core http://solarscience.msfc.nasa.gov/images/cutaway.jpg [credit: NASA / Marshall Space Flight Center] Three Years of SDO Images http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11255 [credit: NASA's Goddard Space Flight Center/SDO] Sun & Red Giants http://kepler.nasa.gov/files/mws/kasc3.jpg [credit: NASA] Sun as Red Giant https://commons.wikimedia.org/wiki/File:Sun_red_giant.svg [credit:Oona Räisänen, Wikimedia Commons] Gone with the Wind https://www.eso.org/public/usa/images/wr124/ [credit: ESO] Expanding & cooling https://www.cfa.harvard.edu/sites/www.cfa.harvard.edu/files/images/pr/2009-23/1/base.jpg [credit: ESO/L. Calçada] Looking down a barrel of gas at a doomed star http://hubblesite.org/newscenter/archive/releases/1999/01/image/a/ [credit: The Hubble Heritage Team (AURA/STScI/NASA)] Expanding star orbit http://www.nasa.gov/centers/goddard/images/content/415775main_earthlike-exoplanet-full.jpg [credit: SO/L. Calçada] Red Giant Earth https://commons.wikimedia.org/wiki/File:Red_Giant_Earth.jpg [credit: Fsgregs, Wikimedia Commons] Crab Nebula https://en.wikipedia.org/wiki/Crab_Nebula#/media/File:Crab_Nebula.jpg [credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)]

Today Phil follows up last week’s look at the death of low mass stars with what comes next: a white dwarf. White dwarfs are incredibly hot and dense objects roughly the size of Earth. They also can form planetary nebulae: huge, intricately detailed objects created when the wind blown from the dying stars is lit up by the central white dwarf. They only last a few millennia. The Sun probably won’t form one, but higher mass stars do. -- Table of Contents When low mass stars die they form white dwarfs 0:54 White dwarfs are roughly the size of Earth 2:16 Cloudy with a chance of Planetary Nebulae 3:59 Life Span 9:06 -- 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 Journey to the centre of the Sun http://www.spacetelescope.org/videos/astro_ac/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] Blowing Bubbles http://chandra.harvard.edu/resources/animations/pne.html [credit: (NASA/CXC/April Jubett)] Artist's impression of the sizes of Sirius B and the Earth http://www.spacetelescope.org/images/heic0516c/ [credit: ESA and NASA] The Dog Star, Sirius A, and its tiny companion http://www.spacetelescope.org/images/heic0516a/ [credit: NASA, ESA, H. Bond (STScI), and M. Barstow (University of Leicester)] The Spirograph Nebula https://www.spacetelescope.org/images/opo0028a/ [credit: NASA/ESA and The Hubble Heritage Team STScI/AURA] M27, NGC6853, Dumbbell Nebula https://www.noao.edu/image_gallery/html/im0688.html [credit: REU program/NOAO/AURA/NSF] Soap Bubble Nebula, PN G75.5+1.7 https://www.noao.edu/image_gallery/html/im1059.html [credit: T. A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN and NOAO/AURA/NSF] Hubble Sees Supersonic Exhaust From Nebula http://www.spacetelescope.org/images/opo9738a/ [credit: Bruce Balick (University of Washington), Vincent Icke (Leiden University, The Netherlands), Garrelt Mellema (Stockholm University), and NASA/ESA] Hubble snaps NGC 5189 http://www.spacetelescope.org/images/heic1220a/ [credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)] A dying star’s toxic legacy http://www.spacetelescope.org/images/potw1110a/ [credit: ESA/Hubble & NASA] Eskimo Nebula http://www.nasa.gov/multimedia/imagegallery/image_feature_762.html [credit: NASA/Andrew Fruchter (STScI)] Planetary nebula Abell 39 http://www.noao.edu/image_gallery/html/im0636.html [credit: WIYN/NOAO/NSF] The Butterfly Hunter http://chandra.harvard.edu/resources/animations/pne.html [credit: (NASA/CXC/April Jubett)] Red Giant Sun (video) http://www.spacetelescope.org/videos/hst15_red_giant_sun/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] The planetary nebula Abell 33 captured using ESO's Very Large Telescope https://commons.wikimedia.org/wiki/File:The_planetary_nebula_Abell_33_captured_using_ESO%27s_Very_Large_Telescope.jpg [credit: ESO, Wikimedia Commons] ESO's VLT images the planetary nebula IC 1295 http://www.eso.org/public/usa/images/eso1317a/ [credit: ESO] Looking Down a Barrel of Gas at a Doomed Star http://hubblesite.org/newscenter/archive/releases/1999/01/image/a/ [credit: The Hubble Heritage Team (AURA/STScI/NASA)]

Massive stars fuse heavier elements in their cores than lower mass stars. This leads to the creation of heavier elements up to iron. Iron robs critical energy from the core, causing it to collapse. The shock wave, together with a huge swarm of neutrinos, blast through the star’s outer layers, causing it to explode. The resulting supernova creates even more heavy elements, scattering them through space. Also, happily, we’re in no danger from a nearby supernova. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents Massive Stars Fuse Heavier Elements Up To Iron 1:15 Iron Uses High Amounts of Energy, Thus Making Stars Collapse 3:58 The Resulting Supernova Creates Even Heavier Elements 10:00 Relax, Something Else Will Kill You 9:04 -- 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 Blowing Bubbles http://chandra.harvard.edu/resources/animations/pne.html [credit: NASA/CXC/April Jubett] The Sizes of Stars http://www.eso.org/public/images/eso1030c/ [credit: ESO/M. Kornmesser] Red giants https://commons.wikimedia.org/wiki/File:Redgiants.svg [credit: Wikimedia Commons] Alpha Orionis http://imgsrc.hubblesite.org/hu/db/images/hs-1996-04-a-print.jpg [credit: A. Dupree (CfA), NASA, ESA] Sun and VY Canis Majoris https://commons.wikimedia.org/wiki/File:Sun_and_VY_Canis_Majoris.svg [credit: Wikimedia Commons] Witch Head Nebula and Rigel http://www.deepskycolors.com/archive/2009/11/16/witch-Head-Nebula-and-Rigel.html [credit: Rogelio Bernal Andreo] Layers of a massive star https://en.wikipedia.org/wiki/User:FT2/scc#/media/File:Massive_star_cutaway_pre-collapse_(pinned,_8M%2B).png [credit: Wikimedia Commons] NASA's Swift Reveals New Phenomenon in a Neutron Star http://www.nasa.gov/mission_pages/swift/bursts/new-phenom.html#.VcvAYflVhBd [credit: NASA's Goddard Space Flight Center] What is a black hole? http://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-a-black-hole-k4.html [credit: NASA/CXC/M.Weiss] The Death of Stars http://www.spacetelescope.org/videos/hubblecast52a/ [credit: ESA/Hubble] Giant Mosaic of the Crab Nebula http://www.nasa.gov/multimedia/imagegallery/image_feature_460.html [credit: NASA, ESA, J. Hester (Arizona State University)] Hubble and Chandra spot a celestial bauble http://www.spacetelescope.org/images/heic1018b/ [credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), and NASA/CXC/SAO/J. Hughes] Vela Supernova Remnant http://www.glitteringlights.com/Images/Nebulae/i-pqWFzmt/O [credit: Marco Lorenzi] Spica [credit: Phil Plait] Cassiopeia A https://en.wikipedia.org/wiki/Cassiopeia_A#/media/File:Cassiopeia_A_Spitzer_Crop.jpg [credit: Oliver Krause (Steward Observatory) George H. Rieke (Steward Observatory) Stephan M. Birkmann (Max-Planck-Institut fur Astronomie) Emeric Le Floc'h (Steward Observatory) Karl D. Gordon (Steward Observatory) Eiichi Egami (Steward Observatory) John Bieging (Steward Observatory) John P. Hughes (Rutgers University) Erick Young (Steward Observatory) Joannah L. Hinz (Steward Observatory) Sascha P. Quanz (Max-Planck-Institut fur Astronomie) Dean C. Hines (Space Science Institute)] Sloshing Supernova http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11735 [credit: NASA's Goddard Space Flight Center Video and images courtesy of NASA/JPL-Caltech] Star Burst http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11447 [credit: NASA's Goddard Space Flight Center Video courtesy of ESA/Hubble/L. Calcada]

In the aftermath of a 8 – 20 solar mass star’s demise we find a weird little object known as a neutron star. Neutrons stars are incredibly dense, spin rapidly, and have very strong magnetic fields. Some of them we see as pulsars, flashing in brightness as they spin. Neutrons stars with the strongest magnetic fields are called magnetars, and are capable of colossal bursts of energy that can be detected over vast distances. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents A Star Can Collapse to Form a Neutron Star 0:59 Neutron Star Characteristics 2:24 Pulsars 5:56 Magnetars 8:15 -- 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 Star Burst https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11447 [credit: NASA's Goddard Space Flight Center] X-ray Images of G292.0+1.8 http://chandra.harvard.edu/resources/animations/snr.html/?page=8 [credit: X-ray: NASA/CXC/Penn State/S.Park et al.; Optical: Pal.Obs. DSS] Neutron star cross section https://commons.wikimedia.org/wiki/File:Neutron_star_cross_section.jpg [credit: NASA] Fermi Spots 'Superflares' in the Crab Nebula https://www.youtube.com/watch?v=qDhdwgK218E [credit: NASA/Goddard Space Flight Center] What is a pulsar? https://www.youtube.com/watch?v=gjLk_72V9Bw [credit: NASA's Goddard Space Flight Center] Jocelyn Bell http://blog.sciencemuseum.org.uk/insight/2013/03/20/1960-discovery-of-pulsars/ [credit: National Media Museum / Science & Society Picture Library] Beacons of X-ray Light https://www.youtube.com/watch?v=6p2OGc6a_TQ [credit: NASA/JPL-Caltech] Chandra Time-Lapse Movie http://chandra.harvard.edu/photo/2002/0052/animations.html [credit: NASA/CXC/ASU/J.Hester et al.] NASA's Fermi Satellite Finds Hints of Starquakes in Magnetar 'Storm' http://www.nasa.gov/content/goddard/nasas-fermi-satellite-finds-hints-of-starquakes-in-magnetar-storm [credit: NASA's Goddard Space Flight Center/S. Wiessinger] NASA's Swift Reveals New Phenomenon in a Neutron Star http://www.nasa.gov/mission_pages/swift/bursts/new-phenom.html#.Vcp-6flVhBe [credit: NASA's Goddard Space Flight Center] Cosmic Explosion Second Only to the Sun in Brightness https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=20077 [credit: NASA/Goddard Space Flight Center Conceptual Image Lab]

We’ve covered a lot of incredible stuff, but this week we’re talking about the weirdest objects in space: BLACK HOLES. Stellar mass black holes form when a very massive star dies, and its core collapses. The core has to be more than about 2.8 times the Sun’s mass to form a black hole. Black holes come in different sizes, but for all of them, the escape velocity is greater than the speed of light, so nothing can escape, not matter or light. They don’t wander the Universe gobbling everything down around them; their gravity is only really intense very close to them. Tides near a stellar mass black hole will spaghettify you, and time slows down when you get near a black hole — not that this helps much if you’re falling in. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents How Stellar Mass Black Holes Are Formed 1:03 The Core 1:43 Nothing Can Escape Once It’s Inside 2:29 Gravity Intensifies The Closer You Get 3:33 Spaghettification 6:01 Time Will Slow Down Near A Black Hole 8:01 -- 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 White Dwarf Pulses Like a Pulsar http://www.nasa.gov/centers/goddard/news/topstory/2007/whitedwarf_pulsar.html [credit: NASA, Casey Reed] Swift Reveals New Phenomenon in a Neutron Star http://www.nasa.gov/mission_pages/swift/bursts/new-phenom.html#.Vc4isflVhBd [credit: NASA's Goddard Space Flight Center] Black Holes - Monsters in Space https://en.wikipedia.org/wiki/File:Black_Holes_-_Monsters_in_Space.jpg [credit: NASA/JPL-Caltech, Wikimedia Commons] What if the Sun became a black hole? (artist's impression) http://www.spacetelescope.org/videos/hubblecast43g/ [credit: ESA/Hubble (M. Kornmesser)] Black Hole Animation http://chandra.harvard.edu/photo/2003/0203long/animations.html [credit: NASA/SAO/CXC/D.Berry] Star Destroyer http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11065 [credit: Space Telescope Science Institute (STScI) and NASA's Goddard Space Flight Center] Black hole deforms space http://www.spacetelescope.org/videos/hst15_blackhole_grid/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] Black hole close-up (artist's impression) http://www.spacetelescope.org/videos/heic0211c/ [credit: European Space Agency, NASA and Felix Mirabel (the French Atomic Energy Commission & the Institute for Astronomy and Space Physics/Conicet of Argentina)]

Double stars are stars that appear to be near each other in the sky, but if they’re gravitationally bound together we call them binary stars. Many stars are actually part of binary or multiple systems. If they are close enough together they can actually touch other, merging into one peanut-shaped star. In some close binaries matter can flow from one star to the other, changing the way it ages. If one star is a white dwarf, this can cause periodic explosions, and possibly even lead to blowing up the entire star. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents What are binary stars? 0:51 Merging peanut-shaped stars 6:52 Close binaries begin to flow into one another, sometimes blowing up the star 8:29 -- 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 Big Dipper http://www.deepskycolors.com/archive/2011/05/14/The-Big-Dipper.html [credit: Rogelio Bernal Andreo] Sirius https://www.spacetelescope.org/images/heic0516a/ [credit: NASA, ESA, H. Bond (STScI), and M. Barstow (University of Leicester)] Sirius A and B http://chandra.harvard.edu/photo/2000/0065/index.html [credit: NASA/SAO/CXC] Clashing Winds (video) http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11680 [credit: NASA's Goddard Space Flight Center] The Radial Velocity Method (artist’s impression) http://www.eso.org/public/images/eso0722e/ [credit: ESO] Mizar+Alcor https://commons.wikimedia.org/wiki/File:Thomas_Bresson_-_Mizar%2Balcor_(by).jpg [credit: Wikimedia Commons, Thomas Bresson] Polaris http://imgsrc.hubblesite.org/hu/db/images/hs-2006-02-e-print.jpg [credit: NASA, ESA, and G. Bacon] Does the Sun Have Long Lost Siblings? https://www.youtube.com/watch?v=IaWg2ACMspk [credit: SciShow Space] Clashing Winds (image) http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11680 [credit: NASA/C. Reed X-ray images courtesy of NASA/GSFC/S. Immler] Artist’s impression of the pulsar PSR J0348+0432 and its white dwarf companion http://www.eso.org/public/images/eso1319c/ [credit: ESO/L. Calçada] Artist’s impression of eclipsing binary http://www.eso.org/public/videos/eso1311b/ [credit: ESO/L. Calçada] Artist’s impression of the yellow hypergiant star HR 5171 http://www.eso.org/public/images/eso1409b/ [credit: ESO] Nova http://www.nasa.gov/centers/goddard/news/topstory/2008/keck_ophiuchi_prt.htm [credit: NASA, Casey Reed] Artist's impression of RS Ophiuchi http://www.jodrellbank.manchester.ac.uk/news/2006/rsoph-radio/ [credit: David A. Hardy/http://www.astroart.org & PPARC] An artist's impression of Sirius A and B http://www.spacetelescope.org/images/heic0516b/ [credit: NASA, ESA and G. Bacon (STScI)] Artist's impression of vampire star http://www.spacetelescope.org/videos/astro_bn/ [credit: ESO/M. Kornmesser] Type Ia supernova http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10532 [credit: Walt Feimer, NASA/Goddard Space Flight Center]

Last week we covered multiple star systems, but what if we added thousands or even millions of stars to the mix? A star cluster. There are different kinds of clusters, though. Open clusters contain hundreds or thousands of stars held together by gravity. They’re young, and evaporate over time, their stars let loose to roam space freely. Globular clusters, on the other hand, are larger, have hundreds of thousands of stars, and are more spherical. They’re very old, a significant fraction of the age of the Universe itself, and that means their stars have less heavy elements in them, are redder, and probably don’t have planets (though we’re not really sure). Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents Open clusters contain hundreds or thousands of young stars 00:29 Over time, open clusters evaporate 3:23 Globular clusters contain hundreds of thousands of old stars in spherical formation 5:50 Globular clusters have less heavy elements, thus probably do not have planets 6:43 -- 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 Magellanic gemstone in the southern sky [NGC 290] http://www.spacetelescope.org/images/heic0603c/ [credit: European Space Agency & NASA] Extreme star cluster bursts into life in new Hubble image http://www.spacetelescope.org/images/heic0715a/ [credit: NASA, ESA and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration] View of a Sun-like star within an open cluster (artist’s impression) http://www.spacetelescope.org/videos/heic1321d/ [credit: NASA, ESA, and M. Kornmesser] Motion of stars in Omega Centauri http://www.spacetelescope.org/videos/heic1017a/ [credit: NASA, ESA, J. Anderson and R. van der Marel (STScI)] 47 Tucanae: Probing Extreme Matter Through Observations of Neutron Stars http://chandra.harvard.edu/photo/2013/47tuc/ [credit: NASA/CXC/Michigan State/A.Steiner et al] Hubble Refines Distance to Pleiades Star Cluster http://hubblesite.org/newscenter/archive/releases/2004/20/image/a/ [credit: NASA, ESA and AURA/Caltech] M45 Pleiades https://www.noao.edu/image_gallery/html/im1116.html [credit: T.A. Rector (University of Alaska Anchorage), Richard Cool (University of Arizona) and WIYN] From the Pleiades to the Hyades http://www.deepskycolors.com/archive/2011/11/06/from-the-Pleiades-to-the-Hyades.html [credit: Rogelio Bernal Andreo] Messier 035 Atlas Image https://commons.wikimedia.org/wiki/File:Messier_035_2MASS.jpg [credit: Two Micron All Sky Survey (2MASS), a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation] Globular cluster 47 Tucanae http://www.spacetelescope.org/images/heic1510a/ [credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration] The oldest cluster in its cloud http://www.spacetelescope.org/images/potw1428a/ [credit: ESA/Hubble & NASA] An unexpected population of young-looking stars http://www.spacetelescope.org/images/potw1244a/ [credit: ESA/Hubble & NASA] View of a globular cluster (artist’s impression) http://www.spacetelescope.org/videos/heic1321c/ [credit: NASA, ESA, and M. Kornmesser] All that glitters http://www.spacetelescope.org/images/potw1449a/ [credit: ESA/Hubble & NASA]

Astronomers study a lot of gorgeous things, but nebulae might be the most breathtakingly beautiful of them all. Nebulae are clouds of gas and dust in space. They can glow on their own or reflect light from nearby stars. When they glow it’s usually predominantly red from hydrogen and green from oxygen, and when they reflect and scatter light it’s from massive hot stars, so they look blue. Stars are born in some nebulae, and create new ones as they die. Some nebulae are small and dense, others can be dozens or hundreds of light years across. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents Nebulae Are Clouds of Gas And/Or Dust 0:42 They Can Emit Light Or Reflect It 1:20 Elements Change Their Glow 3:31 Nebulae Can Create Stars 5:28 -- 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 Saturn https://www.flickr.com/photos/badastronomy/10328043663/sizes/o/in/photostream/ [credit: Photo by NASA / JPL / Space Science Institute / Gordan Ugarkovic] Carina Nebula http://www.spacetelescope.org/news/heic0707/ [credit: NASA, ESA, N. Smith (University of California, Berkeley), and The Hubble Heritage Team (STScI/AURA)] Crab Nebula http://sci.esa.int/herschel/53338-herschel-and-hubble-composite-image-of-the-crab-nebula/ [credit: ESA/Herschel/PACS/MESS Key Programme Supernova Remnant Team; NASA, ESA and Allison Loll/Jeff Hester (Arizona State University)] Carina Jets http://www.spacetelescope.org/images/heic1007a/ [credit: NASA, ESA, M. Livio and the Hubble 20th Anniversary Team (STScI)] The Twin Jet Nebula http://www.spacetelescope.org/images/heic1518a/ [credit: ESA/Hubble & NASA] Tycho's Supernova Remnant http://chandra.harvard.edu/photo/2011/tycho/ [credit: X-ray: NASA/CXC/Rutgers/K.Eriksen et al.; Optical: DSS] Ring Nebula's True Shape http://hubblesite.org/newscenter/archive/releases/2013/13/image/a/ [credit: NASA, ESA, C.R. O'Dell (Vanderbilt University), and D. Thompson (Large Binocular Telescope Observatory)] 3D animation of the Orion nebula http://www.spacetelescope.org/videos/astro_bo/ [credit: ESO/M. Kornmesser] Stardust http://stardust.jpl.nasa.gov/images/science/idp-m.jpg [credit: NASA] From the Pleiades to the Hyades http://www.deepskycolors.com/archive/2011/11/06/from-the-Pleiades-to-the-Hyades.html [credit: Rogelio Bernal Andreo] How to Become a Star http://www.eso.org/public/images/eso0102a/ [credit: ESO] The Orion Nebula http://www.eso.org/public/images/eso1103a/ [credit: ESO/Igor Chekalin] Trapezium Cluster in the Orion Nebula http://www.spacetelescope.org/images/opo0019b/ [credit: K.L. Luhman (Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.); and G. Schneider, E. Young, G. Rieke, A. Cotera, H. Chen, M. Rieke, R. Thompson (Steward Observatory, University of Arizona, Tucson, Ariz.) and NASA/ESA] PIA08656 http://www.jpl.nasa.gov/spaceimages/images/largesize/PIA08656_hires.jpg [credit: NASA/JPL-Caltech/IRAS/H. McCallon] Edge-On Protoplanetary Disc in the Orion Nebula http://www.spacetelescope.org/images/opo9545h/ [credit: Mark McCaughrean (Max-Planck-Institute for Astronomy), C. Robert O'Dell (Rice University), and NASA/ESA] Hubble's sharpest image of the Orion Nebula with proplyd highlights https://www.spacetelescope.org/images/heic0917ab/ [credit: NASA, ESA, M. Robberto (Space Telescope Science Institute/ESA), the Hubble Space Telescope Orion Treasury Project Team and L. Ricci (ESO)] Young Stellar Disks in Infrared http://www.spacetelescope.org/images/opo9905b/ [credit: D. Padgett (IPAC/Caltech), W. Brandner (IPAC), K. Stapelfeldt (JPL) and NASA/ESA] The Eagle Nebula, M16 https://www.noao.edu/image_gallery/html/im0725.html [credit: T.A.Rector (NRAO/AUI/NSF and NOAO/AURA/NSF) and B.A.Wolpa (NOAO/AURA/NSF)] Pillars of Creation http://hubblesite.org/newscenter/archive/releases/2015/01/image/e/warn/ [credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)] Planetary Nebula HFG1 https://www.noao.edu/image_gallery/html/im1110.html [credit: T.A. Rector (University of Alaska Anchorage) and H. Schweiker (WIYN and NOAO/AURA/NSF)] Zooming in on the Horsehead Nebula http://www.spacetelescope.org/videos/heic1307c/ [credit: NASA, ESA, and G. Bacon (STScI); ESO] Orion, from Head to Toes http://www.deepskycolors.com/archive/2010/10/22/orion-from-Head-to-Toes.html [credit: Rogelio Andreo Bernal] Sifting through Dust near Orion’s Belt (mouseover comparison) http://www.eso.org/public/images/comparisons/eso1219a/ [credit: ESO/APEX (MPIfR/ESO/OSO)/T. Stanke et al./Igor Chekalin/Digitized Sky Survey 2]

Today we’re talking about our galactic neighborhood: The Milky Way. It’s a disk galaxy, a collection of dust, gas, and hundreds of billions of stars, with the Sun located about halfway out from the center. The disk has grand spiral patterns in it, formed by the traffic jams of stars and nebulae, where stars are born. The central region is shaped like a bar, and is mostly old, red stars. There’s also a halo surrounding us of old stars. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents Milky Way Is A Disc 2:54 Grand Spiral Patterns 4:21 The Central Region Is Bar Shaped 7:48 Outer Halo Of Old Stars 9:09 -- 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 Milky Way, Artist’s Drawing http://www.nasa.gov/mission_pages/spitzer/multimedia/20080603a.html [credit: NASA/JPL-Caltech] Joshua Tree http://deepskycolors.com/astro/2013/04/2013-04_JoshuaTree_MW.jpg [credit: Rogelio Bernal Andreo] Milky Way Center Region Mosaic http://sguisard.astrosurf.com/Pagim/GC.html [credit: ESO] New Hubble image of star cluster Messier 15 http://www.spacetelescope.org/images/heic1321a/ [credit: NASA, ESA] Artist’s impression of the Milky Way http://www.spacetelescope.org/videos/hubblecast70b/ [credit: ESA/Hubble and M. Kornmesser] M83 (Hubble Only and Hubble-Subaru-ESO Composite) http://www.robgendlerastropics.com/M83-New-HST.html [credit: Robert Gendler, 8.2 Meter Subaru Telescope (NAOJ), European Southern Observatories, Hubble Legacy Archive] Hubble's Largest Galaxy Portrait Offers a New High-Definition View http://hubblesite.org/newscenter/archive/releases/2006/10/image/a/ [credit: NASA, ESA, K. Kuntz (JHU), F. Bresolin (University of Hawaii), J. Trauger (Jet Propulsion Lab), J. Mould (NOAO), Y.-H. Chu (University of Illinois, Urbana), and STScI] NGC 3344 http://skycenter.arizona.edu/gallery/Galaxies/NGC3344 [credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona] Annotated Milky Way http://www.jpl.nasa.gov/images/wise/20150603/spitzer20150603.jpg [credit: NASA/JPL-Caltech] Black hole with corona, X-ray source (artist's concept) https://en.wikipedia.org/wiki/Black_hole#/media/File:Black_Holes_-_Monsters_in_Space.jpg [credit: NASA/JPL-Caltech] A Galaxy and its Halo http://www.esa.int/spaceinimages/Images/2008/06/A_galaxy_and_its_halo [credit: ESA (image by C. Carreau)] How to Become a Star http://www.eso.org/public/images/eso0102a/ [credit: ESO]

The Milky Way is our neighborhood in the universe. It’s a galaxy and there are many others out there. Galaxies contain gas, dust, and billions of stars or more. They come in four main shapes: elliptical, spiral, peculiar, and irregular. Galaxies can collide, and grow in size by eating each other. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents Milky Way is a Galaxy (One of Many) 2:04 Galaxies Have Four Main Shapes 3:18 Galaxies Can Collide 6:05 -- 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 NGC 5363 http://aftar.uaa.alaska.edu/gallery/details.cfm?img=316&type=# [credit: T.A. Rector (University of Alaska Anchorage) and H. Schweiker (WIYN and NOAO/AURA/NSF)] Panorama of Spiral Galaxy, M31 http://www.noao.edu/image_gallery/html/im1259.html [credit: Local Group Survey Team and T.A. Rector (University of Alaska Anchorage)] Animation of a variable star http://www.spacetelescope.org/videos/heic1323j/ [credit: NASA, ESA, M. Kornmesser] Hubble M31 PHAT Mosaic http://hubblesite.org/newscenter/archive/releases/2015/02/image/a/ [credit: NASA, ESA, J. Dalcanton, B.F. Williams, and L.C. Johnson (University of Washington), the PHAT team, and R. Gendler] Elliptical - Death of giant galaxies spreads from the core https://www.spacetelescope.org/news/heic1508/ [credit: ESA/Hubble & NASA] Spiral - HUBBLE VIEW OF BARRED SPIRAL GALAXY MESSIER 83 http://sci.esa.int/hubble/53590-hubble-view-of-barred-spiral-galaxy-messier-83/ [credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA). Acknowledgement: William Blair (Johns Hopkins University)] Peculiar - Colliding galaxies make love, not war https://www.spacetelescope.org/news/heic0615/ [credit: NASA, ESA, and the Hubble Heritage Team STScI/AURA)-ESA/Hubble Collaboration] Irregular - Little Galaxy Explored http://www.nasa.gov/mission_pages/spitzer/multimedia/asmccaption_prt.htm [credit: NASA/JPL-Caltech/STScI] Hubble Image of Messier 101 http://hubblesite.org/newscenter/archive/releases/2009/07/image/h/ [credit: NASA, ESA, K. Kuntz (JHU), F. Bresolin (University of Hawaii), J. Trauger (Jet Propulsion Lab), J. Mould (NOAO), Y.-H. Chu (University of Illinois, Urbana), and STScI] A poster-size image of the beautiful barred spiral galaxy NGC 1300 http://www.spacetelescope.org/images/opo0501a/ [credit: NASA, ESA, and The Hubble Heritage Team STScI/AURA)] NGC 3344 http://skycenter.arizona.edu/gallery/Galaxies/NGC3344 [credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona] Flocculent spiral NGC 2841 http://www.spacetelescope.org/news/heic1104/ [credit: NASA, ESA and the Hubble Heritage Team] Barred Spiral Galaxy NGC1365 https://www.noao.edu/image_gallery/html/im1034.html [credit: SSRO/PROMPT and NOAO/AURA/NSF] Magnificent Details in a Dusty Spiral Galaxy http://hubblesite.org/newscenter/archive/releases/1999/25/image/a/ [credit: The Hubble Heritage Team] Panning across Messier 77 http://www.spacetelescope.org/videos/heic1305b/ [credit: NASA, ESA, Digitized Sky Survey 2. Acknowledgement: A. van der Hoeven] Hubble Mosaic of the Sombrero Galaxy http://www.spacetelescope.org/images/opo0328a/ [credit: NASA/ESA and The Hubble Heritage Team] Spiral Galaxy NGC 4565 http://www.eso.org/public/images/eso0525a/ [credit: ESO] M87 (with Jet) http://skycenter.arizona.edu/gallery/Galaxies/M87%28withJet%29 [credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona] M59, NGC4621 https://www.noao.edu/image_gallery/html/im0579.html [credit: NOAO/AURA/NSF] Fulldome simulation of colliding galaxies http://www.spacetelescope.org/videos/gal_coll_dome_3800/ [credit: NASA/STScI] Antennae Galaxies http://www.spacetelescope.org/images/potw1345a/ [credit: ESA/Hubble & NASA] Terzan 5 Artist’s Concept http://www.sdss3.org/press/images/20111130.fourtails.streams-3.jpg [credit: Amanda Smith, Institute of Astronomy, University of Cambridge] Interacting Galaxy Pair Arp 87 http://hubblesite.org/newscenter/archive/releases/2007/36/image/a/ [credit: NASA, ESA, and the Hubble Heritage Team] Doing cartwheels to celebrate the end of an era http://www.spacetelescope.org/images/potw1036a/ [credit: ESA/Hubble & NASA] Hoag's Object http://hubblesite.org/newscenter/archive/releases/2002/21/image/a/ [credit: NASA and The Hubble Heritage Team] Paranal Nights https://www.eso.org/public/images/potw1401a/ [credit: Y. Beletsky (LCO)/ESO] Tarantula Nebula http://www.eso.org/public/images/eso1023a/ [credit: TRAPPIST/E. Jehin/ESO] Hubble Ultra Deep Field 2014 http://hubblesite.org/newscenter/archive/releases/2014/27/image/a/ [credit: NASA, ESA]

Active galaxies pour out lots of energy, due to their central supermassive black holes gobbling down matter. Galaxies tend not to be loners, but instead exist in smaller groups and larger clusters. Our Milky Way is part of the Local Group, and will one day collide with the Andromeda galaxy. Clusters of galaxies also clump together to form superclusters, the largest structures in the Universe. In total, there are hundreds of billions of galaxies in the Universe. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents Black Holes at the Center of Galaxies 2:26 Galaxies Are a Part of Small/Large Clusters 9:47 The Milky Way is Part of the Local Group 6:45 Galaxy Clusters Clump Together to Create Superclusters 11:03 Hundreds of Billions of Galaxies 12:39 -- 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 Galactic Wreckage in Stephan's Quintet http://hubblesite.org/newscenter/archive/releases/2009/25/image/x/ [credit: NASA, ESA, and the Hubble SM4 ERO Team] Best image of bright quasar 3C 273 http://www.spacetelescope.org/images/potw1346a/ [credit: ESA/Hubble & NASA] Nearby Quasar 3C 273 http://hubblesite.org/newscenter/archive/releases/2003/03/image/a/ [credit: NASA, M. Clampin (STScI), H. Ford (JHU), G. Illingworth (UCO/Lick Observatory), J. Krist (STScI), D. Ardila (JHU), D. Golimowski (JHU), the ACS Science Team, J. Bahcall (IAS) and ESA] Gamma Rays http://chandra.harvard.edu/photo/2014/archives/archives_herca.jpg [credit: X-ray: NASA/CXC/SAO, Optical: NASA/STScI, Radio: NSF/NRAO/VLA] Black hole (artist's impression) http://www.spacetelescope.org/videos/hst15_black_hole2/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] Matter accreting around a supermassive black hole (artist's impression) http://www.spacetelescope.org/videos/hubblecast43c/ [credit: ESA/Hubble (M. Kornmesser)] Artist’s animation of galaxy with jets from a supermassive black hole http://www.spacetelescope.org/videos/heic1511a/ [credit: ESA/Hubble, L. Calçada (ESO)] NASA's Swift Finds 'Missing' Active Galaxies https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10698 [credit: NASA/Goddard Space Flight Center] Sagittarius A*: NASA's Chandra Detects Record-Breaking Outburst from Milky Way's Black Hole http://chandra.harvard.edu/photo/2015/sgra/ [credit: NASA/CXC/Amherst College/D.Haggard et al] NASA Hubble Sees Sparring Antennae Galaxies https://www.nasa.gov/content/goddard/nasa-hubble-sees-sparring-antennae-galaxies [credit: Hubble/European Space Agency] A New Dawn http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11011 [credit: NASA, ESA, G. Besla (Columbia University) and R. van der Marel (STScI)] Galaxy Sky http://svs.gsfc.nasa.gov/vis/a010000/a011000/a011011/hs-2012-20-h-full_1920x1080.jpg [credit: NASA, ESA, Z. Levay and R. van der Marel (STScI) T. Hallas, and A. Mellinger] Virgo Cluster http://deepskycolors.com/astro/2015/06/RBA_VirgoCluster3p_2048.jpg [credit: Rogelio Bernal Andreo] Cosmic Clumps http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11445 [credit: NASA's Scientific Visualization Studio] Laniakea: Our Home Supercluster of Galaxies http://apod.nasa.gov/apod/ap140910.html [credit: R. Brent Tully (U. Hawaii) et al., SDvision, DP, CEA/Saclay] Webb Science Simulations http://svs.gsfc.nasa.gov/vis/a010000/a010600/a010663/index.html [credit: NASA/Goddard Space Flight Center and the Advanced Visualization Laboratoy at the National Center for Supercomputing Applications] Hubble Deep Field https://upload.wikimedia.org/wikipedia/commons/5/5f/HubbleDeepField.800px.jpg [credit: R. Williams (STScI), the Hubble Deep Field Team and NASA] Hubble Ultra Deep Field 2014 http://hubblesite.org/newscenter/archive/releases/2014/27/image/a/ [credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)]

Gamma-ray bursts are not only incredible to study, but their discovery has an epic story all its own. Today Phil takes you through some Cold War history and then dives into what we know. Bursts come in two rough varieties: Long and short. Long ones are from hypernovae, massive stars exploding, sending out twin beams of matter and energy. Short ones are from merging neutron stars. Both kinds are so energetic they are visible for billions of light years, and both are also the birth announcements of black holes. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents Gamma-Ray Were Discovered During the Cold War 0:47 Bursts Come in Two Varieties: Long and Short 8:35 Long Bursts Are From Hypernovae, Massive Stars Exploding 6:46 Short Ones Are From Merging Neutron Stars 9:00 Both Are The Birthplace of Black holes 9:55 -- 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 Nuclear Bomb Images via Wikimedia Commons: Operation Upshot Knothole https://en.wikipedia.org/wiki/File:Operation_Upshot-Knothole_-_Badger_001.jpg Ivy Mike https://en.wikipedia.org/wiki/File:IvyMike2.jpg Castle Bravo https://en.wikipedia.org/wiki/Castle_Bravo#/media/File:Castle_Bravo_Blast.jpg Upshot Knothole GRABLE https://en.wikipedia.org/wiki/File:Upshot-Knothole_GRABLE.jpg President Kennedy signs the Limited Nuclear Test Ban Treaty https://en.wikipedia.org/wiki/Partial_Nuclear_Test_Ban_Treaty#/media/File:President_Kennedy_signs_Nuclear_Test_Ban_Treaty,_07_October_1963.jpg [credit: Wikimedia Commons] Vela http://www.losangeles.af.mil/shared/media/photodb/photos/2013/06/130605-F-IN001-011.jpg [credit: USAF] The Crab Nebula https://www.nasa.gov/multimedia/imagegallery/image_feature_1604.html [credit: NASA, ESA, J. Hester, A. Loll (ASU)] Solar Flare http://www.nasa.gov/mission_pages/sunearth/news/News041612-M1.7flare.html [credit: NASA/SDO/AIA] Gamma Ray Burst http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=20139 [credit: NASA/Goddard Space Flight Center Conceptual Image Lab] Four ALMA antennas on the Chajnantor plain http://www.eso.org/public/images/alma-jfs-2010-10/ [credit: ESO/José Francisco Salgado (josefrancisco.org)] Gamma Ray Burst 970228 https://www.spacetelescope.org/images/opo9730b/ [credit: Andrew Fruchter (STScI), Elena Pian (ITSRE-CNR), and NASA/ESA] HST/STIS Image of the optical afterglow of w:GRB 970508 https://en.wikipedia.org/wiki/GRB_970508#/media/File:StisI.gif [credit: STScI/NASA] Black Holes: Monsters in Space http://www.nasa.gov/mission_pages/nustar/multimedia/pia16695.html [credit: NASA/JPL-Caltech] Naked-Eye Gamma-ray Burst Model for GRB 080319B http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10369 [credit: NASA/Swift/Cruz deWilde] 2008 GRB http://www.nasa.gov/images/content/218810main_grb_20080320_HI.jpg [credit: NASA/Swift/Stefan Immler, et al.] GRB Data http://www.nasa.gov/images/content/134782main_GRB_data_compare_black_sm.jpg [credit: NASA] Imagine two massive stars born together as a binary star http://chandra.harvard.edu/photo/2005/j0806/wd_lg.mpg [credit: NASA/GSFC/D. Berry] Colliding Binary Neutron stars http://chandra.harvard.edu/resources/animations/neutronstars.html?page=4 [credit: NASA/D.Berry] Black Hole Devours a Neutron Star http://chandra.harvard.edu/resources/animations/neutronstars.html?page=5 [credit: NASA/D.Berry] Eta Carinae https://en.wikipedia.org/wiki/Eta_Carinae#/media/File:Eta_Carinae.jpg [credit: Jon Morse (University of Colorado) & NASA Hubble Space Telescope] WR 104: A Pinwheel Star System http://apod.nasa.gov/apod/ap140603.html [credit: P. Tuthill (U. Sydney) & J. Monnier (U. Michigan), Keck Obs., ARC, NSF] Swift HD Beauty Shot http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10867 [credit: NASA/Goddard Space Flight Center] Swift's 500 Gamma-ray Bursts http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10590 [credit: NASA/Goddard Space Flight Center]

Today on Crash Course Astronomy, Phil dives into some very dark matters. The stuff we can actually observe in the universe isn’t all there is. Galaxies and other large structures in the universe are created and shifted by a force we detect mostly indirectly, by observing its impact: DARK MATTER. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents Normal and Dark Matter 0:55 Dark Matter Only Interacts With Normal Matter Through Gravity 4:27 Dark Matter Bends Light 5:08 -- 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 Virtual tour in our Solar System (Artist's impression) http://www.spacetelescope.org/videos/hubblecast27b/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] Hubblecast 11: A grand design in a galactic festoon http://www.spacetelescope.org/videos/heic0719a/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] Hubble's High-Definition Panoramic View of the Andromeda Galaxy http://hubblesite.org/newscenter/archive/releases/2015/02/image/a/ [credit: NASA, ESA, J. Dalcanton, B.F. Williams, and L.C. Johnson (University of Washington), the PHAT team, and R. Gendler] Panning and zooming on Abell 1689 http://www.spacetelescope.org/videos/heic0805b/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] All-sky image of molecular gas and three molecular cloud complexes seen by Planck http://www.nasa.gov/mission_pages/planck/multimedia/pia15227.html#.ViZwA36rSUl [credit: ESA/Planck Collaboration] How to Become a Star http://www.eso.org/public/images/eso0102a/ [credit: ESO] Neutron star illustrated https://commons.wikimedia.org/wiki/File:Neutron_star_illustrated.jpg [credit: NASA, Casey Reed - Penn State University] Alone in Space - Astronomers Find New Kind of Planet http://www.nasa.gov/topics/universe/features/pia14093.html [credit: NASA/JPL-Caltech] Black hole deforms space http://www.spacetelescope.org/videos/hst15_blackhole_grid/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] Gravitational lensing in action http://www.spacetelescope.org/videos/heic1106a/ [credit: NASA, ESA & L. Calçada] Bullet Cluster http://apod.nasa.gov/apod/image/0608/bulletcluster_comp_f2048.jpg [credit: X-ray: NASA/CXC/CfA/ M.Markevitch et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/ D.Clowe et al. Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.] Bullet Cluster, Optical http://chandra.harvard.edu/photo/2008/bullet/bullet_optical.jpg [credit: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.] Bullet Cluster, X-ray http://chandra.harvard.edu/photo/2008/bullet/bullet_xray.jpg [credit: NASA/CXC/CfA/ M.Markevitch et al.] The Bullet Cluster http://www.esa.int/spaceinimages/Images/2007/07/The_Bullet_Cluster2 [credit: X-ray: NASA/CXC/CfA/M.Markevitch, Optical and lensing map: NASA/STScI, Magellan/U.Arizona/D.Clowe, Lensing map: ESO WFI] Pandora’s Cluster — Clash of the Titans http://www.nasa.gov/mission_pages/hubble/science/pandora-cluster.html [credit: NASA] Hubble Refines Distance to Pleiades Star Cluster http://hubblesite.org/newscenter/archive/releases/2004/20/image/a/ [credit: NASA, ESA and AURA/Caltech] Stephan’s Quintet http://apod.nasa.gov/apod/ap120225.html [credit: Hubble Legacy Archive, ESA, NASA] Virgo Cluster Galaxies http://apod.nasa.gov/apod/ap150804.html [credit: Rogelio Bernal Andreo] Illustration of the distribution dark matter in the Universe http://www.nasa.gov/mission_pages/hubble/science/hst_img_20080520.html [credit: NASA, ESA, and E. Hallman (University of Colorado, Boulder)]

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: http://store.dftba.com/products/crashcourse-astronomy-poster -- 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 -- 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 Data System] Andromeda http://www.nasa.gov/images/content/386910main_M31_optical_wide.jpg [credit: Bill Schoening, Vanessa Harvey/REU program/NOAO/AURA/NSF] The Big Bang (video) http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10128 [credit: NASA] The Sun https://www.nasa.gov/sites/default/files/706436main_20121114-304-193blend_m6-orig_full.jpg [credit: NASA/SDO] Alpha Centauri http://www.eso.org/public/images/eso1241e/ [credit: ESO/Digitized Sky Survey 2, Acknowledgement: Davide De Martin] Andromeda https://en.wikipedia.org/wiki/Andromeda_Galaxy#/media/File:Andromeda_galaxy_2.jpg [credit: NASA/JPL-Caltech] Friedmann Universes https://commons.wikimedia.org/wiki/File:Friedmann_universes.svg Friedmann Equation http://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. https://en.wikipedia.org/wiki/Arno_Allan_Penzias#/media/File:Horn_Antenna-in_Holmdel,_New_Jersey.jpeg [credit: NASA] Planck CMB http://www.esa.int/spaceinimages/Images/2013/03/Planck_CMB [credit: ESA and the Planck Collaboration] Galaxy Superclusters http://irfu.cea.fr/Projets/coast_documents/images_MareNostrum/SDvision-MN00097-hires-01-mymix-a0_075.jpg [credit: Marenostrum Numerical Cosmology Project]

The majority of the universe is made up of a currently mysterious entity that pervades space: dark energy. We don’t know exactly what it is, but we do know that dark energy accelerates the expansion of space. We think this means the Universe will expand forever, even as our view of it shrinks while space expands faster all the time. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- GEOMETRY OF THE UNIVERSE RESOURCES Geometry: http://abyss.uoregon.edu/~js/cosmo/lectures/lec15.html http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question35.html Expanding faster than light: http://curious.astro.cornell.edu/legal-information/104-the-universe/cosmology-and-the-big-bang/expansion-of-the-universe/616-is-the-universe-expanding-faster-than-the-speed-of-light-intermediate General expansion: https://en.wikipedia.org/wiki/Metric_expansion_of_space -- Table of Contents Majority of the Universe is Made of Dark Energy 4:35 Dark Energy Accelerates the Expansion of Space 3:42 We Think The Universe Will Expand Forever 5:20 -- 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 The Big Bang http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10128 [credit: NASA] Collision Scenario for Milky Way and Andromeda Galaxy Encounter http://www.nasa.gov/images/content/654284main_i1220bw.jpg [credit: NASA; ESA; A. Feild and R. van der Marel, STScI] Artist's impression of vampire star http://www.spacetelescope.org/videos/astro_bn/ [credit: ESO/M. Kornmesser] Host Galaxies of Distant Supernovae http://www.nasa.gov/sites/default/files/images/593872main_hs-2006-52-a-print.jpg [credit: NASA, ESA, and A. Riess (STScl)] Dark Energy Expands the Universe http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10135 [credit: NASA] Expanding Universe http://www.spacetelescope.org/videos/hst15_expanding_universe/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] Hubble Ultra Deep Field 2014 http://hubblesite.org/newscenter/archive/releases/2014/27/image/a/ [credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)]

Thanks to the wonders of physics, astronomers can map a timeline of the universe’s history. Today, Phil’s going to give you an overview of those first few minutes (yes, MINUTES) of the universe’s life. It started with a Big Bang, when the Universe was incredibly dense and hot. It expanded and cooled, going through multiple stages where different kinds of matter could form. It underwent a phenomenally rapid expansion called inflation, which smoothed out much of the lumpiness in the matter. Normal matter formed atoms between 3 and 20 minutes after the bang, and the lumps left over from inflation formed the galaxies and larger structures we see today. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Table of Contents Mapping the History of the Universe Using Math and Observations 00:41 It Started With A Bang! 1:58 Rapid Expansion Smoothed Out Matter 4:55 Normal Matter Formed After 3-20 Minutes 5:12 -- 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 Proton Collision Event with Boosters and LHC https://www.youtube.com/watch?v=NhXMXiXOWAA [credit: ATLAS] Melting Snowball video courtesy of Phil Plait Big Bang to Hubble http://www.spacetelescope.org/videos/hst15_big_bang_to_hubble/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] Journey to the centre of the Sun http://www.spacetelescope.org/videos/astro_ac/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)] PIA16873: Best Map Ever of the Universe http://photojournal.jpl.nasa.gov/catalog/PIA16873 [credit: ESA and the Planck Collaboration] A high resolution foreground cleaned CMB map from WMAP http://space.mit.edu/home/tegmark/mapforegs.pdf [credit: Tegmark et al.] Planck comb rbcol scaled http://www.astro.cardiff.ac.uk/~spxcen/CMB_Sims/Planck_comb_rbcol_scaled.png [credit: Chris North, Cardiff University] WMAP's Portrait of the Early Universe http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10123 [credit: NASA]

As we approach the end of Crash Course Astronomy, it’s time now to acknowledge that our Universe’s days are numbered. Stars will die out after a few trillion years, protons will decay and matter will dissolve after a thousand trillion trillion trillion years, black holes will evaporate after 10^92 years, and then all will be dark. But there is still hope that a new Universe will be born from it. Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster -- Hawking Radiation Mechanism resources: https://en.wikipedia.org/wiki/Hawking_radiation http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/hawking.html http://casa.colorado.edu/~ajsh/hawk.html http://physics.stackexchange.com/questions/154647/how-does-the-hawking-radiation-mechanism-cause-a-black-hole-to-lose-its-mass -- Table of Contents The Universe’s Days Are Numbered 0:32 Stars Eventually Die Out 3:02 Protons Eventually Decay 5:04 Bye-Bye Black Holes After 10^92 Years 7:49 With Death Comes Life 12:04 -- 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 ACS SWEEPS Field http://hubblesite.org/gallery/album/star/star_field/pr2011016b/ [credit: NASA, ESA, W. Clarkson (Indiana University and UCLA), and K. Sahu (STScI)] Flare http://www.nasa.gov/sites/default/files/thumbnails/image/dg_cvn_flare_final_4k_0.jpg [credit: NASA's Goddard Space Flight Center/S. Wiessinger] Hubble Views Stellar Genesis in the Southern Pinwheel http://hubblesite.org/newscenter/archive/releases/2014/04/image/a/ [credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)] White Dwarf http://www.nasa.gov/multimedia/imagegallery/image_feature_468.html [credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester)] Neutron Star Illustrated https://commons.wikimedia.org/wiki/File:Neutron_star_illustrated.jpg [credit: NASA, Casey Reed - Penn State University] Black Holes: Monsters in Space http://www.nasa.gov/mission_pages/nustar/multimedia/pia16695.html [credit: NASA/JPL-Caltech] Binary Neutron Star Video https://nasaviz.gsfc.nasa.gov/vis/a030000/a030500/a030569/slide_04-B3_CWDB_inspiral.mp4 [credit: NASA] Giant Elliptical Galaxy NGC 1316 in Fornax Cluster https://www.eso.org/public/images/eso0024a/ [credit: ESO] Proton Aurora http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=20099 [credit: NASA/Goddard Space Flight Center Conceptual Image Lab] A Race Round a Black Hole http://www.nasa.gov/centers/goddard/universe/blackhole_race.html [credit: NASA/Dana Berry, SkyWorks Digital] The Big Bang http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10128 [credit: NASA] Hubble Ultra Deep Field 2014 http://hubblesite.org/newscenter/archive/releases/2014/27/image/a/ [credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)] Galaxy http://apod.nasa.gov/apod/ap150614.html [credit: Subaru Telescope (NAOJ), Hubble Space Telescope, Robert Gendler] One star, many stars (M13) http://www.deepskycolors.com/archive/2011/05/04/one-star-many-stars-M13.html [credit: Rogelio Bernal Andreo] Earth https://www.nasa.gov/content/goddard/earth-from-space-15-amazing-things-in-15-years [credit: NASA's Earth Observatory] Explosion video [credit: Shutterstock / Richard Finch]

Here it is, folks: the end. In our final episode of Crash Course Astronomy, Phil gives the course a send off with a look at some of his favorite topics and the big questions that Astronomy allows us to ask. Thank you for watching. -- Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster 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 Exoplanet, thick atmosphere - Artist’s Impression http://www.nasa.gov/images/content/681727main_kepler47_art_full.jpg [credit: NASA/JPL-Caltech/T. Pyle] Exoplanet, Earth-like - Artist’s Impression http://www.gemini.edu/images/pio/News/2014/pr2014_03/AAAS/quintana4HR.jpg [credit: NASA Ames/SETI Institute/JPL-CalTech] James Webb Space Telescope http://www.stsci.edu/~levay/presres/jwst/jwst05_new-config.jpg [credit: Northrop Grumman Space Technology] Hubble's High-Definition Panoramic View of the Andromeda Galaxy http://hubblesite.org/newscenter/archive/releases/2015/02/ [credit: NASA, ESA, J. Dalcanton, B.F. Williams, and L.C. Johnson (University of Washington), the PHAT team, and R. Gendler] Bennu's Journey http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=20220 [credit: NASA's Goddard Space Flight Center Conceptual Image Lab] Wedding Lanterns https://www.flickr.com/photos/jirka_matousek/12431704084 [credit: Jirka Matousek] Balloon https://en.wikipedia.org/wiki/Project_Echo#/media/File:Echo_II.jpg [credit: NASA] Naked-eye Venus photo taken by Phil Plait Cygnus Reentry https://www.flickr.com/photos/astro_alex/14760660030/in/set-72157645670772466/ [credit: ESA/NASA] Moon http://www.eso.org/public/archives/images/large/potw1023a.jpg [credit: G. Gillet/ESO] Progress M-10M reentry plasma trail https://commons.wikimedia.org/wiki/File:Progress_M-10M_reentry_plasma_trail.jpg [credit: NASA] Alien Worlds https://www.cfa.harvard.edu/sites/www.cfa.harvard.edu/files/images/pr/2011-30/1/hires.jpg [credit: David Aguilar / CfA] Beyond the Visible: The Story of the Very Large Array https://www.youtube.com/watch?v=RqX9vLj3_7w [credit: NRAO] Barred spiral bares all http://www.spacetelescope.org/images/potw1035a/ [credit: ESA/Hubble & NASA] Hi hello https://www.flickr.com/photos/bencanales/8745890764/sizes/l [credit: Ben Canales, http://www.thestartrail.com/]

Take a 360 degree virtual tour of our Solar System, with the help of Crash Course Astronomy host Phil Plait! Subscribe to Thought Café’s channel: http://bit.ly/1OhMPQC This video is part of Thought Café +, a collaborative animated series from the team behind the Crash Course animations! Check out more of their videos here: http://bit.ly/1KpGB0s For the most immersive #360Video experience use Cardboard (http://bit.ly/1HfYD5m) with the YouTube Android app. If you do not have Cardboard, you can use the YouTube apps for Android or iOS and move your mobile device to look around the solar system. On a desktop computer, use the latest versions of Chrome, Firefox, Internet Explorer, or Opera browsers to click and drag your mouse and follow along as we explore our Solar System.