DO NOT TIP. This is an unofficial YouTube mirror of PBS Space Time (https://youtu.be/3tCMd1ytvWg). If you want to tip PBS Space Time please visit https://www.patreon.com/pbsspacetime/. Convince PBS Space Time to join Odysee! ----------------------------- Want to ask some sort of crazy question about Space?: Tweet at us! @pbsspacetime Facebook: facebook.com/pbsspacetime Email us! pbsspacetime [at] gmail [dot] com Support us on Patreon! http://www.patreon.com/pbsspacetime Help translate our videos! http://www.youtube.com/timedtext_cs_panel?tab=2&c=UC7_gcs09iThXybpVgjHZ_7g HAS SPACE ALWAYS BEEN BLACK? As long as we've been around, YES. But the universe gets much more exciting, AND much BRIGHTER, as we start winding our clocks back to the early days of the universe. Near the beginning of the universe, when space was rapidly expanding, that dark night sky we know so well as actually…ORANGE! But why? Did the lights just go out, or did something more spectacular happen? Watch this episode of PBS Space Time and find out! Extra Credit: CMG Scissored Pair https://www.youtube.com/watch?v=S85Nticmi3Q ----------------------------------------­­­------------------------------- New SpaceTime episodes every Wednesday! Hosted by Gabe Perez-Giz Made by Kornhaber Brown (www.kornhaberbrown.com)

DO NOT TIP. This is an unofficial YouTube mirror of PBS Space Time (https://youtu.be/hmVOV7xvl58). If you want to tip PBS Space Time please visit https://www.patreon.com/pbsspacetime/. Convince PBS Space Time to join Odysee! ----------------------------- Viewers like you help make PBS (Thank you ?) . Support your local PBS Member Station here: https://to.pbs.org/DonateSPACE Neil deGrasse Tyson sits down with Matt to discuss Ancestor Simulations. And check out Matt and Neil discussing how sure we are about our map of the universe https://youtu.be/6Ng1wwW6AeE You can subcribe to Startalk right here https://www.youtube.com/subscription_center?add_user=startalkradio You can further support us on Patreon at https://www.patreon.com/pbsspacetime Get your own Space Time t­shirt at http://bit.ly/1QlzoBi Tweet at us! @pbsspacetime Facebook: facebook.com/pbsspacetime Email us! pbsspacetime [at] gmail [dot] com Comment on Reddit: http://www.reddit.com/r/pbsspacetime Help translate our videos! https://www.youtube.com/timedtext_cs_panel?tab=2&c=UC7_gcs09iThXybpVgjHZ_7g Previous Episode: The Boltzmann Brain https://www.youtube.com/watch?v=nhy4Z_32kQo The Oh My God Particle https://www.youtube.com/watch?v=osvOr5wbkUw The idea that our reality is a simulation is not as far-fetched as you may think. Many philosophers, scientists and tech-billionaires are seriously considering not just the possibility but the high probability that our civilization may be a program being run by another, more advanced alien civilization. Written and Hosted by Matt O’Dowd Produced by Rusty Ward Graphics by Kurt Ross Made by Kornhaber Brown (www.kornhaberbrown.com) Comments answer by Matt: 0xFFF1 https://www.youtube.com/watch?v=osvOr5wbkUw&lc=z12lxde4hoyvhn4mi23sjnwjrwnljxe3m KohuGaly https://www.youtube.com/watch?v=nhy4Z_32kQo&lc=z13miz0bsnbzfrkpi04cflm5ykuluxbzeug0k Henry School https://www.youtube.com/watch?v=nhy4Z_32kQo&lc=z12av3hgurvuin2lo225gphqhwysj5lft exurb1a https://www.youtube.com/watch?v=nhy4Z_32kQo&lc=z135gzlznojtjzitt23rxl1zmzi0gx3ha04 Special thanks to our Patreon Big Bang, Quasar and Hypernova Supporters: Big Bang Shane Robinson David Nicklas Samuel Dean Jacintho Quasar Tambe Barsbay Coolascats Avan & Kyan Griggs Max Levine Hypernova Science Via Markets Chuck Zegar Craig Peterson Jordan Young Ratfeast John Hofmann Joseph Salomone Thanks to our Patreon Gamma Ray Burst Supporters: Justin Lloyd Conor Dillon Jared Moore Michal-Peanut Karmi Bernardo Higuera Erik Stein Daniel Lyons Jade Bilkey Kevin Warne JJ Bagnell J Rejc Dylan Merida Anthony Caridi Avi Goldfinger John Pettit Shannan Catalano Florian Stinglmayr Yubo Du Benoit Pagé-Guitard Ronny Polonia Nathan Leniz Jessica Fraley Kirk Mathews Carl P. Corliss Brandon labonte David Crane Greg Weiss

DO NOT TIP. This is an unofficial YouTube mirror of PBS Space Time (https://youtu.be/P4rW_pPbD-U). If you want to tip PBS Space Time please visit https://www.patreon.com/pbsspacetime/. Convince PBS Space Time to join Odysee! ----------------------------- What can you trust in Spacetime? Tweet at us! @pbsspacetime Facebook: facebook.com/pbsspacetime Email us! pbsspacetime [at] gmail [dot] com Comment on Reddit: http://www.reddit.com/r/pbsspacetime Support us on Patreon! http://www.patreon.com/pbsspacetime Help translate our videos! http://www.youtube.com/timedtext_cs_panel?tab=2&c=UC7_gcs09iThXybpVgjHZ_7g Last time we talked about what curvature means, looked at geodesics, great circles on spheres, and tried to understand the notion of "straightness". This week on Spacetime, we take a detour into how geometry works in spacetime. Get excited, because this episode is even more mind-bending than the last! Past Episodes On SpaceTime: "Are Space And Time An Illusion?": https://www.youtube.com/watch?v=YycAzdtUIko "Is Gravity An Illusion?" https://www.youtube.com/watch?v=NblR01hHK6U "Can A Circle Be A Straight Line?" https://www.youtube.com/watch?v=D3GVVkPb3OI Let us know what topics you want to learn more about: http://bit.ly/spacetimepoll Extra Credit: Overview of Special Relativity and spacetime: www.youtube.com/watch?v=ScdLqAA_64E www.youtube.com/watch?v=aeCsS6PjhK8 www.youtube.com/watch?v=NAXHHBUY9_E http://www.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/spacetime/ http://en.wikibooks.org/wiki/Special_Relativity/Spacetime Brian Greene's introduction to special relativity (thanks to viewer Mark G for pointing out these courses!) http://www.worldscienceu.com/courses/university/space-time-and-einstein (no math) http://www.worldscienceu.com/courses/university/special-relativity (more math) Disagreement about event sequence (relativity of simultaneity): http://en.wikibooks.org/wiki/Special_Relativity/Simultaneity,_time_dilation_and_length_contraction#More_about_the_relativity_of_simultaneity ----------------------------------------­­­­­­­­­­­­­­­--------------------------­-­-­-­-­- Music: u dont know im fadin Secret Society - Logical Disorder (http://logicaldisorder.bandcamp.com/) Movement 3 - Janne Hanhisuanto (https://soundcloud.com/jannehanhisuanto) Philly D Jr - Patternbased (https://soundcloud.com/patternbased) Earth Breath - Human Terminal (http://freemusicarchive.org/music/Hum...) Deep Blue - Janne Hanhisuanto (https://soundcloud.com/jannehanhisuanto) Saw Slicing - Patternbased (https://soundcloud.com/patternbased) Heisse Luft - Thompson and Kuhl (https://soundcloud.com/phlow/05-x-com) miracle - slow (http://www.restingbell.net/releases/r) Tropico de Tauro - Sr. Aye https://soundcloud.com/sr-aye) New SpaceTime episodes every Wednesday! Hosted by Gabe Perez-Giz Made by Kornhaber Brown (www.kornhaberbrown.com)

DO NOT TIP. This is an unofficial YouTube mirror of PBS Space Time (https://youtu.be/5t0jaE--l0Y). If you want to tip PBS Space Time please visit https://www.patreon.com/pbsspacetime/. Convince PBS Space Time to join Odysee! ----------------------------- You can learn more about CuriosityStream at https://curiositystream.com/spacetime PBS Member Stations rely on viewers like you. To support your local station, go to: http://to.pbs.org/DonateSPACE We’ve been failing to detect dark matter for decades. Finally, the latest failure to detect dark matter may have actually proved its existence. One of these is true: either most of the matter in the universe is invisible and formed of something not explained by modern particle physics OR our understanding of gravity is completely broken. The debate over which is true has raged for decades, but may finally have been resolved in an unlikely way: the proof that dark matter exists, and really is an exotic, unknown substance, may have come from the discovery of two galaxies that appear to have no dark matter at all. Today on Space Time Journal Club we’ll look at the papers that reveal this discovery: Check out the new Space Time Merch Store! https://pbsspacetime.com/ Support Space Time on Patreon https://www.patreon.com/pbsspacetime Need a Refresher to Fully Understand the Holographic Principle? https://www.youtube.com/playlist?list=PLsPUh22kYmNCHVpiXDJyAcRJ8gluQtOJR #darkmatter #astrophysics #spacetime Hosted by Matt O'Dowd Written by Matt O'Dowd Graphics by Kurtis Ross Directed by Andrew Kornhaber Produced By: Kornhaber Brown The effect of dark matter was first noticed in 1933, when the legendary Swiss astrophysicist Fritz Zwicky noticed that the galaxies in the Coma cluster were moving too quickly to remain gravitationally bound within that cluster. He guessed the presence of “dunkle m aterie” – a dark matter invisible to his telescope but whose gravitational effect held the cluster together. As with many of Zwicky’s predictions – like the existence of neutron stars and gravitational lensing - this wasn’t taken seriously until decades later. The hunt for dark matter began in earnest after the early 70s when Vera Ruben, discovered that the rotation rates of spiral galaxies were too fast given the mass of their visible stars alone. They should throw themselves to pieces spinning that quickly – that is, unless, a gravitational force of unseen origin was holding them together. Special thanks to our Patreon Big Bang, Quasar and Hypernova Supporters: Big Bang: Anton Lifshits David Nicklas Fabrice Eap Juan Benet Quasar: Mark Rosenthal Tambe Barsbay Vinnie Falco Hypernova: Antoine Bruguier chuck zegar Danton Spivey Donal Botkin Edmund Fokschaner John Hofmann Jordan Young Joseph Salomone kkm Mark Heising Matthew Matthew O'Connor Thanks to our Patreon Gamma Ray Burst Supporters: Adrien Moyneux Alexander Lazerev Alexey Eromenko Andrewas Nautsch Antonio Ruiz Bradley Jenkins Brandon Labonte Buruk Aregawi Carlo Mogavero Daniel Lyons David Behtala Dustan Jones Geoffrey Short James Flowers James Quintero John Funai John Pollock Jonah Joseph Dillman Joseph Emison Josh Thomas Kevin Warne Kyle Hofer Malte Ubl Mark Vasile Nathan Hitchings Nicholas Rose Nick Virtue Ratfeast Ryan Jones Scott Gossett Sigurd Ruud Frivik Tim Crookham Tim Stephani Tommy Mogensen Yurii Konovaliuk سلطان الخليفي