DO NOT TIP. This is an unofficial YouTube mirror of PBS Space Time (https://youtu.be/V5kgruUjVBs). 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 In simple terms a gauge theory is one that has mathematical parameters, or “degrees of freedom” that can be changed without affecting the predictions of the theory. You can further support us on Patreon at https://www.patreon.com/pbsspacetime Get your own Space Time t­-shirt 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_... Previous Episode: Will A New Neutrino Change The Standard Model? https://www.youtube.com/watch?v=0mXW1zPlxEE&t As far as we can tell, mathematics is the language in which the universe is written. Our laws of physics are equations of motion, along with some associated constants. Previously we’ve talked a bit about the symmetries of these equations, and how they lead us to conserved quantities. But this is just the tip of the theoretical iceberg - sometimes investigating the symmetries of these equations predicts entirely new physics. The most remarkable example of this is the standard model of particle physics. You know, the most accurate physical theory in all of human history. Hosted by Matt O'Dowd Written by Graeme Gossel and Matt O'Dowd Graphics by Grayson Blackmon Assistant Editing and Sound Design by Mike Petrow Made by Kornhaber Brown (www.kornhaberbrown.com) Special thanks to our Patreon Big Bang, Quasar and Hypernova Supporters: Big Bang CoolAsCats David Nicklas Anton Lifshits Joey Redner Fabrice Eap Quasar Tambe Barsbay Mayank M. Mehrota Mars Yentur Mark Rosenthal Dean Fuqua Roman Pinchuk ColeslawPurdie Vinnie Falco Hypernova Donal Botkin Edmund Fokschaner Matthew O’Connor Eugene Lawson Barry Hatfield Martha Hunt Joseph Salomone Chuck Zegar Craig Peterson Jordan Young Ratfeast John Hofmann Thanks to our Patreon Gamma Ray Burst Supporters: James Hughes Fabian Olesen Kris Fernet Jane Meyers James Flowers Greg Allen Denys Ivanov Nick Virtue Alexey Eromenko Nicholas Rose Scott Gossett Mark Vasile Patrick Murray سلطان الخليفي Alex Seto Michal-Peanut Karmi Erik Stein Kevin Warne JJ Bagnell Avi Goldfinger John Pettit Florian Stinglmayr Benoit Pagé-Guitard Nathan Leniz Brandon Labonte David Crane Greg Weiss Shannan Catalano Brandon Cook Malte Ubl

DO NOT TIP. This is an unofficial YouTube mirror of PBS Space Time (https://youtu.be/-4PayaEgEZc). If you want to tip PBS Space Time please visit https://www.patreon.com/pbsspacetime/. Convince PBS Space Time to join Odysee! ----------------------------- Part 2 in our Dark Energy series. Part 1: https://www.youtube.com/watch?v=xZTb6sfHEX8 Check out our sister channel Crash Course Physics to learn more about the basic foudations of Physics: https://www.youtube.com/watch?v=ZM8ECpBuQYE&list=PL8dPuuaLjXtN0ge7yDk_UA0ldZJdhwkoV Get your own Space Time t-shirt 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 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 Now that we know the universe will continue to expand forever, we can begin to complete the first Friedmann equation, and determine the shape and geometry of our universe. At first glance, it would seem that the equation doesn’t quite add up, and that our universe is a hyperbolic plane. But when we add in the cosmological constant, the equation balances out, and we return to a flat universe. _____________________ COMMENTS: Deiter Meena https://www.youtube.com/watch?v=xZTb6sfHEX8&lc=z13uzj2y2uf2xl3ck23zwfuxkqyzidsfh Jack W https://www.youtube.com/watch?v=xZTb6sfHEX8&lc=z13rih2gupnudr3x004cjbw4pyryezmi0ig Mychelly Goulart https://www.youtube.com/watch?v=xZTb6sfHEX8&lc=z13mzpkq3qauip1xw04cjvoxxsj1fhv5uac Tomek Wooff https://www.youtube.com/watch?v=xZTb6sfHEX8&lc=z12hxbtrbvezin5ra04cd3cyrou3fxk55o00k Mr B https://www.youtube.com/watch?v=xZTb6sfHEX8&lc=z13qfhkoclzqf11dx235d3zj0zucyjsxj04 ______________________ Written and hosted by Matt O’Dowd Made by Kornhaber Brown (www.kornhaberbrown.com)

DO NOT TIP. This is an unofficial YouTube mirror of PBS Space Time (https://youtu.be/BAoEnV3Zt_Q). If you want to tip PBS Space Time please visit https://www.patreon.com/pbsspacetime/. Convince PBS Space Time to join Odysee! ----------------------------- The Drake Equation tells us the likelihood that there are other advanced technological civilizations waiting for us among the stars. In this episode of Space Time we challenge you to use the Drake Equation to help us determine how near or far these alien races may be. Links to reference material below. 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 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 Everything we’ve learned about our universe tells us that it is very unlikely we are alone. Frank Drake and his Drake Equation compute exactly how unlikely this is. The answer may surprise you. Written and hosted by Matt O’Dowd Produced by Rusty Ward Made by Kornhaber Brown (www.kornhaberbrown.com) A New Empirical Constraint on the Prevalence of Technological Species in the Universe Adam Frank & W.T. Sullivan III https://arxiv.org/abs/1510.08837 The Drake Equation http://www.seti.org/drakeequation G-type stars within 100 light years http://www.solstation.com/stars3/100-gs.htm Prevalence of Earth-size planets orbiting Sun-like stars Erik A. Petigura, Andrew W. Howard, Geoffrey W. Marcy https://arxiv.org/abs/1311.6806 The Kepler Sample http://kepler.nasa.gov/science/about/targetFieldOfView/ Planet Hunters X. KIC 8462852 - Where's the Flux? Tabby. S. Boyajian, et al. https://arxiv.org/abs/1509.03622

DO NOT TIP. This is an unofficial YouTube mirror of PBS Space Time (https://youtu.be/QTZZUjnrbF8). If you want to tip PBS Space Time please visit https://www.patreon.com/pbsspacetime/. Convince PBS Space Time to join Odysee! ----------------------------- PBS Member Stations rely on viewers like you. To support your local station, go to: http://to.pbs.org/DonateSPACE ↓ More info below ↓ Check out Antarctic Extremes on PBS Terra: https://www.youtube.com/watch?v=EvRAuy1ZmTc Sign Up on Patreon to get access to the Space Time Discord! https://www.patreon.com/pbsspacetime Sign up for the mailing list to get episode notifications and hear special announcements! https://tinyurl.com/yx9cusk5 Check out the Space Time Merch Store https://pbsspacetime.com/ To quote eminent scientist Tyler Durden: "On a long enough timeline, the survival rate for everyone drops to zero." Actually… not necessarily true. If the quantum multiverse is real there may be a version of you that lives forever. Hosted by Matt O'Dowd Written by Matt O'Dowd Graphics by Leonardo Scholzer, Yago Ballarini, & Pedro Osinski Directed by: Andrew Kornhaber Executive Producers: Eric Brown & Andrew Kornhaber End Credits Music by J.R.S. Schattenberg: https://www.youtube.com/channel/UCRl6-nb4iOnsij-vnpAjp0Q If we can’t ever peer into these other realities that are used to explain quantum mechanics, how do we know they exist? In order to understand what happens to those different branches, and to understand why we find ourselves in one of them, we need to embrace one of the interpretations of quantum mechanics. For example the Copenhagen interpretation, which says that the wavefunction branches that we don’t observe somehow vanish at the moment of measurement. Or the Many Worlds interpretation, which states that those other branches are just as valid as ours - implying that reality may split and multiply in all possible ways. In that case we only see one branch because we live in that branch, and the others are rendered inaccessible by decoherence. But today I’m going to offer a test. Admittedly NOT a very useful one - but one that’s fun to think about. We’ll call this test quantum immortality. It’s based on the famous Schrodinger’s cat thought experiment. Special Thanks to Our Patreon Sponsors Big Bang Supporters Alexander Tamas David Barnholdt David Nicklas Fabrice Eap Juan Benet Morgan Hough Quasar Supporters Christina Oegren Mark Heising Vinnie Falco Hypernova Supporter Chuck Zegar Danton Spivey Donal Botkin Douglas Cantrell Edmund Fokschaner Hank S John Hofmann John Pollock John R. Slavik Jordan Young Joseph Salomone Julian Tyacke Justin Ash Mathew Matthew O'Connor Syed Ansar Timothy McCulloch Gamma Ray Burst Supporters A G Adrian Hatch Adrien Molyneux AlecZero Andreas Nautsch Angela Prigge Arefa Ahmad Bradley Jenkins Brandon labonte Brian Blanchard Craig Stonaha Dan Warren Daniel Lyons David Bethala DFaulk Eric Kiebler Frederic Simon Geoffrey Short Graydon Goss Greg Smith John Funai John Robinson Jonathan Nesfeder Josh Thomas Kevin Lee Kevin Warne Kyle Hofer Malte Ubl Michael Conroy Nick Virtue Nick Wright Nickolas Andrew Freeman Patrick Sutton Paul Rose Protius Protius Randall Sylvia Robert Ilardi Scott Gossett Sean Warniaha Shane Calimlim Sipke Schoorstra Steve Bradshaw Tatiana Vorovchenko Tim Stephani Tonyface Tybie Fitzhugh Yurii Konovaliuk