Summary
The ongoing quest to reconcile general relativity and quantum mechanics remains one of the most significant challenges in modern physics. Despite their success in explaining a vast array of phenomena, these two foundational theories fundamentally contradict each other. General relativity, formulated by Einstein, describes gravity as the warping of space-time by mass and energy, while quantum mechanics operates on the probabilistic behavior of particles at the subatomic level. The inability to unify these theories has led to a search for a deeper understanding of the universe, often referred to as the theory of quantum gravity.
Key conflicts arise when attempting to apply quantum principles to gravity. For instance, the Heisenberg uncertainty principle suggests that measuring a particle's position with extreme precision requires immense energy, potentially creating black holes at the Planck scale. This paradox highlights the limitations of our current understanding, as the fabric of space-time itself must be quantized to accurately describe gravity. However, attempts to do so have led to non-renormalizable equations, indicating that our existing theories may be insufficient.
Several approaches are being explored to bridge this gap, including loop quantum gravity and string theory. Loop quantum gravity seeks to quantize general relativity without the infinities that plague current models, while string theory posits that space-time and gravity are emergent phenomena from a more fundamental quantum framework. As physicists continue to grapple with these complex issues, the pursuit of a unified theory remains a central focus, promising to reshape our understanding of the universe.
Show Notes
Viewers like you help make PBS (Thank you 😃) . Support your local PBS Member Station here: https://to.pbs.org/DonateSPACEUploaded 20-09-18Between them, general relativity and quantum mechanics seem to describe all of observable reality. You can further support us on Patreon at https://www.patreon.com/pbsspacetimeGet your own Space Time t-shirt at http://bit.ly/1QlzoBiTweet at us! @pbsspacetimeFacebook: facebook.com/pbsspacetimeEmail us! pbsspacetime [at] gmail [dot] comComment on Reddit: http://www.reddit.com/r/pbsspacetimeHelp translate our videos!https://www.youtube.com/timedtext_cs_...Previous Episode:How Much Information is in the Universe?https://www.youtube.com/watch?v=XxVlGAFX7vAHosted by Matt O'DowdWritten by Matt O'DowdGraphics by Luke MaroldiAssistant Editing and Sound Design by Mike PetrowMade by Kornhaber Brown (www.kornhaberbrown.com)The first few decades of the 20th century was a time of miracles for physics. First, Einstein’s relativity utterly changed the way we think about space, time, motion and gravity. Then the quantum revolution of the 20s and 30s overturned all of our intuitions about the subatomic world. Together, general relativity and quantum mechanics have allowed us to explain nearly every fundamental phenomenon observed, and have predicted many unexpected phenomena that have since been verified. And yet the two theories contradict each other in fundamental ways. In the century since that golden era of physics, we’ve been trying to reconcile the two … without success. But today on space-time I’m going to begin our discussion of the great quest for this union – the quest for a theory of quantum gravity, and for a theory of everything.Special thanks to our Patreon Big Bang, Quasar and Hypernova Supporters: Big BangAnton LifshitsCoolAsCatsDavid NicklasFabrice EapQuasarDean FuquaMark RosenthalMayank M. MehrotaRoman PinchukTambe BarsbayVinnie FalcoHypernovaBrent MullinsChuck ZegarDonal BotkinEdmund FokschanerJohn HofmannJordan YoungJoseph SalomoneMatthew O’ConnorRatfeastThanks to our Patreon Gamma Ray Burst Supporters: Alexander RodriguezAlexey EromenkoBenoit Pagé-GuitardBrandon CookBrandon LabonteDaniel LyonsDavid CraneDeborah WhittakerFabian OlesenGreg AllenGreg WeissJames FlowersJames HughesJJ BagnellJon FolksKevin WarneMalte UblMark VasileNicholas RoseNick VirtueScott GossettShannan Catalanoسلطان الخليفي Learn more about your ad choices. Visit megaphone.fm/adchoices Learn more about your ad choices. Visit megaphone.fm/adchoices
More from PBS Space Time
PBS Member Stations rely on viewers like you. To support your local station, go to: http://to.pbs.org/DonateSPACE↓ More info below ↓Uploaded 03-03-20Check out Antarctic Extremes on PBS Terra: https://www.youtube.com/watch?v=EvRAuy1ZmTcSign Up on Patreon to get access to the Space Time Discord! https://www.patreon.com/pbsspacetimeSign up for the mailing list to get episode notifications and hear special announcements!https://tinyurl.com/yx9cusk5Check out the Space Time Merch Storehttps://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'DowdWritten by Matt O'DowdGraphics by Leonardo Scholzer, Yago Ballarini, and Pedro OsinskiDirected by: Andrew KornhaberExecutive Producers: Eric Brown and Andrew KornhaberEnd Credits Music by J.R.S. Schattenberg: https://www.youtube.com/channel/UCRl6-nb4iOnsij-vnpAjp0QIf 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 SponsorsBig Bang SupportersAlexander TamasDavid BarnholdtDavid NicklasFabrice EapJuan BenetMorgan HoughQuasar SupportersChristina OegrenMark HeisingVinnie FalcoHypernova SupporterChuck ZegarDanton SpiveyDonal BotkinDouglas CantrellEdmund FokschanerHank SJohn HofmannJohn PollockJohn R. SlavikJordan YoungJoseph SalomoneJulian TyackeJustin AshMathewMatthew O'ConnorSyed AnsarTimothy McCullochGamma Ray Burst SupportersA GAdrian HatchAdrien MolyneuxAlecZeroAndreas NautschAngela PriggeArefa AhmadBradley JenkinsBrandon labonteBrian BlanchardCraig StonahaDan WarrenDaniel LyonsDavid BethalaDFaulkEric KieblerFrederic SimonGeoffrey ShortGraydon GossGreg SmithJohn FunaiJohn RobinsonJonathan NesfederJosh ThomasKevin LeeKevin WarneKyle HoferMalte UblMichael ConroyNick VirtueNick WrightNickolas Andrew FreemanPatrick SuttonPaul RoseProtius ProtiusRandall SylviaRobert IlardiScott GossettSean WarniahaShane CalimlimSipke SchoorstraSteve BradshawTatiana VorovchenkoTim StephaniTonyfaceTybie FitzhughYurii Konovaliuk Learn more about your ad choices. Visit megaphone.fm/adchoices Learn more about your ad choices. Visit megaphone.fm/adchoices
Viewers like you help make PBS (Thank you 😃) . Support your local PBS Member Station here: https://to.pbs.org/DonateSPACEUploaded 17-05-17How will humanity evolve after landing and living on Mars? Try 23andMe at http://23andme.com/spacetime And check out the new PBS Digital Studios channel Above the Noise https://www.youtube.com/channel/UC4K10PNjqgGLKA3lo5V8KdQYou can further support us on Patreon at https://www.patreon.com/pbsspacetimeGet your own Space Time tshirt at http://bit.ly/1QlzoBiTweet at us! @pbsspacetimeFacebook: facebook.com/pbsspacetimeEmail us! pbsspacetime [at] gmail [dot] comComment on Reddit: http://www.reddit.com/r/pbsspacetimeHelp translate our videos! https://www.youtube.com/timedtext_cs_panel?tab=2&c=UC7_gcs09iThXybpVgjHZ_7gPrevious Episode:The Great American Eclipsehttps://www.youtube.com/watch?v=nsWhE22i4FMWhat will become of humanity after spend a few hundred years on Mars? What will happen after a few thousand? Evolution has, and still is, shaping humanity in rather drastic ways. How long will humans stop being human and become Martian?Written and Hosted by Matt O’Dowd Produced by Rusty WardGraphics by Kurt RossMade by Kornhaber Brown (www.kornhaberbrown.com)Comments answer by Matt:Martin Kettlinghttps://www.youtube.com/watch?v=nsWhE22i4FM&lc=z12qibnb5qedg3m5z04cinshttjbydrrj4svenkata raju Pothurihttps://www.youtube.com/watch?v=nsWhE22i4FM&lc=z124exgrmxm5gvzkr23rxnsjssr3f3ymlIfslayancthttps://www.youtube.com/watch?v=nsWhE22i4FM&lc=z12gxzhyzpe2g55ex23hilqjqqebgpc1lZach Grallhttps://www.youtube.com/watch?v=nsWhE22i4FM&lc=z12ztlia1tu4xvqa504cflzrwp3xt3l4rws0kMatt Dillhttps://www.youtube.com/watch?v=nsWhE22i4FM&lc=z13acjswqpq2wtlq404civoihxzuj5gga0sSpecial thanks to our Patreon Big Bang, Quasar and Hypernova Supporters: Big BangShane RobinsonDavid NicklasSamuel Dean JacinthoEugene LawsonQuasarTambe BarsbayCoolascatsAvan and Kyan GriggsMax LevineHypernovaScience Via MarketsChuck ZegarJordan YoungRatfeastJohn HofmannJoseph Salomone Thanks to our Patreon Gamma Ray Burst Supporters: Justin LloydConor DillonJared MooreMichal-Peanut KarmiBernardo HigueraErik SteinDaniel LyonsJade BilkeyKevin WarneJJ BagnellJ RejcDylan MeridaAnthony CaridiAvi GoldfingerJohn PettitShannan CatalanoFlorian StinglmayrYubo DuBenoit Pagé-GuitardRonny PoloniaNathan LenizJessica FraleyKirk MathewsCarl P. CorlissBrandon labonteDavid CraneGreg Weiss Learn more about your ad choices. Visit megaphone.fm/adchoices Learn more about your ad choices. Visit megaphone.fm/adchoices
Check Out Subcultured's Anime Episode on PBS Voices: https://youtu.be/oSCj8H4TGToUploaded 16-03-22Take the Space Time Fan Survey Here: https://forms.gle/wS4bj9o3rvyhfKzUAPBS Member Stations rely on viewers like you. To support your local station, go to:http://to.pbs.org/DonateSPACEIf you've studied any physics you know that like charges repel and opposite charges attract. But why? It's as though this thing - electric charge - is as fundamental a property of an object as its mass. It just sort of ... is. Well it turns out if you dig deep enough, the fundamental-ness of charge unravels, and in many things, including mass itself, are unraveled with it.Sign Up on Patreon to get access to the Space Time Discord!https://www.patreon.com/pbsspacetimeCheck out the Space Time Merch Storehttps://www.pbsspacetime.com/shopSign up for the mailing list to get episode notifications and hear special announcements!https://mailchi.mp/1a6eb8f2717d/spacetimeHosted by Matt O'DowdWritten by Fernando Franco Félix and Matt O'Dowd Post Production by Leonardo Scholzer, Yago Ballarini, Pedro Osinski, Adriano Leal and Stephanie FariaGFX Visualizations: Ajay ManuelDirected by Andrew KornhaberAssistant Producer: Setare GholipourExecutive Producers: Eric Brown and Andrew KornhaberExecutives in Charge (PBS): Adam Dylewski, Maribel Lopez Director of Programming (PBS): Gabrielle Ewing Spacetime is produced by Kornhaber Brown for PBS Digital Studios.This program is produced by Kornhaber Brown, which is solely responsible for its content.© 2021 PBS. All rights reserved.End Credits Music by J.R.S. Schattenberg: https://www.youtube.com/user/MultiDroidekaSpecial Thanks to Our Patreon SupportersBig Bang Sponsorsrpeterson2205Mark EvansDavid TaicletBen DimockDaniel AlexiucNenado763Peter BarrettDavid NeumannCharlieLeo KoguanSandy WuAhmad JodehAlexander TamasMorgan HoughAmyJuan BenetVinnie FalcoFabrice EapMark RosenthalDavid NicklasHenry Van StynQuasarAlex KinseyAlex KernEthan CohenStephen WilcoxChristina OegrenMark HeisingHank SHypernovawilliam bryanSergio BonfigliodrollereJoe MoreiraMarc ArmstrongScott GorlickPaul Stehr-GreenAdam WaltersRussell PopeBen DeloScott GrayАнтон КочковJohn R. SlavikMathewDonal BotkinJohn PollockEdmund FokschanerJoseph Salomonechuck zegarJordan YoungDaniel MuzquizGamma Ray Burst SupportersMatt QWhizBangeryTony AffinitoAvi YashchinMHL SHSKory KirkTerje VoldAnatoliy NagornyycomboyBrett BakerJeremy SollerJonathan ConerlyAndre StechertRoss BohnerPaul WoodKent Durhamjim bartoshNubbleChris NavridesScott R CalkinsThe Mad MechanicEllis HallJohn H. Austin, Jr.Diana SBen CampbellFaraz KhanAlmog CohenAlex EdwardsÁdám KettingerMD3Endre PechDaniel JenningsCameron SampsonPratik MukherjeeGeoffrey ClarionNateDarren DuncanRuss CreechJeremy ReedEric WebsterDavid JohnstonWeb BrowserMichael BartonChristopher BarronJames RamseyJustin JermynMr TAndrew MannIsaac SuttellDevon RosenthalOliver FlanaganBleys GoodsonRobert WalterBruce BSimon OliphantMirik GogriMark DelagasseMark Daniel CohenBrandon LattinNickolas Andrew FreemanShane CalimlimTybie FitzhughRobert IlardiEric KieblerCraig StonahaMartin SkansThe Art of SinGraydon GossFrederic SimonTonyfaceJohn RobinsonA GDavid NealKevin LeejustahatJohn FunaiCass CostelloTristanBradley JenkinsKyle HoferDaniel StříbrnýLuaanAlecZeroCodyKing ZeckendorffNick VirtueScott GossettDan WarrenPatrick SuttonDaniel LyonsDFaulkKevin Warne Learn more about your ad choices. Visit megaphone.fm/adchoices Learn more about your ad choices. Visit megaphone.fm/adchoices
Viewers like you help make PBS (Thank you 😃) . Support your local PBS Member Station here: https://to.pbs.org/DonateSPACEUploaded 13-06-18You can get a free trial of The Great Courses Plus at http://ow.ly/c7tI30hIva3We’ve established by now that black holes are weird. The result of absolute gravitational collapse of a massive body: a point of hypothetical infinite density surrounded by an event horizon. At that horizon time is frozen and the fabric of space itself cascades inwards at the speed of light. Nothing can travel faster than light, and so nothing can escape from below the event horizon- not matter, not light, not even information. You can further support us on Patreon at https://www.patreon.com/pbsspacetimeGet your own Space Time t-shirt at http://bit.ly/1QlzoBiTweet at us! @pbsspacetimeFacebook: facebook.com/pbsspacetimeEmail us! pbsspacetime [at] gmail [dot] comComment on Reddit: http://www.reddit.com/r/pbsspacetimeHelp translate our videos!https://www.youtube.com/timedtext_cs_panel?tab=2&c=UC7_gcs09iThXybpVgjHZ_7gPrevious Episode:Why Quantum Information is Never Destroyed https://youtu.be/HF-9Dy6iB_4These ideas are pretty mind-blowing, but as crazy as black holes are, they’re also kind of … simple. Don’t get me wrong; the math is complicated. But the objects themselves are simple. In fact every black hole in the universe, no matter how it formed or what happened to it afterwards, can be perfectly described with only three properties. Those properties are mass, angular momentum, and electric charge. Or at least this is the proposition behind the famous no-hair conjecture, or no-hair theorem. Written and hosted by Matt O'DowdGraphics by Grayson BlackmonAssistant Editing and Sound Design by Mike Petrow and Linda HuangMade by Kornhaber Brown (www.kornhaberbrown.com)Special thanks to our Patreon Big Bang, Quasar and Hypernova Supporters: Big BangCoolAsCatsDavid NicklasAnton LifshitsJoey RednerFabrice EapQuasarTambe BarsbayMayank M. MehrotaMars YenturMark RosenthalDean FuquaRoman PinchukColeslawPurdieHypernovaEdmund FokschanerMatthew O’ConnorEugene LawsonBarry HatfieldMartha HuntJoseph SalomoneChuck ZegarCraig PetersonJordan YoungRatfeastJohn HofmannThanks to our Patreon Gamma Ray Burst Supporters: James HughesFabian OlesenKris FernetJane MeyersJames FlowersGreg AllenDenys IvanovNick VirtueAlexey EromenkoNicholas RoseScott GossettMark VasilePatrick MurraySultan AlkhulaifiAlex SetoMichal-Peanut KarmiErik SteinKevin WarneJJ BagnellAvi GoldfingerJohn PettitFlorian StinglmayrBenoit Pagé-GuitardNathan LenizBrandon LabonteDavid CraneGreg WeissShannan CatalanoBrandon CookThe Great Courses Plus is currently available to watch through a web browser to almost anyone in the world and optimized for the US, UK, and Australian markets. The Great Courses Plus is currently working to both optimize the product globally and accept credit card payments globally. Learn more about your ad choices. Visit megaphone.fm/adchoices Learn more about your ad choices. Visit megaphone.fm/adchoices
PBS Member Stations rely on viewers like you. To support your local station, go to:http://to.pbs.org/DonateSPACE