Brian Greene and Cumrun Vafa: Fundamental Lessons From String Theory

Harvard professor and 2017 Breakthrough prize winner in Fundamental Physics, Cumrun Vafa joins Brian Greene for a discussion on the past and future of string theory and how puzzles ignited Cumrun’s interest in physics.
This program is part of the Big Ideas series, supported by the John Templeton Foundation.
Live Sessions are conversations hosted by Brian Greene with world-renowned scientists, including World Science U faculty exploring matter, mind, and the cosmos.
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[@alexneil394]

Holy… one of the most brilliant things I’ve ever heard. “Math can’t measure the universes magic , it just adds to the spell” It’s hilarious because I have ZERO formal education in any of these topics lol I try hardest to understand them and gain immense knowledge any ways.

[@johnkijkt2713]

Brian greene is a science communicating hero. He can't get enough credit for that. I am a fan from the netherlands. Regards!

[@AbiJaay]

This started playing while I was asleep and I dreamt along and I woke up in an absolute daze. My mind was blown while listening to this and my dream visualising it. I literally woke up smarter.

[@triqpham]

I just love the fact that Brian is so respectful and compassionate to all questions and people. Some questions can be a little ridiculous but he never condescends or laughs at them. He simply answers them respectfully. Thank you Brian. You are the best.

[@TillMeyenburg]

Thank you Mr. Greene for everything

[@prayogdash3564]

Thank you professor Greene and professor Vafa for your deep insight in string theory. And also for congratulating me and i am looking forward to read your book. "Puzzles to unravel the universe"!!!

[@SENATORPAIN1]

@@Bibibosh cumrun

[@SENATORPAIN1]

@@Bibibosh I needed time to think

[@jmisic]

Even though I am no physicistI I have a huge admiration for Brian Greene. I highly respect such pioneers. People who sacrifice their time and energy answering questions on behalf of humanity. I have no mathematical understanding of what is being said, but Greene must be a brilliant teacher. He makers complicated things sound real simple.Thank you and God bless Brian Greene

[@johnjobs3027]

Thanks Dr Greene. A huge fan of your books and programs.. Reading your books propelled me to become an amature physisist.

[@Josesdad]

Ration, reason, and a gift for comminication. I listen in or replay an episode nearly every day and contribute what I can. I wish my physics profs had been able to capture my interest and imagination as you have. Better late than never! Thanks from an old man.

[@oma2635]

if IAM old Men IAM pizza

[@oma2635]

🍕 pizza this is Old man

[@MrVikingsandra]

I just finished this, what a trooper prof. Greene is! 2 and a half hours straight. This was priceless, thank you SO much for sharing, incredibly interesting content as always.

[@ascender1111]

This is so good. I love Brian Greene. He questions everything he doesn't agree with

[@mikechaisson9875]

Brian Greene is just awesome,Thanks to all those who care to share the knowledge.

[@jaymiller8387]

Science and religion is one of my favorite talks. I personally see it as one compliments the depth and understanding of the other and vice versa much like the to and fro of theory to experiment. Consciousness studies on the cusp of their breakthroughs, quantum mechanics being on the tips of our tongues as we deal with its counter-intuitive nature. This is a very exciting time to be alive.

[@piratessalyx7871]

Me too!

[@donazia]

Thank you Dr. Greene for these series, your guests. I have discovered them and I am embracing the amazing knowledge and insights that overwhelm me with awe and inspiration. It certainly deepens the pondering of this amazing Universe! Gracias.

[@rosacabrero5005]

I am very happy to see you again Professor Greene.

[@cannabisforchrist9589]

That's when I started getting into quantum physics astrophysics and neurology and your shows have been One of my best resources.

[@stephenjones796]

So Great to see you both. The WSF is simply a beautiful mind expansion that I experience!

[@sylvia855]

Hi Brian. I truly enjoy watching these presentations, and especially the discussions with your fabulous guests. I don't have a science or mathematics background but I feel that I can glean some little nuggets of understanding. So thank you! I looked into auditing the course you'll be teaching this Fall semester at Columbia but was shocked to see the $2,400 registration fee. Fortunately for me, I missed the August 14 registration deadline. So I will continue to watch everything you post on the various platforms because your generosity in sharing your knowledge, for absolutely free, is stellar.

[@mariat.lymberis6985]

What a wonderful way of making it all expensive near... Thank you to you both

[@oma2635]

you to

[@ranjitkaur7999]

I request for a video on the road map from an average science student to a theoretical physicist. As a guidance for young minds😎

[@ziemowitmaj7074]

Thank you for committing so much of your valuable time and energy to this. As a side note - thrilled to hear you are vegan, I have switched to the plant based life 8 years ago myself!

[@localtitans4166]

Thank you professor .. you r helping us in lockdown a lot

[@johnkechagais7096]

The answer to the puzzle is to fold space, if you wrap the square into a cylinder then A touches C and B touches D and the length of the road is AB. You can then fold space one more time by bending the cylinder one more time and turning it into a doughnut and making AC to touch BD. In that case the road becomes zero length.

[@rhmcvay]

Thank you for the Live Stream Series and your guests. I'm learning a lot and brushing up on my mathematics. Its ironic that I am reading "Until The End Of Time" to escape the daily reality of our current CV-19 pandemic and economic collapse, not to mention a presidency that ignores science.

[@EastCoastOrigin]

Nearly every president ignores science in some way 😂

[@ggvbayareaoakland5914]

lol I bet you got all the jabs .... did the cdc follow science or the money 💰? haha

[@lukeskydropper]

Wow your comment didn’t age well. Probably at the speed of science. I followed the science but it only led me to stolen money and a vaccin that doesn’t stop transmission. All lies. How do you feel now?

[@lovetwentyfourseven7428]

Amazing to hear y’all speak on spirituality and God in physics and even be open to considering the depths of this in our universe. ❤❤God bless.

[@3xAudio]

Love your videos friend keep it up. Gonna start making more of my own because of these. Hopefully can use your stuff as some inspiration.

[@MMCEnsemble]

Really love these informal Q and A’s. Do you think you are going to create one for the new year? A sort of closing out of 2022 before the semester starts?

[@walterfristoe4643]

As I understand it, there are 5 string theories, two pairs of which are dual to another, and one which is dual to itself. It reminds me of the Platonic solids, in which you have cube/octahedron, dodecahedron/icosahedron, and the tetrahedron that is dual to itself.

[@gd7561]

Brilliant stuff guys!!!! Love it!!!!😀

[@franzculetto5962]

As to the commons of physics and religion, Prof. Vafa seems to be perfectly right: Dogmatism is increasingly shared by both of the disciplines, and what these days is going on with Covid-19 handling exactly fits the hypothesis too, which seems to apply to the lifesciences even better...

[@cannabisforchrist9589]

Hello Brian this Pastor Chris the electrician of cannabis for Christ I just want you to know that God a so very proud of you And the open heart you hold for truthIt's a great gift he imparted to you.

[@sandorkurta9829]

Hello professor Greene. I have been watching your videos here on WSF for quite some time now and with great enthusiasm, unfortunately for me i can only pick up the replays. Living in Germany has a couple downfalls when trying to keep up with whatever happens on the other side of the world. I can only hope that my comment will catch your attention. I have a question that puzzles me. ( Just to be on the same page i am as far from a physicist as a lemon is from a black hole). Nevertheless your talks are the reason why i am asking the question.A typical stellar-class of black hole has a mass between about 3 and 10 solar masses. How massive a star would have to be, to not be able to maintain the nuclear fusion in its core, and instead collapse into a Black Hole. Going a bit further is it possible that the Black Holes in the center of the galaxies have been formed this way in the early universe? Considering that the only element available after the big bang was mostly hydrogen.

[@aaronball4829]

Thanks for sharing

[@wakabaloola]

That’s a beautiful series of examples of spontaneous symmetry breaking, starting at 57:23

[@jacobzwikelmaier6163]

H

[@chaoslord8918]

An additional explanation I would add about orbit, to answer the questions, "How did we get so lucky with the moon's and planet's orbits?" or "Why is the moon's mass and velocity the perfect amount to not fall to the Earth or fly away?" The answer is actually simple; anything that would've fallen to Earth or flown away has already done so. The celestial bodies we see are there *because* they have self-sustaining orbital trajectories. If they didn't, they wouldn't be there.

[@nevaehx4501]

Very insightful views . 🌸💚👍

[@allantaylor420]

Love it!

[@larsfrost3643]

1:14:56 are you using two screens and about 19/20 inch? correct me if i am wrong please :)

[@ahmadaniss4322]

A question for Prof. Vafa: has he come up with string theory as a result of inspiration from Bahá’í writings that states: this contingent world of existence has come into being as a result of vibration of that existed ethereal substance?

[@alexneil394]

My favorite thing about Dr.Brian Green is his un-bias, objective look at things. It’s the mindset I practice to have at all times. Unfortunately much of society simply doesn’t have this capacity, and people get saturated with their own personal or religious beliefs

[@Chexsum]

2021 - where you can learn more at home than at school

[@Chexsum]

basically my whole life hehe

[@MateusMeurer]

2:30:00 Oh but there is. If someone very far is instructed to do one of two options based on the result of the measurement and you need to know what he did. You will have information on what option he took faster than light by measuring the oposite result.

[@skeltek7487]

Nothing new for me, but I still like the wide variety of questions while his answers are mostly similar to mine. Weirdly I end up on this channel after going to bed with something barely related ^.^

[@ralphneufeld3071]

the answer to the highway question. the highway should be built as two isosceles triangles, they will conect either a-b or cd or b-d and a-c but the 2 triangles must be one way only and the triangles will touch each other at the center of the 4 cities. it is the most cost efficient with the given variables.

[@coldwings410]

Fell asleep at my computer and woke up to this. i know nothing about string theory

[@princemonzzzi2174]

Same

[@mazwyd]

Literally same

[@coldwings410]

@@mazwydlol i almost forgot about this. as a sidenote, i need to stop falling asleep at my pc

[@joed180]

Lol same

[@jessemontano762]

Get up. Get away from the komp

[@sunroad7228]

"Energy, like time, flows from past to future".

[@TillMeyenburg]

t/t = 1 in Newton

[@TillMeyenburg]

Relativistic 1 is substitute by gamma

[@sunroad7228]

@@TillMeyenburg Obsolete.

[@marcussandzik5314]

Nice work

[@TheAzad1031]

Excellent

[@randylamonda460]

Regarding the spooky action at a distance and particles spinning up and spinning down could it just be that the observer the mind is affected in that way

[@walterfristoe4643]

We are the universe, becoming aware of itself.

[@randylamonda460]

Sean Carroll did a video on Emergence where he talks about phenomena being described differently are the same. Could that be what is going on with String Theory?

[@JacyJ1]

You’re a treasure!

[@asdfasdf71865]

i need to know if String theory is similar thing as Fourier transform than only converts time space to frequency space. what that other space is in string theory? a string space?

[@sarahrussell9808]

Make a 5th point in the middle of the 4. The you can travel between all points the same shortest distance without backtracking.

[@Gnuddelunke]

We miss you, Pr. Greene. Stay healthy, okay? 😁👍🍀

[@geoffreystearns1690]

I've tried so many of the WSU videos and would really like to understand and enjoy them, but the crummy KZbin audio combined with the difficult accents of many of the star presenters make most of the videos unusable.

[@derekbentley334]

Anonymity within universe after finding the connections having ability to prove. Withholding from science

[@cannabisforchrist9589]

As electrician I became an engineer through the reverse process. Working in the construction test and adjust and maintenance processes for some of the largest And most well known corporations in the world most position probably was project lead for scientific systems Building and maintaining Disney's California adventure park, Socal

[@ReynoldsAudioProduction]

Prof. Greene- here's a question that might not relate to the topics of this video. Just wondering, does dark matter interact with black holes?

[@viewer3091]

Could Space have different shapes at the quantum scale to give it fabric / strength ? ? Some metals are given different shapes to give them Strength / kind of Fabric for certain uses ! Perhaps space at the quantum level is the same !

[@sonarbangla8711]

I wonder why physicists want to detect a string, as we don't get to the scale of 10^-20. GR was true when we didn't detect gravitational waves. The question of verification can be circumstantial. Strings lead to condensed matter physics and quantum complementarity, that made Susskind look inside of a BH. Isn't that enough?

[@larsfrost3643]

imagine a explosion in empty void but the explosion was soo violent that it spread all kind of matters in all directions, probably some matters we dont even know about yet or never will know about exists, the empty void beyond the explosion site of the empty space must be empty on matters or there is a limit of the vast space if not infinite, we people are not advanced enough yet to make the right decision about what is beyond, it is talk and calculations that gives info about what we know so far but beyond that, we are still learning and advancing very slow now.... Atleast we going somewhere instead of being stuck in the same ideas

[@abhijeetghodgaonkar7720]

Amazing yo

[@travisfitzwater8093]

Question: why does clay avoid quartz? Quantum Gravitational Forces?

[@davidbutler378]

Consider Wolfram's Space atoms and Karpathy's (Software 2.0) Transformer nodes in your stringer minds when thinking about Space/Time.

[@Faheemsnotes]

Love you sir from Kashmir

[@JimboJitsu]

if you had a big enough particle... If you could analyze the particle collisions that happen naturally in our ionosphere... you would have the biggest collider possible to work with? perhaps you need to adjust where you are looking from to complete string theory?

[@JimboJitsu]

how many angels can dance on the head of a pin? all of them...

[@silentbooks3879]

Is it true that in order to get to the scale of the Planck length, u need accelerators as big as a galaxy? If yes, could it be even possible to build one? Even for a highly technologically advanced civilization, this is impossible, right?

[@HunnidTheTrapper02]

Not a galaxy, the solar system at least.

[@JCChavz]

If you ever had Cumrun as a professor and he gave you a bad grade...just bring up the moment when he said he cant give string theory a proper grade because the room is still dark after 50 years....there were other doors to “dark rooms” at the time...so at what point do you say, “let’s try those other doors?”

[@garybalatennis]

I am not a physicist but my best understanding is that after 30+ years of top minds working on this theory, there is still no definitive acceptable evidence that string theory (or super string theory) is verifiably true or even close to true. Hence, without established proof, string theory dwells entirely in the realm of philosophy and metaphysics. Now, I do not question that string theory offers brilliant ideas and elegant mathematics, matched with a seductive allure to unify the relativity and quantum worlds with a “quantum theory of gravitation.” At least 2 generations of our best scientific brains have cogitated on it and refined many details. Yet the theory remains only a painfully unproven conjecture - a floating amorphous fuzz without adequate experimental foundation. Indeed, we may perhaps never be able to experimentally falsify or confirm any of its aspects, given the mind-boggling minuscule scales of these proposed vibrating one-dimensional strings. 10 to minus 33. I’m left hollow. I’m lured into thinking 🤔 one of 2 things. 1. We humans might never know the final answer of unification, even with our best instruments. Why? Because we are bounded by our limited perceptions, our stage of brain evolution, and trapped forever in our space-time macro universe with its arrow of time and scales of speed and size. A fish in a bowl cannot know a waterless universe on the outside or “unify” such a reality with his own water world. 2. Or if we still wish to try for potential unification, then perhaps a better avenue is not postulating primordial cosmic strings or even attempting to “quantize” gravity. But rather working the other way: starting with quantum field theory and trying to find an emergent field of gravity (as suggested by Sean Carroll.) Any comments?

[@babyyoda3118]

I think it’s just silly to call it a theory! It’s not even close! And sure there are many smart things discovered by string belivers but there’s been many wise and true insights discovered by religious thinkers but it doesn’t prove the existense of God! They all belivers with strong faith and I support them all even though I’m more of a beliver in the scientific method sort of guy myself

[@mariat.lymberis6985]

Thank you for your comments re Psychoanalysis & String Theory. Most critically the most important contribution of your programs for me is the demonstration of the practice of rational thought as the road to staying SANE by searching for meaning because we need purpose & meaning

[@keramatebrahimi943]

Bravo....your views on religion and science are excellent.scientists should be open to any ideas.where would science be without christian monk studying of nature,or Socrates views or islamic theologians contributions to science.

[@randylamonda460]

The Higgs Field it always reminds me of the idea of The Ether!

[@ahmadaniss4322]

Methafores also can describe the realm of science and realities

[@AdamGNordin]

I'm home now I think 😂 that's a humble statement

[@Tarek_ebn_Afaaf]

"A Mind never at Rest", as the Title of Richard Westfal's Biography of Newton says. Inventing or Discovering & Solving Puzzles Day and Night. This is healthy, I think.

[@eransinbar8628]

If the fabric of space is quantized to units in the size of Planck length in each dimensiin, can we imagine extra non local grid like dimensions between them ?. Can these non local dimensions be responsible for the entangled nature of the fabric of space?

[@billhendrixson6234]

You should read about string theory, what you're asking is kinda-sorta-if-you-squint-really-hard a rough draft of string theory (extra dimension(s) curling in on itself). You can *imagine* dimensions smaller than the Planck length, but its all hairy math to describe it - to begin with its non-Euclidean. That said, the strings in string theory are still larger than the Planck length as well - by about 100 times.

[@eransinbar8628]

@@billhendrixson6234 Hello Bill, I think i was misunderstood . Assuming that space is quantized to Planck length 3D units, I am asking what is the space between these units . can this space be the extra dimensions? if so it can explain the non local quantum entanglement phenomena .its like a grid dimension connecting the local quantized units of space.

[@billhendrixson6234]

@@eransinbar8628 This is beyond my knowledge to answer you with authority, but it is my understanding that space is *NOT* quantized to Planck length units. *Energy* as it applies to atoms, electrons, photons etc *IS* quantized and by virtue of a minimum wavelength (corresponding to the quantized energy) the Planck length is derived. But as far as I know it does not represent some kind of barrier in space or granulated portion of space that cannot be further broken down. Its just that there is no meaningful wavelength large enough to move an electron / emit / absorb a photon below that. I'm sure that I'm not fully getting this here, but I believe the gist of it is right. But what you are asking about sounds vaguely like M-theory or maybe E-8 group theory applied to spacetime.

[@eransinbar8628]

@@billhendrixson6234 The idea that our known physics breaks down when reaching the Planck length and planck time is a strong clue to the fact that the measured fabric of space-time is quantized to units in the size of Planck length. Assuming that a photon can travel one Planck length for each quantized Planck time , can explain the limitation of the speed of light. If that is the case we just defined a new non local grid like dimension (or dimensions) between these space time quantized units. This new non local grid like dimension ( or dimensions) can explain non local quantum un explained phenomenas like quantum entanglement ( " spooky action at a distance " - Albert Einstein). It can be the source of the virtual particles popping in and out of existance in empty space and the source for the unique Higgs particle.

[@darwinlaluna3677]

Going to work and I forgot my keys at my room, it so hard trying to find something in the dark so I turned on the light lol bye

[@SirLothian]

If you uploaded your brain into a computer, wouldn't you still be in your old body? Or do you think that somehow your consciousness can be transferred and only exist in one place?

[@techslugz]

I think your consciosness would probably be trapped in your body if they transerred the 'data', lets say, out of your brain. But the question is, what would you then be able to remember? Anything at all? Would you revert to the mentality of a newborn baby in a full grown body but stil be conscious? Does your consciousness die, dissappate as energy once that body dies? Or, would you remember anything, if so what and how?

[@FormsInSpace]

on the city puzzle. a square + X is the shortest distance. IE a straight line. the H is ridiculous

[@deusdat]

Vafa, the Caligula of string theory.

[@davidrooker1200]

wow

[@walterfristoe4643]

Hasn't the Earth's rotation slowed down since it's initial formation?

[@lovetwentyfourseven7428]

In the highest dimension it would all be known; the potentials of all possible things is known; all sound light motion; awareness or being is to be in a relative position in this field of energy; and Gods position is of course all encompassing. The concept of being arises out of the full oneness that eternal glory of pure metaphysical consciousness.

[@ABetterWeapon]

40:30, Except the moon isn't falling, it's pulling away; or gaining altitude, whichever way you want to phrase it.

[@derekbentley334]

Ask Vafa about building a teleporter because humanity is a living autonomous mechanism with portals to timelines trip wires

[@philipose66]

i totally enjoy listening to you--except that your microphone needs to be 'buffered'--there is a somewhat annoying microphone 'rubbing' sound.

[@walterfristoe4643]

What happens when the expansion of space gets so extreme that even quarks are torn apart inside the protons and neutrons? Will new quarks be brought into existence because they can't exist on their own? And then those will be torn apart and again and again, until at last a new universe will come to be to do it all again.

[@MarshallEubanks]

Most theorizing about quantum gravity envisions modifying general relativity to make it quantum, which leads to gravitons. However, you could go the other way, and envision modifying quantum field theories to make it consistent with general relativity, which leads presumably to an "ultraviolet" limit to quantum field theories. In such an approach spacetime would not be quantized and there would not be gravitons even in theory. Note that there is no observational or experimental evidence for gravitons whatsoever, and Dyson makes the point that there may never be such evidence. as their effects are so weak.

[@deanboyer3825]

Those other super symmetry universes sounds like heaven to me.

[@TillMeyenburg]

Nasa proved outer universes, twin universes. It’s based on a paper of friends about applying energy conservation on creation

[@TillMeyenburg]

And sorry if i am a creatonist

[@deanboyer3825]

I’m a creationist to. You can learn a lot from Quantum Physics. For instance God said “ let there be light” but the sun wasn’t made until the fourth day. The early universe was filled with hydrogen. CERN recently proved that the electron was bound to the nucleus by a photon ( light particle ) so even there was no sun the early universe glowed. Please don’t make assumptions about me. TY

[@deanboyer3825]

Till Meyenburg sorry I thought you were talking to me

[@deanboyer3825]

Till Meyenburg super symmetry is a theory. Meaning multiple universes. Our universe will end as the Bible says “ the elements will burn away” he said his kingdom is everlasting. The theory is those other universes are forever and will not die. Dr. Cumrun mentioned those other universes have Symmetry and are universe does not have symmetry. Did you listen at all ?

[@advitpandey8107]

Topic idea : terraforming earth research to prevent climatic disasters

[@davidbutler378]

How many centuries should we wait until we should look for an alternative to String theory? Of course, some bright post doc is probably contemplating that replacement now.

[@Rookgnar]

They say the universe is to a piece of silt as the piece of silt gets a universe size magnitude to get smaller till you are at the most fundamental super small building blocks. This might have been an old theory

[@derekbentley334]

What is digital TV pixilation

[@piratessalyx7871]

Puzzle answer? My guess intersection in the middle?

[@derekbentley334]

What conflicts of Interest occur within Government with admissions of fact shown seen.

[@avadhutd1403]

Diagonal will slove

[@dombelardo4909]

I see in the body language of B greene that all the years fighting for string theory he is tired and disalusio.... take heart you are not the only one cheers Dom , there is artificial intelligence

[@ahmedelalfy8562]

يمكن فهم التناقضات من حيث أن هناك أكثر من حقيقة واحدة لشرح الكون من خلال فهمنا للواقع المحدود لحاسنا

[@walterfristoe4643]

How far down do the turtles go, Dr. Greene? 🤔

[@cannabisforchrist9589]

About 10 years God gave me the theory of everything after realizing a phrase in the book of Enoch saying all sin would be forgiven except for those that would not was basic programming language he said it's all electrical and show it to me