Exploring Hidden Dimensions with Brian Greene

- Yeah, it's right. - I'm loving it.

All things you never knew you didn't know

about what's going on in the universe coming right up. - Welcome to Star Talk. You're a place in the universe where science and pop culture collide. Star Talk begins right now.

(upbeat music) This is Star Talk. You'll be grasped ice in your personal astrophysicist. Got with me checkin' out, baby. - What's up, Neil?

- All right, this is a special Cosmic queries edition. - Okay. - Because half of it is not gonna be Cosmic Query. - Oh, okay. - Half of it, I'm just gonna be talking to my man.

- Okay, for a moment, I thought you were just gonna talk. (laughing) Up the street, yes. - Professor of mathematics and physics. - And physics.

- At Columbia University. - That's right. - Let it go for crime green. - Now that we're turning champion, Brian Green.

- Oh, thank you. - And favorite, by the way, you know that, right? - Our fans, love you. - That's great, yeah. - We love you because you're a theoretical physicist.

- Yeah. - And, while, of course, data matter, people like just thinking in an unfettered way about what could be true. - Yeah. - We're not true, about the universe.

And there's so many things being bandied about lately, especially in the quantum realm that we thought we'd bring you in for a special recording where there's no time limits on this. We're just gonna talk universe.

Everything cool, weird and wacky about the universe. - No, let's do this. - And you're the man for it. - Yeah. - By the way, when you're not here,

I just sort of fumble over what I know, but when you're here, we got 'em. - Yep, exactly, okay. So let's remind people, your specialty, I mean, historically is, is particle physics, specifically?

- Yeah, certainly can't. For the particle physics side, quantum mechanics, and then moving toward gravity, which of course is the other end of the spectrum. - Yeah.

“- And that's what took me to string theory,”

which is this attempt to put them both together. - Look, look, look, look, look, look, look, look. - Yeah, yeah, yeah. - We're totally gonna get there. - All right, so that means there's no scale of physics

that's out of your reach. - Well, I wouldn't quite go that far. - But, you are kind of covering it, don't you? - Yeah, that's just saying. - That's the thought of the universe.

- What else is this? (laughing) - Well, what's left are the complicated things. - Ooh, like the brain, like the mind, like consciousness, biology,

- Yeah, yeah, yeah, yeah, yeah, yeah, yeah. - You say simple. - You do the easy stuff, the physics is the easy stuff. - You've written the multiple best-selling books. - Yeah, a lot.

- And the one people remember most perhaps was the elegant universe. - Was that your first? - That was my first.

- That was your first book.

- And it was a runaway best-seller. - Yeah. - Yeah, for WWE Norton. - And your most recent book, in 2020, came out just in time for COVID, until the end of time.

- Yeah. - Nice. - Wow, sitting, right? (laughing) - Very personal. (laughing)

- It will just be the end of days, right? - And of days. - So what I like about you is you have a breezy way with communicating your complex physics thoughts. And in no small measure is that

honed in books that are written for the public A, B,

“your co-founder, I think with your wife, Tracy Day,”

former newscar spawner. - Yeah, I think you interviewed me many years ago. - Yeah, I think for NBC. - Could, well, like ABC. - Yeah, yeah, yeah, yeah.

And Tracy Day co-founded the World Science Festival. - Oh, wow. - We did. - Yeah, no, that's just initially it's just being bad as 'cause it was New York.

- Which is the world though. (laughing) I'm not sure if you've realized this.

So I haven't attended as many of these as I have always

wanted, but those of I attended, I thoroughly enjoyed the juxtaposition of the science and the art and the music and just science as culture. - Yeah, I mean, that's what the point. I mean, much of what your work is about

the same thing. People need to see science as part of the fabric of culture as opposed to something off there on the side that you are forced to take in school and then you leave it.

- Right, you leave it behind. And so I think World Science Festival does that brilliantly. - Thank you. - Congratulations.

- Congratulations. - You're in and you're out. It's still going strong. - Yeah, so before we get to Cosmic queries, because we pull our fan base, our donors really,

the Patreon members, and they all know you. So they're coming in with questions. Hot and heavy, straight in. And I worry that I might be asking some questions that they'd be asking.

- Oh well. - Is that allowed? - Yeah, so what? - Okay, so I mean, for everyone that we come across that you have asked that they will ask

'cause they're already submitted, you would just give us five hours. (laughing)

“'Cause that's how much the cost of your Patreon member”

is the entry level, the entry level. - Yeah, okay, so Brian, let's just write off the bat. We hear about the multiverse, okay? On one side of a fan. So then you cross the other side of a fan.

And then we hear about the many worlds, hypothesis, in quantum physics.

- Yeah, they do.

“The idea of a multiverse is the umbrella concept”

for any variation on the theme where our world is not the entirety of reality. - Oh, so that would cover all cases. - All cases. - Oh, yeah, so multiverse or not.

- Yeah, so the multiverse is under the many worlds. - Well, I don't know, many worlds is under the-- - Yeah, the multiverse, the multiverse, the umbrella idea. - Okay, so the multiverse encompasses every single and there are.

- And there are. - There's something like 10 versions of many worlds that have emerged from radically different ideas and quantum mechanics is simply one of those. - Okay, so I was mistaken to think

that the more, there I say, traditional multiverse descriptions. There's one where there's multiple bubbles within our space time. You or that's the inflation area.

- But for an area, you know. - I'm thinking that's the multiverse. - I'm bringing it down, by the way. - Inflation, you bring it down. (laughing)

The affordability, it's a host.

“- The universe is not really in place, right?”

- It's not really inflated. - It's the best price in seven days. (laughing)

- It's never been a better place than the universe.

(laughing) - Oh, so anyway. - So, and then when I learned many words, the world's when I first learned quantum physics, where you needed some way to get out of the conundrum

that you're observing statistical phenomena. - Yes, exactly. - So, catches up on the many world specifically and then tells how that plugs into the multiverse. - Yeah, so when people develop quantum mechanics,

this is now going back to the 1920s and 1930s. - It's a 10-year-old decade. - Yes. - Of quantum physics. - Precisely, which is why I'm writing a book on it.

That'll be published in this decade. - Oh, right out. (laughing) - To catch people up on that. - Yeah, yeah, exactly.

- Yeah, very good. - And the progression of the ideas beginning in the 1920s was to note that a particle, and it'd be specific like an electron. It could be partly here and partly there.

50% here and 50% there. And the question was, but when you look and you measure,

you always find the electron here or there,

you never find it in a blended mixture of being at two locations. - Okay. - And people scratch their head for a long time trying to figure out, how do we transition

from a theory that describes a fuzzy haze of possibilities to the single definite reality when we make an observation or an experiment? - How much of the definite reality was a bias coming out of classical physics?

- Well, you could say all of it because our brains are big and we think they probably operate according to laws that are biased toward the classical, the big stuff. - Yeah.

- And our experimental physics, there's an object, it drops, there's a thing, you move it, there's just stuff that kind of makes sense. - Yeah, exactly. - And nothing quantum physics makes sense.

- And nothing in experience suggests there's anything but one single definite reality. And that was the conundrum. Experience shows one reality, quantum mechanics speaks of many possibilities.

- Measurements in that realm, right? - That's right. So measurements in the realm of the small, somehow seemed to pick out one singular definite reality. But here's the problem, when you look at the mathematics,

which comes from Erwin Schrodinger, you can't transition. - I'm a cat-faint, yes, cat-faint. - But this should have happened. - What a shame.

“- A Schrodinger's cat in the Broadway musical, I think.”

- That would have been really cool. - Well, there wasn't one in the other world. - And this is the point. So Schrodinger's mathematics forbids the transition from many possibilities

to the single definite outcome of experience.

And so people said, "Maybe the transition never happens."

And this is Hugh Everett, 1957 at Princeton, he looks at the equations and says, "We are imposing a classical bias on reality." - Yes. - We think there's a single definite reality,

but according to the math, if you look at that cat, there's one universe which the cat-thalive and you see it alive and you're happy. There's another universe where you see the cat-dad and you're shagrand.

- Right. - And that's the true reality. Neither of you knows about the other version of you. Each thinks they live in a single definite reality, but the bigger picture embraces more than one world.

- Was that other world always there? Was it created in the moment that they had the realization of another realization, the realization of the library? - It's a really good and subtle question. And I don't think every physicist sitting in this chair

would give you the same answer. As I look at the mathematics, I would say, all those worlds in a sense are there. There's nothing really splitting, which is how we often describe it.

The world splits into two. It's more that the description of the quantum realm allows-- - You see the body language and the answer. - You see the body language and the answer. - I know.

- Give me some more.

“- The mathematical description now allows us”

to use the language of one world or another

when that language wouldn't have an applicable before your measurement. But it's not like the world splits and splits and splits. It's all sitting there and some giant, uber realm. - Gotcha.

So does the realization of the measurement? Are you saying that there's a possibility that you're not measuring a definite thing at that moment or instant, I'll call it, in that instant, or are you just seeing that?

And everything else is just still there, but you can't see it because you're looking at this. - See, it all depends on what you mean by you and I hate to be so specific in the wording, because if by you, you have the conventional notion

of a single human being. - Okay. - Each version of me does see a single world,

carries out a single measurement there.

- There it is.

“- If you had a god's eye view which we don't have,”

you would see many versions of me with many outcomes. - Okay, that is so freaky man. - But it sounds like you just pulled that out of your ass. - I didn't. (laughing)

- I assure you. - But that's an important point. Let me just emphasize that when you ever came up with this idea, it was the most conservative interpretation of the mathematics. - Yes, it seems ridiculously unaccountable to have all these worlds,

but the math, if you just take it at face value, this is what it seems to say. (upbeat music) - Hey, this is Kevin The Somalia, and I support StarTalk on Patreon.

You're listening to StarTalk with Neil deGrasse Tyson. (upbeat music) - So let's back up. You and I have chatted, we've hung out socially, and you confided in me that when you were a kid,

and when you were in school. If you picked a book off the shelf, and there were no equations in it, you immediately put it back. - Yep.

- Wow, who does, who doesn't? - I guess I say, who does that? - Okay, a math teacher's favorite kid.

“- That's he does that, every math teacher's favorite kid.”

- Just pat in the math class, so you have a math brain. You have a brain wiring where the math is clear in present to you more so than any words or descriptions that surround it. I don't have a problem with that. You are also dual professor at Columbia in physics and mathematics.

What you just told me makes math the preeminent supreme account of reality, because you're saying the math forces it. And I'm asking you, math is our tool. Why should math that you invented you, anybody humans, force anything?

Why can't I say, there's a different idea that's gonna have different math that doesn't lead to that commundrum. - So if you ask me that question 20 years ago, I would have given you one answer,

which would have been very combative. And I would have been defending mathematics as like the deep truth of the world. In the past 20 years, I've shifted closer to your perspective.

I really do see math as a powerful tool

for describing the external world. I don't see it necessarily as the truth of what's out there, which is why I don't support the many world's interpretation of quantum mechanics, way some of my colleagues do. I allow for it, it could be true,

it's interesting, it blows your mind, but I do not say it's true because it comes out of the equation. - Thank you, okay, okay. That's a very, okay, I'll say mature and advanced.

- Yeah. - Well, thank you, mature and mature and mature stands. - You have matured in the past forever. Because I love me some math, don't get me wrong. Not as much as you do, but when I look at Kepler,

who was a mathematician fundamentally, and he knew about the platonic solids. Do you know about the platonic solids? - I know that they're friends. (laughing)

- The platonic friends, yeah. So if you have polygons, which are flat shapes that have the same sides on them. So triangle would be a probably triangle. - Regular polygons.

I try to go square a hexagon X or something. So if you ask, can you make solid objects with these as its sides? - Right. - There's only five, five, five shapes

that do exactly that. - And where each side is the same polygons. - Okay. - Only five. - Right.

- So one's up here and there. - Definitely. - One's a soccer ball. - No, circle has two different kinds of shapes on it. - Oh, really?

- Oh, so they're not all the same?

- No, no, check next time. - All right. - But it is a way to tile them to figure that you can do it. - So one is a pyramid, another one is a cube. - Cube, of course.

- Right. - And then there's like three others give to me. - Yeah, no deck of heat drawn.

“- And I don't even remember the numbers in the class.”

- Yeah, so-- - And the other one. - Okay, so now, capital, a mathematician said, there must be some divine reason for this five shapes. - And we have six planets.

- There was Mercury Venus, Earth Mars, Jupiter, and Saturn. So he said, wait a minute, if the universe is special and math is special, obviously, they have to be connected. They must be connected. So he embedded these platonic shapes in each other

circumscribing one around the other to see if that gave them the orbital distances of those six planets. Because we have six planets, you have five separations between them.

- Uh-huh.

- You thought that was amazing.

- So he spent 10 years doing this. - And then it was over here. He was like, "Wait, is that my life?" Oh God, what have I done? - But the math is what took him there, right?

- Yeah. - The beauty of the math. - And so that was my lesson that, you know, I ain't knowing there. - But it goes the other way too, right?

Because you go back to, say, George Lemetra. - So he's a priest, a Belgian priest. - Yeah. - He's studying Einstein's mathematics. Finds that the equations, the math says that the universe

should be expanding or contracting. He goes to Einstein, and Einstein says, "Your calculations are correct, but your physics is abominable." This math is not relevant to the world. It's like the platonic solids.

You're wasting your time, and yet in this case, Einstein was wrong. - Oh. - Einstein's math was relevant in the way that George Lemetra was suggesting the universe

is expanding. - Yes.

“- So you have to go, I said it didn't even know his math.”

- Yes, it's relevant to him. - So so Lemetra, he used calculations of Einstein's equations to force upon him a feature of the universe but not even Einstein was imagining. - Exactly right.

- So that's math being bad. - But the math has discovered it. - Yeah. - So it's all just to say that it has to be case by case. - You got me, you got me there.

- Okay. So now, if everybody's doing these quantum physics experiments, all over Earth and it all alien planets, is this a countable number of words? - Yeah, that's a tough, tough question.

It's infinite in any reckoning, but exactly, which kind of infinity, we kind of understand it because we don't want to go into the deep mathematics, but there's a whole structure due to David Hilbert, a mathematician,

who actually raced Einstein to the finish line in general relativity. - Did not know that he was on the track? - Yes, in fact, he published general relativity a little bit before Einstein did.

- Oh. - Is a little known fat? - What's that name again? - His name is David Hilbert. - Damn.

- And the thing that was Hilbert because it's Hilbert's space. - Hilbert's space. - Tell me about that, yeah. - But in this particular story, Einstein had visited Hilbert in June of 1915,

showed him everything that he'd worked out for 10 years, then Hilbert took at the final step and published before him. In the end of the day, Hilbert said, "No, no, it's your theory. "It's your theory, Albert."

- I am not trying to take it from him. - It's very cool. - But he did publish a little bit before him. - Yes, you know, he would not have published Einstein not visited him.

- Yeah, he would have known anything about this. - But the point for quantum mechanics is that there is this thing that you made reference to Hilbert's space, which is the mathematical structure within which all these worlds live.

- And we understand the math of that pretty well. - Oh, no, yeah. - So why does it need a mathematical structure in which they live? - Well, well, if you're going to describe things

with rigor mathematically, you've got to define things. You've got to have the operations to be able to categorize the ingredients and remarkably this space that Hilbert introduced

has just right mathematical properties to be the space in which all these worlds live. - Does it suffer from a completeness feature? - You know, everything, yeah. - A completeness theorem?

- Yeah, girdle.

- Yeah, so, so, yeah, so girdle had a very powerful result

that any basically sufficiently complex mathematical structure will have true statements that can't be proven true within the axioms of that structure itself. - So it just has to be asserted.

“- It has to be asserted or you have to somehow intuit it”

or feel it or in, you know. - In the general relativity, it sounds a little suspect. (laughing) - Well, but the deep question is, are there interesting physical features of the world

that would be undecidable in this girdle in sense? - That's what I'm asking you. So, is there a feature? - I don't know the answer. - In general relativity, where you part the curtains enough

and then there's just some assumption you had to make. - Yeah. - And everything issues forth from that. That you cannot deduce from anything that follows. - Yeah, I mean, to surely are axioms

within these theories for sure.

but can't be proven within this structure itself?

I don't know, because when you look at girdles proof, the kinds of things that are undecidable are very contrived. You know, the things like, you know, the set of all sets that are not subsets of themselves.

“You're like, well, does that ever come up in the real world?”

- Right, right. - Or the barber of civil, you know, nobody shaved themselves, but then like, who shaved the barber, who's, you know, so they're all very self-referential.

And it's not obvious that they have direct relevance that things that we could measure. - But it's still an important discovery. - She's amazing. - She's amazing.

- Yeah, she's amazing. - And it's thing about the closest I got to that barber, - Yeah. - was I used to read Brain Tees of Books when I was a kid. - Okay.

- And so one of the ones you kind of were town only two barbers. - Yeah. - And one of them is just completely messy. And the guys unkept and he's at,

and his hair all they just--

- But that's town looks amazing.

- Alright, and then there's another barber. Where he's clean, shaved, and he's, everything's neat, so which barber do you go to? - I'm going to the messy one 'cause he clearly does the other barber.

(laughing) - Exactly. - Somebody cut his head down to the barber. - That's the guy. - That's closest I've gotten to the barber.

- Good. - So with the many worlds, now connect that up to a multiverse. - Yeah. - It's just a declaration.

It's a multiverse. - Yeah, it's kind of-- - It's one flavor of multiverse. - That comes directly from the math of quantum mechanics. And the natural next question is,

can you prove it? - Can you demonstrate this? - It feels less real to me than the multiverse I've read about. - Yeah, no, I understand that feeling

because our consciousness feels singular. And this theory is saying there are many individuals in this larger realm that have your memories, that have your experiences. And they only differ from you

that they saw the cat dead and you saw the cat alive. - And that's just-- - And let me ask you this with respect to the cat to this.

- Give me a second to like--

- All right, just tear up. - See, I watch a lot of Rick and Morty since he was about to me. - That's about to me at all. - I just learned--

- Yeah, yeah, yeah, yeah, yeah, yeah. - Of course it works that way. - Yeah, yeah, yeah, yeah, yeah, yeah, yeah, yeah, yeah. - But this other me, that's me identically, except we observe the different outcome of the experiment.

- Yeah, and then from there, you continue to diverge because we know that little changes right now over time can turn into major deviations in your lives later on? - 'Cause I've seen in several films,

but let me pick one in specifically, H.E. Wells, the time machine. I'm reference, I didn't read the novel, but I saw the movie when I was in from the '60s. And the guy, the main protagonist,

be friends of women who shortly after they have this encounter, she's like hit by a truck. She says, "Well, I have a time machine. "I can go back and go back." - That's interesting. - That's interesting.

- Oh, don't exit the park this way, go the other way. She goes the other way and something else hits her and she does. - Yeah, and the safe drops are in her head. - One handle, and that will even better.

- Right, right. - And so after two or three iterations of this, and another one she's mugged and killed, he concludes that it was just her time. - And he can't change fate.

- Can't change the outcome. - Okay, but when I saw that, I said, the molecules of air that are around her are in a different place because she's displacing these molecules relative to these.

That's a different universe. - Yep.

“- I'm not gonna look at these as just this is the only thing”

that has to stay constant. Tell me about all the other little things that change relative to the big thing that you notice. - Yeah, so in that version, I think you're right. If the person could really go back and time, change things,

I think you would get a different universe. I don't know of any overall law that says certain major events or minor events have to be preserved. But in the quantum mechanical version, it's completely different.

If you take on board this idea, you are committing to different worlds where things are rapidly different. - Right, definitely. - One she would live and the other she would die.

If they are allowed, if these outcomes are compatible with laws of physics, then they will happen in one or more of the worlds in the quantum mechanical multiverse. - Wow.

- All things compatible with the laws of physics are realized. - There's a real, wow. - That's pretty wild, man. - Okay, so, but, all right. - I love that.

- Wait, wait, stop. (laughing) - I love that.

“- Here's the only thing that I can't get with that, all right.”

In that case, how do you reconcile infinity or an infinite number of worlds? Let me get there. - Okay. - So watch, we went from the many worlds hypothesis

where it is exactly me, but I'd look at a dead cat instead of a live cat or vice versa. In the multiverse is to which I've grown accustomed, there's possibly an infinite number of them.

mostly myself, except I have a goatee,

“or I'm evil Neil, instead of friendly Neil.”

- So that's not an Neil. - You're Neil, who believes in tarot cards. (laughing) - Well, so that's not a many worlds Neil. That's just another statistically configured Neil

out of the random molecules in that universe. - Right, but the beautiful thing about the quantum mechanical multiverse is that when you study the possible worlds that can emerge, they embrace effectively anything

that would have a non-zero chance of occurring. - Okay. - And that's anything in effect that's allowed by the laws of physics, so if the laws of physics allow you to have a goatee, then there will be a world

in the many worlds where you do have a goatee. - Right, but in that world, that's a different me looking at the cat because the dead cat live cat version of me, they each have a goatee. - Yes, so if it's a very minor event

like doing a single observation, usually a single observation can't yield that your radical change immediately. It'll be you without a goatee and one, you without a goatee and another.

But then if you wait long enough and you accumulate the huge number of ways that you could have gone left, you could have gone right,

“you could have gone up, you could have said yes,”

you could have said no. When you put all of the cops running in the attic and all of the different worlds. - Yeah, now one of them results in you having a goatee because that came along

for the ride in that particular moment.

- So here's what I want to know.

That's the infinity. - Yeah. - Are there a finite number of particles in this universe? - They're a finite number of particles in the observable universe.

- But the universe could go on - You could go on forever. - Okay, then that, that, that, that, - Remember the question? - We don't know. - Yeah, because my point is

then that means there's a finite combination of all these particles that could create these worlds and so how do you get to infinity? But if the universe goes on and on and on, then yeah. - Yeah.

- Yeah, there is no, there's no end. But even with an infinite number of universes with the same number of particles, you just can figure them and keep... - Well, my point is this, can you reconfigure

a finite number of particles to get to infinity? - You can, because it's not reusing the same electron or the same proton in one world and another. - Okay.

- It's a realization of that particle in a different configuration. - Right. - And that's, it's not like a conservation of particle numbers. - Yeah, yeah.

- Yeah. - So God, wow. - So, I used to be into, yeah. - I used to be into big numbers and I still am, but I haven't stayed with it and one of my favorite big numbers was skews numbers.

Do you know skews numbers? - I don't know, skews number. - I don't know, use 10 to the 10 to the 10 to the 34th power. - Okay, and if you, if you play that out. - Yeah.

- You get the total number of configurations of all the particles in the universe. - In the universe. - In the universe. - Right, so it's, as though if the universe were a cosmic chessboard, it would be the total number

of possible moves. - Right. - 'Cause you're not counting objects at this point. - No, you're counting, you're counting things. - Yeah, counting things.

- Combination. - Yeah, I would, I would get a different number if I was to use the entropy of the observable universe, which we can calculate from the dark energy. I would get a 10 to the 10 to the 120.

- Okay, that much, much from 10 to the 10.

“- Yeah, so I think it has to do with whether”

you're only looking at material particles at, yeah. - Yes, yes, it is. - versus the energy that. - Oh, no, of course. - Yeah, the energy is all in there too.

- Yep, yep. - Yeah, this is just counting up the physical particle. - Sure, that makes sense. - Okay, cool. - So do we actually know the amount of dark energy

that's in the universe? - Well, we measure it. - We do measure it. - We do measure it by the rate at which distant galaxies are accelerating away from us.

- Exactly. - And it's this ridiculously small number. - Okay. - In the units that we typically use to measure these things. And that translates into this particular number

for the entropy, the number of states that the universe can possibly be found in. - Right. - Okay, that makes sense. - But the question you asked before, if we could return

for a second, because it is issue, this issue of infinite number

of worlds. - Yeah, wait, wait, wait, wait, wait. - Before you get there, I just want to remind people that. - Exactly, yeah. - When you say, if there's a chance something can happen,

no matter how small. - Yeah. - You multiply that very small number by infinity. And you get a real number. - And you get many worlds.

- You get many worlds. - One word that could write that small probability thing could have. - Exactly. So the infinity that you're where you're about to go, right.

Helps bring out of the depths the statistically unlikely possibility. - And that to me is the Achilles heel, or a potential Achilles heel of this approach. And again, I have to say, different people in this chair,

they will say different things. But the issue that many of us have taken with the many worlds is just that, if an outcome has very small probability.

- That should mean it's very unlikely to happen. But from the analysis that you just gave, no matter how unlikely it has to happen, it will be realized in some world. So what does it mean to say something is unlikely

if your shore is gonna happen in some world? - Exactly. - Yeah, yeah. - Now, it's like having a drink. - It's five o'clock somewhere.

(laughing) - So we encounter this in astrophysics where we talk about supernovae as being extremely rare event. Okay, not all stars will go supernova

“and even high mass stars, some go black hole, right?”

- It's rare, right?

- However, the galaxy has a hundred billion stars in it.

There's a hundred billion galaxies in the universe. So when people realize, if you have enough of a sample size, you could deliver every single night supernova into your catalog. - Right.

- It's a rare event that happens often. (laughing) - That was initially kind of hard to explain to the public. - Yeah, yeah, how do you get that? - Yeah, so we have a version of that

in the Quantum and Chemical Multiverse, but it is more of an issue because you're guaranteeing the existence of a world, a whole world filled with the observers and experimenters who are guaranteed to see the most unlikely things

on a regular basis. - Right. - And that is an issue. Now there are some people who work on this who say we've solved that.

Just read our paper, read our book and they do some interesting mathematics. I am not convinced. And that to me is where the issue is. - Okay, interesting.

So let me ask, I think we chatted about this over once a few moons back. - Thanks for inviting me. (laughing) Oh, it's in your inbox.

(laughing) (laughing) And forgive me, I might have had this conversation with Brian Cox, so I'd say yeah. - Forgive me, because you're my favorite physicist.

It's out there, but so do you feel bad that I have another physicist who I have? - A little bit. (laughing) - So I learned this early,

because I said I was into big numbers when I was a kid, that there are levels of infinity. - Yeah. - I think they're at least five. - I mean, you can keep on going.

- I know, you buried the lead, guys. Now you gotta explain that. You can't just say that. - You weren't at the ones. - So it's the one.

- Should I? - That there are levels of infinity. - Yeah, yeah, yeah, yeah. - But you weren't at the ones. - Do you know how counterintuitive that is?

“- You weren't at the ones, so do I have to drag you behind us?”

- I know man, I'll take a doggy back. - Okay, 'cause that's crazy. - Okay. - We'll explain that in a minute. - All right, go ahead, so I kept thinking to myself

that you can have an infinity of universes, and that would not be a big enough infinity to exactly reproduce me, and that you would maybe need it higher levels of infinity to get all the combinations that people like

to talk about in the multiverse. - Right, right. - So does it require the higher levels of infinity? - You know, the most straightforward answer would be to say I don't fully know, because I don't know

that science understands you and put you in my life well enough to say. - You know what? - Just said he said I could be so simple. It's right.

- The trivial to copy it. - But I don't know obligates to understand you. - But if you take on board the idea, that you are just a collection of particles that are governed by the quantum mechanical laws,

if that is something you're willing to accept, then there is enough room inside of Hilbert's base and the quantum mechanical infinity to reproduce you and to reproduce every variation on you where some of your particles--

- Variation conceivable. - Yes, yes, every variation allowed by the quantum laws, which simply-- - You've written to me that that's a tooth cavity

'cause I've never had a cavity.

- If that's compatible with the laws of physics, and I think it is, then yes. So non-dental plan Neal. (laughing) - Is it the Neal with no dental plan?

If that's within the bounds of quantum mechanics-- - We've got physics, no performance. - That's a physics, don't forget it. - Then we got enough-- - We got enough, not matter.

We have enough material to make sure that I have. - I don't need the higher levels of infinity. - No, no. - Okay, absolutely. - Okay, so now let's catch up, Chuck,

'cause everyone else out there knows about multiple infinitesis here. So-- (laughing) (laughing)

- Please catch me up. - So these are levels of infinity.

“I think there's a Hebrew letter associated.”

- Olive. - Olive. - Olive zero is a traditional infinity. Olive one, two, and three. So we don't have to do all five.

Just get me to like the second infinitesis.

- Yeah, so the simplest one is the one that comes to mind immediately. You just count the numbers. One, two, and three. - And they just go--

- And they just go on. And that's the simplest principle, but then if I ask you, how many numbers are there between zero and one? - On the number line. - Oh, wow.

- Now you said yourself, well, can I numerate them? Can I put them into a correspondence with the counting numbers and just list them? - Because if you correspond-- - Am I not good?

- But I'm still going to do this in 20 seconds. - Wait, wait, wait.

- Yes. - I'm kind of dividing. - You aren't, you could say, well, let me put a dot in the midpoint, call that one. And then a dot in the midpoint between it and zero.

And call that two. You won't cover all the numbers. - And there's a wonderful--

- Never reads one, because it'll always be a place

where I can, once again, put something in between one and where I am. - It's another way of saying it, but canter had a powerful argument that's actually pretty easy to understand we need to write it out for me to show it to.

But he established that if you try to enumerate the numbers between zero and one, just list them, you will fail, you will always miss some. And therefore, there are more than an infinity of numbers between zero and one.

And that next level of infinity is the version that Neil was referring to. - Oh, wow. - Yeah. - I was giving my bag, I'm going to leave my weed.

(laughing) - Okay, so you just skipped by it. And I wanna make sure we can contemplate it briefly. The one way to know which infinity is bigger than the other

is you correspond them to this, exactly.

- Right, so you can say, because this is kind of a little freaky, the odd numbers is the same size infinity as all the counting numbers that include odd and even, of course, how do you get that? - Well, you know, you could take any given number

and say, multiply it by two and add one to it. And in that way, you're certainly getting odd numbers. - You get not number, and now you've lined up, you've lined up the numbers one, two, three, upward, and the list that it corresponds to are all odd numbers.

- They all just go up. - Yeah. - Damn, that's wild. - Wow, math is kind of cool, yeah. (laughing)

- Oh no!

“- Okay, and just to taste it, if I remember correctly,”

I'll have two, go into another dimension, the number of lines in three-dimensional space is a bigger infinity than the counting numbers on a number of-- - Yeah, that may be a way of saying it. I'm not sure if there are many ways of expressing these

infinities, and there's actually a kind of almost an algorithm that allows you to start to build up this set of infinities, you can look at subsets of subsets and things of that sort of look at power sets as it's called. And so it's a astoundingly strange idea,

which is why mathematicians who thought about this in the early days-- - You're all in a style one's right now. (laughing) (laughing)

- I'll never get to one, I'll never get to one,

I'll never get to one, I'll never get to one. (laughing) - That's so rude. (laughing) So, and if you go to higher dimensions, in principle,

does that take you to-- - Not necessarily. - Infinity? - No, I mean, if you start to look at the number of points in the plane, it's a, you know-- - What's the line with the points?

“- Yeah, so you have to be fairly careful.”

- It's sophisticated in how you build up these infinities. - Okay. - But for our purpose, there is this thing that we've made reference to, it's a bit abstract, this thing called the Hilbert space. And we understand it reasonably well.

It's an infinite dimensional space that David Hilbert developed, but we understand it well enough to say, it does have enough room to embrace all the quantum mechanical space. - It has infinite dimensions. - Yeah, yeah. - Yeah, yeah.

- Yeah. - Yeah. - And within that space, in principle, there is a place that describes you. - All right, so now, I am however improbable in the configuration of atoms and molecules,

even here in this actual reality. - Okay, so have you thought much about whether or not something can exist and whether or not it does, the likelihood of-- - Yeah, and it's a mind-blowing thing.

- Tell me. - When you think about the sequence of steps by which you came to be. And I'm saying, let's go to your childhood to your birth. Let's keep on going further back, your grandparents grave. Let's go all the way back to the big bang.

And if you look at the sequence of steps from the big bang-- - Let's just go back to the big bang. - You do, I'll show you. - We all do right. - We all do right.

- How we get here. - You know, we have collections of particles that are configured in a certain way, and they have a history, and it's that history which resulted in them being in the configuration

that's called Neil deGrasse Tyson. And if you look at the sequence of quantum steps, each of them are incredibly unlikely in the collection of those sequences is innumerably huge, and they're incredibly unlikely,

and yet here each of us are. - So what do I do with this information?

“- Well, I think it gives you a certain--”

- What is your special? - Well, you know, if you want me to be a little bit sappy, you know, I think it inspires a gratitude, the unlikeiness of us being here, kind of being at all, and therefore is a certain kind

of thankfulness that the universe turned out

look around and appreciate everything.

- That's wow, so now I'm looking at that, and immediately going back to our previous conversation about the two observers, okay, with a deck cat, with a deck cat live cat, and the many worlds. What you just said, can negate that,

meaning that also there are an infinite number of worlds, whether it's just no Neil, and then there's an infinite number of worlds, whether it's no cat, and then there's an infinite number--

- You're absolutely right, and I think that's one of the lessons if you take the many worlds approach to quantum mechanics to heart. It is saying that clearly we are compatible

with the laws of physics, because we're here, existence proof. - Right. - And if you take them many worlds seriously, then we were guaranteed to live in some world

in this grand collection of many worlds. Now, in some sense, this world is incredibly unlikely within the panoply of possibilities, but you're right, in that sense, we were an inevitable outcome of the quantum laws

because we are allowed by those very laws of physics. - Right, but Brian, I have a more anchored version of what you just said, that I credit to Richard Dawkins. - Yeah. - If you look at the total possible genetic combinations,

that will make a human being, a viable human being. - Okay. - It's a stupofionally large number.

- It's like four to the three billion, it's not there, right?

- Yeah, it's great, it's great, it's 10 of the 30th power,

“it's high, but what matters is not even how big it is,”

but it's vastly larger than the total number of people that have been born. - All right, yeah. - Plus or minus, it's about 100 billion, okay? So, Dawkins' point is, we should cherish life because most people who could ever exist

don't ever even be born, that's right. - Yeah. - So, we can be sad that you die, but he describes those people who die as the lucky ones, who got to live in the first place. - Because you can only die if you got to live, right?

- And for me, that's a little more anchored than he. - Yeah, but to take the point we're saying before, if the multiverse version of Quantum Mechanics is the right way of thinking about it, they did.

- Then they did live, if their genetic sequence was compatible with Dawkins, so, you know,

so don't feel bad for all those little swimmers

that didn't quite make it to the age. (laughing) (laughing) - The sperm, you're talking about that? - That's exactly.

- So, Brian, I get this question often, surely you do as well. If we live in a multiverse and we're just one of an institute, where are the other universes? - Yeah.

- And you're gonna cop out and say,

“oh, they're in the infinite dimensional Hilbert space?”

- Well, it's easier to answer that question for other flavors of multiverse, like the inflationary multiverse that you made reference to before, because-- - That's the simplest.

- As a simplest one to picture. - So those are the places you see in our own, we're in a bubble, right? And there's another bubble over there in the same sort of space and the same construct.

- Construct, in the same construct. - Yeah, because according to inflationary cosmologies, you're making reference to, there was an energy field that gave rise to a pulse of gravity that drove our big bang, but the math shows that it would not have used up

all of that energy in the process. Someone would be left over, the leftover energy would yield another big bang, and it would not be fully used up, yielding another big bang. And so these distinct big bangs,

as you say, would give rise to these sort of bubbles in a big cosmic bubble bath. - Okay, so that's in one construct. - Yeah. - Okay, but now, there are other variants

- Yeah, multiverse is where it's sort of separate. - Yeah, when you talk about the quantum mechanical multiverse, it's much harder to think about where those other worlds are. They're not kind of adjacent to our space.

It's a more abstract place that they inhabit. And I'm gonna try to avoid using the word "ilbert space," but that's the mathematical architecture with in which we can see these worlds existing. I can't picture, I can't picture where these other worlds are.

“If you ask me, do I have a mental image of them not really?”

- Okay, so that's a mathematical architecture. - Yeah. - Can I divide an experiment that would show that they exist? Is it, can I wormhole to them? - Yeah.

- Do I even want to wormhole to them? Because quantum physics might give you slightly different laws of physics. - It's unlike the laws of physics are different, but the properties of ingredients

might be different in principle. If there are sufficient quantum mechanical processes that could yield worlds with those distinctions. But I don't know the experiment, and I don't think anybody does.

Where, when you can say, if we could get this in this result, we would establish that the multiverse. - You tell me that other universes gravity can leak out of them? - Yeah, so that's another variation on the multiverse that comes from string theory, which we can talk about.

- But just to press it, what we might talk about,

in this version, our universe is sort of like one piece of bread in a big cosmic loaf, and the other slices of bread would be the other universes. So they would really be hovering next to us just displaced in an actual additional dimension of space.

And then your right gravity can influence permeate that space. - So when I was having my little ayahuasca trip, I met these beings that were in betweeners, and they were in between dimensions. That's where they occupied.

Okay, I feel so silly. - But they were listening. - Okay, they explained that, they talked to you. They did, they talked to me. And they were two dimensional beings

that I could see in three days.

“Sounds creepy, but that's the only way I can explain it.”

Okay, and they explained to think of it like an infinite number

and they called them dimensions, going out,

and going up, and going out. But to think of them as a deck of cards, slapped up the way we see a deck of cards, we see it as one deck of cards, but it's not. It's however many cards are in that deck.

And until you separate them, that's when you can see the different things. That's how it was explained. - So this is almost the reverse of that. It is if we only see one card in the deck.

That's our world, but a God's eye view would see the entire deck, which would have the other card. - And that's where they see it. I see it as the one card, and they were explaining that they see it as the deck.

But anyway, I'm just, I shared that with Jan 11, and she was like, that's pretty interesting because in this game we some speak that I didn't understand. - Yeah, it must be the same basic idea. Actually, we just wrote a paper on the so-called brain

worlds in string theory.

“So this is something short for membrane.”

- Yeah, yeah, yeah, yeah, yeah, yeah, yeah, sure to say that.

- It's amazing. - So I never took a satin by this.

In graduate school, I'm taking astrophysics classes, but I wanted to take more physics. And a physics class I never took was Feel Theory. - Yeah. - A whole course on Feel Theory. - And you can come to my class one of these yeah,

I've taught Feel Theory a number of times, yeah. I'll let you know next time. - And it's cool, and I sit in the back. - Yeah, yeah, yeah, yeah. - That's not intimidating.

- What is this? - I'm gonna fail, I'm gonna fail, I'm gonna fail. - No, but I'm not in a position to calculate or even really know why gravity can escape, but not the electromagnetic wave.

- Well, I'll give you a quick, an demonic sort of to think about, which is so instring theory. Gravity is communicated by a string that has no ends. It's a closed loop. The electromagnetic force is communicated by photons,

which instring theory are strings that have two open ends, and those ends are anchored to the membrane. They can't escape the membrane, but because the gravity particle, the graviton has no ends, just a loop,

it's not anchored, it can get off and travel between those words. - Wow. - Is that a description that would be in the book, string theory for dummies?

(laughing) - It's there, no doubt. - Okay, so if that's the case, why isn't what we measure as dark matter? Just gravity leakage from another slice of breath?

- People have made proposals like that. If your dark matter is meant to explain the gravity that we know is there, but we-- - Really dark gravity. - It's dark gravity.

- Yeah, so if you can have some source of gravity that you don't literally see, it's a candidate, and so people have put forward it's hard to make this idea really work, but in terms of its general possibility, sure.

- Could the bedding person, if you're into bedding, what an outcome would be, an exotic particle is sort of the bedding man's solution to. - Yep. - And that's put forth by particle physicists.

- Right.

“- If you're a hammer, you're a little bit of bias, right?”

So I'm liking me the gravity spillage. - No, I like the idea. It's in detail, it's only when you get down to breast hacks that it's hard to make this really work. - All right, so let's pick up the baton here

on strength theory. - Yep. - Okay, where I'm a little older than you, but we came of age with enough overlaps that I can speak of the 1980s as a time

where strength theory was burst and started taking off with some vigor. - Yep. - All right, everybody, I spoke to you at the time. And at the time, I was at the University of Texas,

which had its share of strength theorists. - Yeah. - And Steve Weinberg, right? - Steve Weinberg, right? - A graduate of my high school.

- That's true. That's true.

- Yeah, I agree. (laughing)

- So Steve Weinberg, a Nobel Laureate in physics,

a cosmologist, you know. Hey, yeah, so I ask people, so when you guys gonna figure this out, 'cause you're trying to unify quantum physics and the large and the small,

and it's almost there five years in five years, we think we'll do it. So, you know, 10 years later, well, when you're gonna do it all in five years, whatever, 20 years later, all in five years,

the problem is hard, it's a hard problem, but we're on it. And so I've never heard convergence in any conversation about strength theory, landing where it had intended. - Yeah.

- A, B, could it be?

“And I think I've said this on stage to you.”

And you didn't jump up and try to hurt me. Could it be that all of you are just too stupid to figure out the solution? And let me say that more carefully. Are we awaiting the birth of some 21st century Einstein

to see the solution here that none of the rest of you are? - Yeah, yeah, it's all possible.

First off, I would never have said five years back then.

It's a very dangerous thing to make a prognostic conversation. - This is a good question. - Yeah, there's huge enthusiasm. But look, strength theory has done miraculous things since the 1980s, and I'm happy to sort of list the achievements,

but you're right, it's not done the one thing that ultimately matters, which is make a prediction that we can test, you know, at a particle collider and determine whether these ideas are correct and it could well be

that we just don't have the brain power to get there. And it may not be that we're awaiting the birth of the next Einstein. Maybe we're just awaiting the next configuration of AI that may be able to do what we as individuals

have not been able to do. I do think there's a real possibility of the nature of research changing next five to 10 years.

“- Five, five, five, six, five, six, five years”

earlier than you did. (laughing) I did it with that.

- This one I'm willing to stick with though,

because, you know, I gave an example. I mentioned this paper that I wrote with Jan 11 that you make reference to. - Is this the local bread paper? - No, it's the, we wrote a handful of papers together.

This is a more recent one. And I wondered, could chat, get the answer that took us a long time to get, if I treated you. If I treated it as sort of a good graduate student. So I just gave it a few prompts

the way you would to a graduate student to not give it the answer. And it couldn't look up the answer. We hadn't yet published the paper. And within a half an hour,

it was able to reproduce the results that took us months to get. - Oh my gosh. - And so it's as if you have the greatest graduate student known to humankind, even an army of them

at your disposal. And that's now. - This is a hologram right now. (laughing)

“- You know, it's an A-A, I'm not even here.”

(laughing) - So what is it going to be like in five years? You know, it's both exciting and scary. - I have a colleague, yeah. - Who has a similar story regarding his research

where he was prompting chat to think about a problem. - Yeah. - And it solved the problem that he had not been able to solve. - And actually solved it. - Yeah, actually solved it.

- Wow. - In the sort of, you prompt a really good graduate student in just the way you're describing. - Right. - But catch us just on why the whole field is called string theory.

- Well, the basic ingredient is a filament that looks like a tiny piece of string. The idea is that it can vibrate in different patterns. And the different particles that we know in love electrons, quarks, neutrinos, and so forth.

- The fundamental particles would each correspond to different vibrational patterns of this new entity called string. - So the string becomes the fundamental particle. - Yes, and it's a unity because it's one thing

that can manifest as many different things, depending on how it's vibrating. - Which is for people who like unity, this is a beautiful thing. - It's a beautiful thing and it goes even further.

When you look at the math of this, you find that not only does it unify all the particles, but it unifies quantum mechanics and general relativity. - It allows the small and the larger the base. - Do you do that for free?

- It does that for free. It just comes out. I'm telling you, you look at the math. - That's a nice fact. - Look at the math.

- You look at the math, right? You stare at the equations and out pops, Einstein's equations from general relativity. - Wait, to whom does it pop? (laughing)

- Who do you have to be for instance? - Yeah, pop out. So I had not fully embraced that reality. - Of string theory. So I'm delighted to hear that.

So that was part of the enthusiasm that people would have then had. - That was part of the all major obstacle. - The major obstacle is that the theory is mathematically complex and the pathway

from the fundamental equations to physics we can see in the laboratory is fraught. It's difficult. It's tough terrain to cover. And so we've been developing mathematical tools

We've made progress on black holes.

- The 80s was 40 years ago. - I guess you're right. Oh my God.

“String theory has an answer to that question yet.”

- 40 years ago. - 40 years ago. - For that was the 1940s. - Yeah. - I'm with you on that.

- You know, so we've been for 40 years. (laughing) And so we've understood things about space and time and gravity and black holes which I didn't think we'd ever understand.

- Right. - In my lifetime? - Yeah. - On the flip side that we've not understood the things that I thought we would have understood by now,

which would be make a prediction for what's going to happen at the Large Hadron Collider and let's check it.

And so it's an interesting thing that we've made headwind.

The very things I thought would be too hard and we've not made headwind the things that I thought we would be able to reach by now. - Right, so I don't like making arguments and other people make just for the sake of bringing

the argument to you. But just let me just do that. - Let me do it anyway. - Let me do it anyway.

“So, String Theory has not been without some criticism.”

- Yeah. - As something that is consumed the ambitions of graduate students and faculty and promotions. - Yeah. - And so it's a field without a prediction

that can be tested yet it had such a presence on the landscape of physics departments. - That might have smothered some other branches of physics that might have been a little more promising. - You just comment on that.

- I sound like jealousy to me. (laughing) - Well, it's an interesting argument because though very graduate students and junior faculty and senior faculty who this person who's making

this argument fears may have wasted their time, not looking at something more promising, you gotta assume the really smart people because of the very people you think who could have pushed the frontier of another field.

And if that's smart, allow them to make the choice for where they think the greatest promise is. - Yeah, so it's not as if somebody was like putting the bag over their head or putting a gun to you. They were looking at the ideas throughout.

They're found the String Theory at a guy, he is so compelling that they were willing to take a chance. And that chance may not pay off in our lifetime. - And tell me about the 10 or 11 dimensions? - Yeah.

- Because that sounded very cop-outy. - Well, I can't explain this. - I mean, it's throwing a dimension. - Good, good, good. - Another dimension.

- But yeah, another dimension. - You need the dimension. - Good, good, good, good. And I think if I articulate this correctly, I think you'll have the same epiphany

that you did about gravity coming out of String Theory a moment ago.

“Because again, you wonder, do you have to put general”

activity into String Theory? I said, no, no, it just comes out for free, which is a beautiful thing. How about the extra dimensions? They come out for free too.

They're forced upon you by the equations. - Oh, you don't put it right. - That's not at all. - That's not. - That's a force. - Literally, this is not a joke.

There's an equation in String Theory. That basically looks like D, the number of dimensions. - Minus 10 times as complicated factor, must be equal to zero for this theory to be self-consistent.

The complicated thing is never zero.

Therefore, D minus 10 must be zero. Therefore, D must equal 10. That is where the extra dimensions are forced upon you by the equations. - Yes, that's insane.

That's pretty cool, though. - Yeah. - I mean, that's, so we don't experience them. Why? - Because we believe that they're probably too small

for us to see with the naked eye. - Or for more dimension means. - It means that if you head off in a given direction, you kind of return to your starting place. So quickly, you can think about a straw, right?

A straw has a long dimension that we can easily see, but it has a curled up circular dimension. And if that's a circle, of course, we can see that with the naked eye. But if you made the circles--

- They're circles with through it. - Yes, but if you made that circle smaller and smaller and smaller at some point, you won't see it at all, and you'll think it's just a line. - You've hidden the extra dimension.

- So all the other dimensions are hidden. - We think that is one explanation for why we don't see anything. - In fact, I was gonna call the elegant universe hidden dimensions.

That was the title I was playing with back 25 years ago. But anyway, yes, exactly. - All right, so you're hiding the dimensions from us. - Yes, but that is by hand. So when we look at the math, the equations don't tell us

these extra dimensions are really tiny. Instead, we're doing what you accused me of perhaps on other things, we're saying, how can we make this theory compatible with what we see, let's envision

that the extra dimensions are really small. - Got it. - Okay, so a string is 10 dimensions. - A string is living in a 10 dimensional space. - Okay, now, why would a string be fundamental

- Yeah.

- And dimensions are just dimensions.

Why can't it be another reality, maybe in which we're embedded, with the string is not fundamental, but a plane is what's fundamental.

“- Yes, and that's one of the developments”

in string theory itself. So when we talk about these membranes, the piece of bread, or the card in the deck. - The theory up by a dimension. - And string theory takes you there.

It's not something again that you put in by hand. - He goes wherever his equations want to tell you. - That's the size. - Well, yes. I need to say, this is a purely mathematical

- That's what it's called. - Totally, yes, but the beauty of it is, you don't put things in from the outside. You study the equations and it takes decades sometimes, but you extract what the equations

are trying to tell you. - So before you go to queries, what is the current state of string theory? - Current state is, yeah, you know, it's funny.

I asked this question in a program to three string theorists. World Science Festival program. I asked them, "Guys, grade, string theory." How, you know, string theory was a student, you know,

how would you grade it? And the grades went from B plus. I think that may have been a Nobel Laureate David Gross. I could be getting their grades wrong, to an A plus, which was Andy Stromminger,

who was a string theorist at Harvard. And if you look at its theoretical insight into black holes, the mathematical insights that it's given started whole fields of mathematics, if you have any interest in the nature of space and time

and what it might be made of, these are the kinds of insights that string theorists giving. So I say it's very healthy, but it has not made a prediction.

Allow us to determine whether it's correct well.

And that's almost a violation of one of the most important

tenets of a viable theory.

“Yes, and that's why maybe you shouldn't call it string theory.”

OK, so we can go. Yeah, maybe call it the string hypothesis. OK. Theory really should be considered. I'd say more humble.

Yeah. But the math makes it a theory. Well, theory, yeah, for a theory to be a bona fide theory, it's got a not only account for what you see, or even organized coherent way.

It's got to make predictions that you have verified. Right. You've got to be able to predict it. Then it's only one half of what's going on. And then it does.

Yeah, so we're using the word wrong. And I agree with people who are sticklers on that. Got it. But it's that because-- and I don't want to sound like a jackass.

But what you just explained, I got to say, like, I just hadn't had it easy. I'm serious. Yeah, right.

I said, how easy compared to what you're just talking about.

I agree. He wrote down his equations. And within a handful of years, you could test it. Right, because it's here. Right.

It's right. It's around us. It's everywhere. Like, you're talking about stuff that is-- I mean, how do you get to it?

Right. We've had problems unsolved problems that have lasted much longer than these 40 years in the history of science. OK. So it took a long time to understand heat and energy.

That's very funny, what you just said. It took us a very long time to understand heat. [LAUGHTER] No, we didn't know what it was. The fundamental basis of it.

That's hilarious. No, we didn't know. Is it a simple-- I flew it. Right.

The more it, they call it the color of the flame. Yeah, yeah. And you know where we did most-- Oh, look. Well, no, that's the air looking.

The air is a fluid. The air is a fluid, though. That's not a heat. But go ahead. One of the main centers of experiments for this?

Yeah. We're cannons. Because you fire cannons, the metal gets hot. Yeah. So as we got hotter, they weigh it to see if it had more heat.

If the heat wasn't thin. Right. If it was like-- Because that's the heat. Because that's the heat.

Yeah, so we went decades and decades with other-- It's just so maybe I shouldn't be so hard on string theory. Yeah, this is a pretty good place to have gotten. Let's wrap it up right here, fellas. [LAUGHTER]

Thank you, goodnight. [LAUGHTER] And one last thing, I want to hear it again, because it was so beautiful, all right? So beautiful.

Just tell me, speak to me, Brian. [LAUGHTER] Because it's sweetness to my ears.

“When I heard you say, I think it was you,”

that the virtual particles in the vacuum of space coming in and out of existence as predicted by quantum physics, they are quantum entangled with each other. And that quantum entanglement are wormholes. And those wormholes represent the literal fabric

that stitches together the universe itself. Yeah, we were definitely talking about this at some point. Now, where are we on that? Well, it's a beautiful idea. Really?

It really comes from Lenny Susskahn and Juan Maldesena and a whole army of string theorists who developed these ideas. He came here, gave a talk, whatever, evening, talks

Yeah, he is wonderful, both, very innovative guys.

“I mean, he's driven physics for decades.”

So he and Juan Maldesena realized that these quantum entangled particles, which Einstein really in a sense predicted in his EPR paper, Einstein Pedolsky and Rosen in 1935, may be connected to another Einsteinian idea, which he

came up with a two months distinct from that first paper,

and Einstein Rosen paper on wormholes. That is two particles that are far apart can have a subtle quantum link, and that quantum link may be nothing but a wormhole yielding a short cut through the fabric of space that, in some sense,

makes them very close to each other. And those wormholes themselves are what space time is comprised of. Yeah, so a substrate of space itself would be wormholes. Yes.

That's right. So Mark Vom Romsdok and British Columbia Canadian physicist realized that these wormholes may be the fiber stitching together the fabric of space itself, because he could show math thematically,

if you cut the quantum entanglement, the fabric of space polverizes it, falls apart, because you no longer have the wormholes connecting pieces of space together. That is wild. OK, I'm going to--

That's great. That's great. [MUSIC PLAYING] It's time for cosmic query. We should have some jingle or something

that was some animation and some animation would be good. Cosmic queries. Right. Questions asked by you, if you're a patreon member, knowing that our guest today is Brian Greene, the one and only.

So we have a starter question. Yes. From one of our own producers. Yeah. Tamsin, our producer.

Yeah. Our task master. Yeah. [LAUGHTER] Tamsin wants to know this, Brian, if space time had consciousness

and could have a favorite movie. [LAUGHTER] What do you think that movie would be?

“I think it would be a planet of the apes.”

Really? Oh, this. Oh, that's seen at the end. You know, the half sub-mergeist-- Yeah, it's a--

Yeah, you did. Yeah. No, no, no, no, no. You-- [LAUGHTER] Damn, no, no, no, no.

[LAUGHTER] Damn, no, no. That's it. [LAUGHTER] Wow.

Yeah. Because that played Lucy Goosey with space time. Yeah. To go into the future, it's another earth. And it was a different evolutionary path.

It was the first time that time travel really meant something

to me as a kid, like, oh, man, this is crazy. Yeah. Wow. That's a good one, man. Yeah, a planet of the original.

The original. Forget about the other, yeah, 75,000. That was so long the world's red. Exactly. Return to the apes.

Get some of it there, Brian of the planet of the apes. The planet of the apes, you know what I went back and saw that film. It's actually quite deep because the different species of apes had different roles. That's right. It's a cancer.

It's a cancer. Right. So the chimpanzees were the academic class, right? Because they're close, why not? We call it there.

Our closest cousins. And the baboons were like the police, right? Yeah. We're a gorilla. There's a real police.

And the orangutans are the elders. No, the orangutans were the diplomats. The diplomats. That's right. The politicians.

What's the caste system? Yeah, that's right. It's pretty wild.

So our first few questions have been previously asked by our patrons, supporters.

But you said I'm going to have to see what Brian says about it. Oh, right. So they were elevated. They were elevated. Okay.

Right. They were elevated. They wrote in with a question and you were like, let me give my supervisor. Okay. I want you to go.

“So this is what Brian Burke, he says, hey, Dr. Tyson Lordenice, Chuck, you should be able”

to nail this one. It's Brian from court to Brian Shut up. He says, can you help explain the information paradox with black holes? My understanding is that quantum mechanics and hooking radiation are at odds about this. And says information is forever, the other says information just appears when a black hole evaporates.

Are we any closer to understanding how this can be? Thanks. And please keep doing what you're doing. We need real science to carry on live long and process. Oh, nice.

No need preface that a little more here.

So I was delighted to learn that the evaporation of black holes, the Hawking Radiation, is the exact inventory of fundamental particles that went in, even though it's being conjured out of the gravitational field of the black hole itself, the energy density of the field. So I said, oh, so that's a total reckoning of ingredients.

But if I went in as a DNA molecule and I come out as the various fundamental particles, the information that I was DNA has gone. So no, there's no preservation of information there. And that's what Stephen Hawking said. So when Stephen Hawking did his initial calculations in the 1970s, he came up with this

idea that black holes could actually radiate through quantum processes. The production of particles just outside the edge of a black hole, one falls in and the other races away. And the question was, do the particles race away?

“Have the information content about everything that fell in or don't they?”

He said they don't. My calculation show it's a thermal bath of particles of a nello featureless bath of particle, no information inside of it.

We particle physicists said, come on, quantum mechanics doesn't allow information to be lost

or destroyed. So if you're saying that, you're saying quantum mechanics is wrong and we're not willing to go there. Yeah, quantum is so successful, right? Yes, you got to be ready for, you got to be somebody more to Stephen Hawking.

And this led Lenny Susskin again, and Gerard Atoff, to one Nobel Prize, and various other people to spend 25 years trying to answer this question. And we believe largely from string theory that we do understand that the information does in a very subtle way come out of the black hole, subtle quantum correlations between the particles that emerge from the black hole do carry all the information of say the DNA,

molecule that fell in. So you can recover all the information we believe. Now there are still mysteries that we're still figuring out, but just about everybody, including Hawking before he passed away, agrees that we believe the information does come out. Press the question, what's it with?

Press the question. John Presco. Yeah, great.

“But a postdoc, when I was a graduate student at the university, it's okay.”

Yeah. So we're still one of the best. So Pressco won the bet, but Kip Thorne was also part of this, and Kip Thorne was unwilling to complete. If he is on in our archives, check him out.

Yeah, absolutely. We interviewed him in his office in Pasadena. So Hawking conceded the bet that John Presco said the information does come out and he gave him an encyclopedia of baseball, a lot of information he provided him. As they waited for.

But he has too much information. No, you haven't mistaken. That's right. It made good on his bet. I don't know where Kip Thorne stands on this.

I don't know if he has conceded. Okay. Okay. What's the business about the information being stored in the event horizon? Have you?

Yes. So what do you call that? That's the holographic. Oh, a holographic idea. And that's part of the solution for why we believe the information is out.

That's going again. So it's going again. That's this guy is incredible. He's fallen into a black hole and we believe that they leave on the surface.

“In some sense, a copy, a residue of their information and that's how the king come back”

to him.

He never actually goes away.

He never went away. The end print was left on the event horizon. Yes. Very cool man. Super cool man.

Yes. So we have an explainer on whether or not we're living in a black hole. We could be property. Yeah, we could be. We could be.

Yeah. This is big enough. Yeah. Okay. Okay.

Okay. Let's go. Yeah. Right. Just says, what's up.

Dr. T. Rachel here from Austin, Texas. I've been thinking about the spinning universe hypothesis. Which suggests our cosmos might be rotating as a home. This idea has been proposed as a potential way to resolve the Hubble tension. But it got me wondering, if the universe isn't deep spinning, could the force we attribute

to dark energy, which is causing the accelerated expansion, actually be explained by a kind of cosmic, centrifugal force. So she's saying that we just want to really, really, really, really, we're in the whirling nervous. We're in a tea cup.

Yeah. It's hard to say how you'd make that work. When we see the evidence for dark energy, it seems to be so called isotropic. It's the same in every direction which you look. Whereas if the universe is spinning, there's an axis.

There's an angular momentum that picks out some directions as different from others. That's right. So it's hard to see how that works. There's no centrifugal force. Yes.

But if you look off the axis, we study the motion of distant galaxies. We'll look across the entire region.

I think to rule that possibility out.

But who knows? Right. A paper. Oh, love. Yeah.

That was good. All right. What a great question. It's a regular question now.

“When we pull out one that was there, and I forgot who asked it, and it was about whether”

we'd have a quark catastrophe. So we had a Patreon member right in. The questioner knew that if you have two quarks in some kind of nucleon, then you try to pull them apart. There's a point where that snaps.

But you've invested so much energy in it that two new quarks show up in that instant. Now you have two pairs of quarks, right? We go with that. Yeah.

In a black hole, or maybe in the big rip, either.

Let's look at your descending to the singularity. The two quark particle falls. Tidal forces get greater and greater. And then it splits the two quarks. So now we come two pairs of quarks as they fall in.

Then it becomes four pairs, and then eight pairs. So just be this unlimited increase in the number of quarks as it descends to the singularity. Why doesn't that happen? Well, you do feel tidal forces as you get ever closer to the center for sure, but I'm not a quark.

And it's a finite time scale between when you cross the event horizon and you hit the singularity.

“And I can well imagine that particle pairs are created in the last moments of this.”

But where they're all of the energy gets transformed in this way, that seems unlikely. It has to happen after I rethought about it, because it's pulling that energy out of the black hole. So it would evaporate the whole thing. Oh, if they're thinking that an infinite energy transfer, then yeah, absolutely.

Everything is finite. Time scale is finite.

Energy is, and so yeah, exotic processes can certainly happen when they gravitation

forces that powerful. Right. Now, of course, when you get to the singularity, we have no idea what actually happened. That's a pretty serious, haven't figured it out yet. We have nothing.

That's okay. But that's actually a real point. That's one of the goals that we've not yet achieved. And the grip would be the same thing. There's a point where the...

Yeah, that's true, too. Yeah, the expansion. If it was sufficiently high, it would get on the scale of nucleons and split apart the quark or a pair. And making another pair.

Yep. Yep. I mean, there are many other processes that can happen in the world. So I wouldn't just focus on this. There are all sorts of ways that energy can transfer from the big grip or the gravitational

energy of a black hole into a particle production into various kinds of processes. Yeah, creates a whole universe of quarks. I don't know. I mean, you'd have to sort of calculate the rate at which those processes happen. I would do those things.

Yeah, the entire dark energy universe inside you, but we're still inside the black hole. No, no. Now we're just looking at the big grip. Yeah. What's happening is using up the energy of...

But then, of course, if that were the case, it would no longer undergo the accelerated expansion. Yeah, yeah. Yeah. That's right. Okay.

All right. This is Michael De La Morena, who says, "It's time to dimension or a field. It seems more like a field because it can be affected by gravity." That was another one that I punted to Brian. "It's time to dimension or a field."

Well, I'd say the deep lesson of Einstein was that space and time can be affected by their environment. And they, in turn, create the very environment that then backreacts on their own shape and structure. And so we usually think about time as a coordinate, a label telling us when things happen,

just like coordinates and space tell us where things happen and the unexpected thing is that label, the amount of time between two different locations can be influenced by the force of gravity. Right. But that doesn't require that it be a field.

Yes. It doesn't require it be a field. To be influenced by a force. But I understand the intuition because we used to think that the labels, the locations of where and when things happen in Newtonian perspective, they're just inert, they just sit there,

they don't do anything. Einstein elevated them to be dynamical qualities of the world. And that's the deep lesson. Very cool. All right.

Great question, Michael. This is Cody Rosenberg, who says, "Hello, doctors and Chuck. I'm Cody Rosenberg from Eugene, Oregon. Please know that y'all are goded for us, armchair, astrophysics, physicists, enthusiasts."

Very nice.

“Anyway, do you guys think that life is inevitable?”

Do you think it would be weird for a universe to exist that can't be experienced or observed?

It says a very John Wheeler, like way of looking at the world, Wheeler loved to say that

“we are the way that the universe becomes cognizant of itself.”

So, it's a mixture of you, with an eyeball. Yeah, yeah. The you, a serifed you, and on one of the upwards of the you, there's an eyeball looking at the other one. We love you.

Very nice universe. Looking at itself. So, narcissistic or beautiful depending on your perspectives, that we're here so the universe can think about itself. I don't know of any law that makes life inevitable, it seems it was a lot of happenstance

between the big bang and today, but we don't understand a lot about the world. Maybe one day we'll find there's this law, this inevitability of the existence of galaxies and stars and planets and people, at least on one such planet, I don't know of any such law. Tell me, I see both this.

But there's some thinking that, and this is wishful thinking, not because someone has researched this, that you go to a different planet, you can take a geologist there. It'll be comfortable there, because they'll know what a rock of, you know, doesn't give you a rock. Because they see the rock crap everywhere.

Yeah, that's right. So the rocks and the minerals, there might be some more exotic ones, but they have a sense of how what elements do when they're heated for a certain amount of time, under pressure. Right. And that repeats depending on the planet.

So we can, so there's general rules of geology that apply to all planets. So let's go to biology. Yeah, could the DNA molecule be a natural consequence of complex chemistry operating on planetary surfaces? It could it be as natural on a planet as rock to the geologist.

“And that's what I was about to ask, both of you can chime in on this, how cheap is life?”

So forget, if it's inevitable, how cheap is life? I don't know what that means. Well, it's said it formed relatively quickly on a planet, or so it didn't take an enormous amount of time. That's a year as you say, well, that was some hard stuff.

Yeah. Yeah.

It formed in just, in fact, how one do you think it puts a billion, I tell you?

Okay. So we used to say. Okay. Well, you said no. Okay.

We used to say that because you'd start the clock at when Earth formed, right, four and a half billion years. Yeah. And then the early sense of life for like 3.8, 3.9, so you say 600 million years, we used to say.

And then we said, no, no, that's unfair. That's unfair. But, or form, there was periods of heavy bombardment, where the surface of the earth could not have sustained complex chemistry, of course, because the energy is too high, breaks a part of it.

Yeah. Let the earth cool for goodness sake. Yeah.

So the cooling, you let it cool, so add about four billion years, it's half a billion

years. And four billion is now you start the clock, and you have life 200 million years like, wow, that's really great. Yeah. Right.

In the grand scheme. Yeah. So that's what I'm saying. Why percent of the total time earth has been around. So, again, however, I think that's likely the way to talk about it.

But there are so many detailed physical chemical processes that maybe they just so happen to come together in this one planet of the trillion that are out there. So when we understand it better, that cheapness, we may explain it by a coincidence of a whole lot of factors that just happened to a line on our planet.

“I don't think that's how it's going to turn out, but it's a possibility.”

It's a possibility. Yeah. Well, except there are amino acids on media rights, we just found them already. Right. Yeah.

And interesting question, though, is the way that proteins are coded by amino acids is uniform across all life. It's the same code, three base pairs on the genetic code, give rise to a particular amino acid. That is the code that works for you, me and all life.

On another planet, if there is other form of life, the deep question will be, is it the same code? Right. Or is it different? So, doesn't need DNA at all.

Right. Right. And so, if it's different, that would be wonderful. That would suggest that life in a whole variety of different forms can exist. It would not be in a fully explored, all the ways of being alive.

Yeah. Yeah. Well, all right. Well, great question. Way to go, Cody.

All right. This is Aaron Bailey, who says, hey, start talk. I am Aaron from Florida. I am. And we're sorry.

Which one? I am. Florida, try it. Yeah.

So, Aaron says, long time viewer, first time subscriber, thank you, or may appreciate

that. According to Einstein's equations, is time travel still possible if you are traveling to a black hole and why can't we use gravitational detectors to measure the properties of dark matter? So, in the first question, yeah, I mean, Einstein's special and

general activity, both embrace a certain kind of time travel.

If you go hang out near a black hole, time for you elapses more slowly compared to someone

“as far away, famously portrayed in interstellar.”

So, if you go to the edge of a black hole and you hang out and then you come back, everyone that you meet is going to be much older. Their clock was going much faster than your clock. And that is. Some people say, well, that's not time travel.

That is time travel. Certainly. I've traveled into their future, which would have been your future if you had there. Exactly. And you would have left up in the ship.

The black dude. He came back like, oh, man. 23 years. Six years. Yeah.

I don't know if you know how serious I am now. You know how much social security. I don't get it. You go down there. You're telling me you come right back.

You're asking me to tell you where's the book is. You're asking me to get it. I don't get it, ma'am, ma'am, ma'am, come here. All right.

What was the second half to that book?

What was the second half?

“The second half, he says, why can't we use gravitational detectors to measure the properties”

of dark matter? Well, we do. The way we know dark matter exists is by the gravitational influence that it has on its environment. What we're unable to do is identify what the dark matter is made of.

And so we have these detectors all over the planet trying to capture little particles of dark matter. And that's the right explanation. We haven't been able to find any of that. We don't do that.

We're going to do that. Okay. You know, they're pulsars. Yes. Rapidly rotating neutron stars.

They do very precisely. Extremely precise. Right. And they're across the galaxy. They're not all that many of them.

Right. But there's enough to map out the galaxy. So if you precisely know and measure the pulses of these pulsars, you can track a gravitational wave moving across the galaxy. Yes.

And we're kind of like booze in the ocean. Good. The knowledge. Yeah. You don't even need LIGO for that.

Yeah. Yeah. Just need high-consensitive high precision time. Yeah. For gravitational waves of a certain wavelength, this is a beautiful way of detecting their

influence. Cool, man. Yeah. All right. Let's move on to Alex Frias, who says, "Hey, Dr. Tyson Lordenis, Alex here from Mexico."

Oh, I should say, "Alex." No, Alex Hamdler. Alex Hamdler from Mexico. Why? Why?

Is that racist that you assume? I can be racist. I'm black. I don't know if you realize. Okay.

The world in Vinnie Racism for me. Okay. Okay. Here we go for me. He said, "What did I tell you?"

It was, I was given a public talk and I thought I'd say something funny. I was talking about the dinosaurs and they went extinct by an asteroid that hit the Eucutam Peninsula. Eucutam Peninsula of Mexico. And I said, "But that's not what the dinosaurs called it."

Okay. I thought it'd be funny. Right. I think everybody. And so one of the front row said, "They called it, "Make it."

That's funny too. That's funny too. That's funny too. That's funny. That's funny too.

That's funny too. Yeah. Okay. And then you had Trumposaurus, who was just like, "Give 'em out." Anyway.

I've always been intrigued and confused by the idea of super symmetry.

Oh, nice. If the standard model of particle physics is one of the most successful theories we have. What is telling us? That it needs doubling up.

“What would super symmetry fix in our understanding of the universe?”

And what problems might it create? Thank you both and greetings from your neighbors in the beautiful upper west side. Oh, nice. Oh, nice. Look at that.

Way to go, Alex. Run right to the street. Up and down. Right. So let me sharpen that even further.

So the standard model is quite an organizational map of our particles and particles in the lake. In its current state, now that we've got the Higgs- The Higgs, is it missing anything? Is it a closed box right now?

And if we do anything to it, does it simply make it more powerful? Or do we know we need things to explain other things that we don't yet understand? Good. So the main motivation for super symmetry is to address exactly the way you frame the question, which is when we study this Higgs particle, this newest addition that we found in July

4th, 2012, at least that's where the announcement was. When you look at the mathematics, it says that the mass of the Higgs particle should be much much bigger than the mass that we find. And when we try to keep the mass at the value measured,

We have to tune and tune and tune.

“If super symmetry were true, the terms that would push the Higgs mass up,”

they cancel out from those pairings. That's why we need the pairings. That's why we need to doubling. And if you can cancel out the new contributions, you can rest easy. The Higgs mass will stay at a small value.

So how many more particles come along? It doubles it. It really does for every known particle. There is a partner's electrons. Super symmetric.

Super symmetric. Yeah, so the electron has the electron, corks, corks. Nutrinos, snootrinos. No. No.

Yes. I don't name them. No, no. Yeah. Why?

Because somebody when they found that they're like, no, neutrinos. And so the big hope, if you would have spoken to me on as a graduate student in the 1980s, the big hope and the reason we believe that string theory might be five years away. It was.

We expected super symmetry, which is the super in super string theory. We thought it would be found. Those particles would be found at the Large Hadron Collider. And they were not found. Wow.

And so this did not never be found.

Well, that's probably true. Because the collider has a limited energy reach. Nothing in our theories tells us how massive the partner particles would be. If there's sufficiently massive, they'll be beyond the reach of the Large Hadron Collider. So there's a natural explanation for why.

We didn't find the particles, but we were certain that we would. He wants another collider. Yeah. There you go. So you don't need one of them.

Look at that. Well, that's fascinating though. OK.

“And does the Higgs have the, do we have a name for the other particle?”

Higgsino. Higgsino? Yeah. I prefer squigs. Unfortunately.

I'm going to go with squarks and I'm going to go with squigs. The photon, what's the, similar to the photon? Photenow. Really? Really?

OK. And the W and Z bosons. Those are harder. Z nose or we nose. We nose.

We nose. We nose. They get a little bit. Yeah. But we're talking about doesn't have gravity in it when you're just talking about the standard model.

Oh, yeah. Yeah. But if you include gravity. Right. Then there is a version.

It's called supergravity. And it comes out of string theory as well. And it's the gravity now. Right. All right.

All right. From the gravity on. Yeah. OK. All right.

Well, way to go there, Alex. We're still looking for him. Yeah. You still looking for him. There's no evidence.

It's just a matter of a lack of detectors. Could you build enough detectors? Well, we could get all this capture. All this stuff. And not so much detectors.

It's a matter of the energy. So how big the detector. How big the collider is. Right. And that's, you know, colliders are expensive.

And the bigger they are, the more money they cost. And we had a big one going in and out. You know, and I'm inside of the pond. Mm-hmm. The superconducting supercollider in Texas.

And I funded in the 1980s under Reagan. Right. And Doug the whole got already. Walks a hatchy Texas. It would be three times as powerful.

I think. Yeah. And 50 TV and we have 14 TV. Yeah. Yeah.

So three times the power of the, of the one that was built in Switzerland. And then early 90s, they zeroed the budget. And they saw all those cost over runs. And it's quite a thing. But, but.

Oh, some kind of defense thing. We no longer were fighting for a lot. Yeah. Europe. That's all about.

Yes. Yes. Yes. Yes. Peace breaks out in all of a sudden.

It's like we don't need to necessarily need this. What do we need physicists for? And their little toys.

You never heard of cost over runs.

And any other particle accelerator for the whole 20th century. Right. Interesting. Yeah. This is Blake who says, hey, it's Blake greetings from warm.

Sunny. Columbia, South Carolina. Oh, wait a minute. Wait a minute. They're Blake.

He says there are quite a few theoretical particles that have been discussed. On this show, the gravitation, the tacky on strings, etc. But we don't seem close to actually finding any of them. Are there any experiments proposed that might help us capture and learn about these loses particles if they exist?

And slightly more an engineering question if we did find them. How might we use them for the benefit of humanity? Do they have a use if we find them? I mean, well, if dark matters actually found that it is a particle look. So deep in our confidence or understanding, can I imagine applying dark matter particles

to build something? The whole point is they're incredibly elusive. They only interact.

“How do we even capture them if they don't interact with anything?”

Well, they don't interact with themselves. They interact with themselves.

And these dark matter particles through indirect quantum processes do interact with ordinary

matter.

“And that's how these detectives are so ready.”

Oh, yeah, well, yes. Well, that's the dark energy. Yeah. But it's the same basic idea. And so, yes, you can detect these things, but that's different from gathering them together

and engineering with them. So I don't see any direct benefit that comes out. But again, it's the same argument we made before. The deeper you understand. That's the one.

And there's someone who figures out where that goes. That's where it just plays up. Yeah. Okay, got you. All right.

This is Luke Senior who says, "Mess regards from Juliet."

He says, "Dr. Leakle of Port of PhD Translation Scholar and Sonologist." He says, "Could it be the entanglement phenomenon?" It's simply a matter of absence of the time dimension at the scale of the particles. And that we see two particles interacting instantaneously at a distance in some, you know, his word, magical way.

In their own three dimensions, only universe, they're just unaware that a change of state has occurred. That for them, there's no before entanglement slash after entanglement. Thank you very much. It's a very well thought out question. Does it make sense?

It does.

“And I think we can interpret it more or less along this wormhole idea that we were describing before.”

The wormhole notion, again, this is still very much at the forefront. We're still working out the details. But if it is the case that two distant particles are connected by a wormhole. If they're entangled, quantum mechanically, then it would be as if they're right next to each other. They don't know the same thing.

So then they don't know that they're far apart. And so that's the variation on the same thing. I don't think you can say they live in a world without time. Right. Because the conundrum is to us beings that do have time.

You do something here and instantaneously, according to us, affect something over there. And that would still be a puzzle no matter what. And one explanation would be, well, they're actually closer together than you think by looking at them because they have the secret shortcut connection, which could be the wormhole. So I think for so many years, people were imagining wormholes as some kind of a ride on in a water park.

Exactly. You know, even in the movie, contact. The Jodie Foster is going to screw it right. And so, but no, would you just step through here? No, you step through here.

“I think it depends on the nature of the wormhole.”

But yeah, there can be birds and birds effectively stepping from one place to another. Right. And they're not attracted to it right though. They had a portal where it looked like a doorway threshold. Sitting on the edge of forever.

And that's a wormhole. You step through it and you're already there. Yeah. There's no ride. There's no, you just step through it.

And that's another one where they're going to save someone's life. Yeah. And they realize what they're going to change the future. Yes. Yes.

I was talking with Bill. And he said that was his favorite episode. Really. Yes. My favorite watching is a viewer.

Yes. Because it dealt with time travel in a very emotional way. Emotional, emotional and unorthodox way. Yeah. And cause all of these exactly addressed.

All right. Zachary Aces, although Dr. Tyson Lord and I is Dr. Green, is it possible that through the many worlds interpretation, quantum immortality can become macroscopic. If every single possible state of every single particle in existence is equally real,

I feel like the superposition of a single particle in quantum immortality theory can be expanded to incorporate the superposition of every single particle in existence. Yeah. And look, you know, another way of saying it is, we said before that the many worlds allows a world in which anything compatible with physics is realized,

us living to a hundred, two hundred, five hundred, a thousand. I don't know that there's a law of physics that can happen. Now there is a law of Jesus on board. You can't imagine living a thousand years. Oh, kill me, just think about it.

I want to die. So wait, here's something that we did not raise. Which was, if there's another identical me, is it me? That's the deep question. That's not what the consciousness question.

And I think the answer that is yes.

No, is that the answer is no?

Why? Because we've already kind of done that experiment. No, I'm saying that person has literally your memories, literally yourself of sense of self until something measurement has that causes you to be different from that.

Yeah. So it's truly you. That's why. I mean, if I spoke to that version of you,

That's me. It's me, damn it. That's funny. Yeah. I don't know what to say.

I've never heard you say that before.

So that means we are living forever. They're the reincarnation from them. They're all over this. That's right. Why?

Or at least extraordinarily long.

“Maybe there is some physical law about maybe the proton decay”

or the proton decay. Yeah. Yeah. Well, we tend to have whatever. Yeah.

Yeah. Wow. All right. This is Marcus Ruzon. And Marcus Ruzon says, hello, Neil and Brian.

Love the show. I've been wondering something about time and light. If nothing can travel faster than light, and the speed of light is a universal constant. Could it be that time itself is actually an emergent property

of light? Is it possible that what we perceive as time is actually just a consequence of us traveling through space time. And a finite speed below the speed of light. Is that not confirmed by the fact that from the point of view of a

photon, there is no time thanks and keep looking up from Singapore. Yeah. Okay. And it is some poetic sense. I agree with what the question is.

Yeah. Yeah. Yeah. They're saying that if a photon had consciousness. Right.

From its perspective. It would not know. It would not know that time is less than time.

“Now, I think it's really important to recognize that you're extrapolating.”

Einstein's result to a particle for whom the equations don't literally apply in the way that we're using them. Correct. So if you apply Einstein's it is to any massive body, you find that they can't travel at the speed of light.

And therefore they will always have this conception of time.

Exactly. But if you want to push it to the absolute limit, which I call poetry, not quite mathematics, then yes. Right. Because the key is the photon has no mass.

Yes. That's the key. Yes. That's it. So once you have mass, you can't be a photon and you can't you'll never experience

with that photon. Precisely. All right. Okay. Well, there you go, Marcus.

But thanks for the, you know, I have nothing to add to that. Okay. No. All right. This is Patrick Dietz.

And Patrick says hello Dr. Tyson, Dr. Greenlord, nice Pat Dietz from Revena, Michigan. Could the reason we cannot see dark matter also account for the expansion of the universe due to dark matter moves faster than light. Let me read that again. Good.

The reason we cannot see dark matter. Also account for the expansion of the universe due to dark matter moving faster than light. Okay. That's a tough one to have parts. It's really rough, but yeah.

I see what he's saying.

“How can you see the thing that's faster than the thing that allows you to see the thing?”

Right.

I get this sort of collection of words, but the problem is.

Okay. By the way, people to sexual words. This is why I love scientists. Because they know how to call you a dumbass. [laughter]

Well, never saying those words. The important point is that for a particle to be a particle of dark matter, it has to have mass. Right. Once it has mass, it can't travel faster than light. So the ideas don't mel together in a consistent way.

There you go. All right. I like the question. Just for the fun of it. All right.

Patrick, this is Mr. Zoot. And Mr. Zoot says, "Dear Star Talkers, Jeffrey here. Penance, Jeffrey, Chuck." [laughter] Screw you, Mr. Zoot.

[laughter] He says, "I understand electron orbitals are really probability clouds, but still exist in discrete energy levels around the nucleus. What then happens during ionization? Do they stay as a probability cloud?

Just untethered from their anchors, so to speak? Do they still have discrete energy levels? Hey, what gives? And thanks. So if that is a great question.

It's a nice thinking. And so it certainly does stay as a probability cloud or probability wave if an electron is going to die. And I say it from hydrogen. But if that electron is living in a universe that is not a box,

that's infinitely big, then we don't believe it's energy level. Will be quantized. Do you think it could be continuing? Yes, so if you have a particle in a box. If you have a particle in a box, then the energy levels are quantized,

If you're solving the wave equation. You're saving the wave equation of the box. You're expanding, what's it called? The harmonic. The harmonic.

Yes. And the harmonics have to die. They have to fit inside the box, but if there's no box, then they could have any wavelength at all. The energy of a free electron is not quantized.

Correct. I did not know that.

I've never heard that before.

It's obvious that it could only be that way. That's why. That's why. That's absolutely why. Very cool, man.

Wow. Great question.

“Just to highlight, because he said something important here.”

Yeah. So we'll call it a box. But let's look at a tube. Let's look at a organ tube. Okay.

Like a pipe organ. Right. You can ask, what kind of wave can you set up inside that tube? And it can only hold a wave where the complete wave is there. Right.

You can't hold like a half wave. Right. So it sets what the wavelength is. The frequency of the sound. That's the wavelength.

You get that from the wavelength. And each tube. So different tubes have different frequencies. That resonate inside of those tubes. Right.

And so I think of atoms, I think of you got the nucleus with the protons, sets up a box. And so you then you do the math. And you get a set of wavelengths. I'll call them that. That fit inside this box.

And if you need for every atom.

“And that's what gives you the spectre of each atom.”

That's what each atom has a unique spectrum. Right. Yeah. It's really cool. That is X.

Wow. I learned stuff on this show. So great. So did I.

I just never thought about three electrons.

Yeah. Yeah. Okay. This is Brian Nado, who says, hey, Dr. Tyson, Dr. Green, Lord Nice, Brian from upstate New York here. With the discovery and verification of the Graviton, assist and all in reconciling general relativity and quantum.

I like that. Yeah. Isn't it just assumed that there's a Graviton? And that assumption needs to be verified. Hopefully.

And what's the energy of a Graviton relative to the waves that we just detected? Well, the energy that the mass of a Graviton, we believe is zero because gravity also travels at the speed of light. So it's much like a photo on that picture. Yeah. Okay.

And yes, if we could ever really detect a Graviton to experiments with Graviton's scatter Gravitons off of each other.

“Then yes, we would learn an enormous amount about general relativity and quantum mechanics.”

Yeah. We'll have you version. Well, our quantum expression of gravity. That's right. In fact, the very existence of a Graviton would be the first evidence that gravity is quantized.

Yeah. And so we're assuming that there is a Graviton but verifying it would be huge stuff.

Who was the first to presume that?

The idea of the Graviton? I don't historically know. So the Graviton was the gravitational wave. Yeah. Well, so we have a wave.

We have a wave. It was a reluctant Gravitational wave person. He was really uncertain in 1916 and 1918 about whether they were real. Okay. Amazing.

Yeah. Yeah. So I'm just saying the quantum assumption is that we have a wave. You also have a particle. Yeah.

And like the photon is a wave and a particle. Yeah. Okay. Wow. Okay.

That's super cool. That's a good question. Who first introduced the very idea of a Graviton? I don't know the answer. It feels kind of natural if you're going to.

I'm going to look that one out. Quantum. Yeah. Quantum quantifying. Yeah.

All right. This is Tash Shaw and Tash says. Dear Dr. Tyson, Dr. Green Lord nice. I'm Tash from Orange Australia. I'm a long time listener so my boyfriend bought me a subscription to Patreon for Christmas.

No, nice. Very nice. What a nice boyfriend. Very nice gift. Yeah.

That's a smart man. I have read that other dimensions could potentially be detected through Gravitational and other anomalies. Yeah. I was wondering how we would be able to distinguish these from any effects of dark matter.

So, would there be domestic differentiation? Yeah. In fact, a proposal that was made a while ago is that at a collider, like the Large Hadron Collider, when you slam protons together, you can calculate and measure how much energy you have before the collision.

You can measure how much energy you have after the collision. And if we have less energy after the collision, that energy must have gone somewhere. And the possibility is the energy went into the other dimensions. Oh! And so this was missing energy signature of extra dimensions that we were again hoping we would see.

And not as what occurred in the first Dintrino experiment.

That's right.

“So it could be some other particle mysterious particle carrying away.”

But there's the first Dintrino experiment and there was an imbalance. Yeah. There was an imbalance. There was like, you start with this much energy and they have less. And you account it for all the particles.

Right. So we were like, well, maybe there's another particle. What's up with that? And they said, if there is a particle, it has to be neutral and it has to be very low mass. And the guy who proposed it was Italian.

So little neutral one, neutrino. Oh! Like Bambino, little baby. Bambino, neutrino, neutrino. What you got?

Jack. Let's go to Cosmic Moss. He says, hello, everyone. Love the show and every star you've had on it. You guys are great.

I loved where you teach. Please keep the education up. Dr. Tyson, Dr. Green, could theoretically or frequency be matched at two points in space by a micro particle. Uninhibited by resistance. Only to be met by its astrophysical counter-part.

Well, I think you should take this. I don't know what I understand the question. Kind of like matter anti-matter, but the particle is already in existence. And then it's a counterpart that impedes, I guess, the entanglement.

It's kind of like, read the first sentence again.

Alright, he goes, could theoretically or frequency. Alright. So that's the, I guess, his version of the string. Be matched at two points in space by a micro particle. So that's the entanglement, maybe.

Uninhibited by a resistance. Only to be met by its astrophysical counter-part. The only counterpart particles are entanglement. That's it. That's what I'm saying.

And there's not much anti-matter in the universe. Right. In fact, well, other than the centers of stars, we probably make all the anti-matter there is in the universe on earth. Would you say?

No, I haven't done the calculation, but I can imagine that. Let me just think about that. It was a plenty of anti-matter made in the center of the universe. Most anti-matter in the universe would get annihilated, fundamentally in the centers of the sun.

The cool part was in one of the Dan Brown stories. The Catholic Church had a violent anti-matter. Okay. That's so funny. Dominic's spirit up, he's gone.

Physics jokes people. No. So yeah, I don't quite clear. If it medits that's the counterpart with the annihilate, no matter what else is going on.

Yeah. All right. So here we go. Kenny Watts says this. Hey, Dr. Tyson, Dr. Greens,

Lord nice Kenny from Dothan, Alabama. Is the reason why we can't reach the absolute zero degrees in temperature because of the CMB? Is it due to the act of time using energy to move forward, creating heat?

And if we were to reach absolute zero degrees, would spacetime move forward in that region? Yeah. Yeah. That's the constant right.

So yeah. So my understanding of absolute zero is that, you know, all particle motion stops, except it doesn't because you have quantum fluctuations, even at absolute zero.

That's the key point right there.

Okay. That's the real barrier. Okay.

“So why isn't the cosmic microwave background a barrier?”

Well, if you didn't shield yourself from 2.7 degree photons, they would influence, but presumably if you're able to shield your environment. Yeah, but this is something would have to be temporary because the heat transfers.

Yeah. Sure. But an experiment takes place over a period of time. So as long as your time scales. That's right.

That's what how thermos work. Yeah. The time we do, which is this. So I think it's really the uncertainty principle is a true barrier against truly having particles at a definite location,

not moving. That would mean position and speed. We're both nailed down at the same time. At the same time, which is not happening right now. We're not going to do that.

Not happening. Wow. So the wave function would cease to exist if you were ever to get to the place where you could get the particle to stay exactly frozen.

Like still and definable in one point. Okay. So what is the temperature of that state of matter? Well, it depends on the details. You can calculate the quantum fluctuations of a field.

And if you tell me how it interacts and it's mass, you can calculate its quantum fluctuations.

“And indeed that's how you make predictions about the Casimir effect.”

Oh. Where you have, you know, two metal plates and there's empty space between them. And yet those plates can pull together because the fluctuations of the field inside are a little bit less

than the fluctuations outside. And that imbalance, you can actually calculate it. And you can determine how the plates come together. That is so freaky man. It's all freaky.

That is so freaky. I love it.

Oh, my goodness. And then they attract. Yeah. Yeah. Right.

And freaky dude. [laughter]

So we should do this every week.

What do you think? [laughter] No, Brian. You have a life. Thank you, Brian.

Not pleasure. This is great.

“You're working on a quantum physics book.”

Yep.

This is the decade, the Centennial Decade of the Discovery of Quantum Physics.

Exactly. We can't have too much quantum physics out there. Yeah. And this is for the general public. Yeah.

So we're finishing it up now in 2027. Should we get it out in this decade? Yeah. That's the key thing. Yeah.

All right.

“And this year, we're recording this in 2026.”

This is the Centennial of Edmund Hubble discovering that the Milky Way

is not the only galaxy in the universe. Wow. He discovers that in drama it is not just a fuzzy spiral sitting within our stars. There's a whole other island universe out there. That's, I love it.

That was a hundred years ago. So this has been a special edition because it's an extended conversation with my friend and colleague Brian Green right up the street at Columbia University. And Delight, thanks for spending the afternoon to my own. My pleasure.

It was a great fun. All right. And Chuck. Always a pleasure. Baby.

Yes. And catching you on YouTube. Well, you just smart enough. That's right. On the start talk, YouTube channel.

“Were you just smart enough for this conversation?”

Today I was the dumbass and happy to be so. All right. Until next time, you'll be the gravitation. Keep looking up.