Theoretical Physicist Brian Greene Thinks You Might Be a HologramBy Geek's Guide to the GalaxyEmail Author May 16, 2012
www.wired.com/underwire/2012/05/geeks-guide-brian-greene/Characters on Star Trek suffer frequent misadventures on the holodeck, a room that creates advanced holograms indistinguishable from reality. But now theoretical physicists such as Brian Greene, host of the recent PBS special The Fabric of the Cosmos, are starting to wonder if every object in the universe isn’t some sort of hologram.
“A hologram is a thin 2-D piece of plastic which, when illuminated correctly, yields a realistic three-dimensional image,” says Greene in this week’s episode of the Geek’s Guide to the Galaxy podcast. “The idea is, we may be that three-dimensional image of this more fundamental information on the 2-D surface that surrounds us.”
This notion, known as the holographic principle, came out of the study of black holes. Scientist Stephen Hawking believes information that enters a black hole is lost forever, but this seems to violate fundamental laws of physics, which led researchers such as Leonard Susskind and Gerard ‘t Hooft to consider alternatives.
“Over the course of many years,” says Greene, “they developed an idea that when an object falls into a black hole, yes indeed, it falls in, but a copy of all of its information content gets in some sense ‘smeared out’ on the surface of the black hole, on the horizon of the black hole. Smeared out in some sense like a series of 0′s and 1′s, the way information is stored in a typical computer.”
And if three-dimensional objects inside a black hole can be represented by two-dimensional data spread across its surface, the same might be true of our universe as a whole.
“Let me just point out, this is a hard idea even for physicists who work on it every day to fully grasp,” says Greene. “We’re still trying to really dot the i’s and cross the t’s and understand in detail what this would mean.”
Read our complete interview with Greene below, in which he discusses the physics behind some of science fiction’s most cherished tropes, including parallel worlds, black holes and time travel. Or listen to the interview in Episode 60 of the Geek’s Guide to the Galaxy podcast (downloadable above), which also features a discussion between hosts John Joseph Adams and David Barr Kirtley about parallel worlds in fantasy and science fiction, including a sneak peek at Adams’ new anthology, Other Worlds Than These.
Wired: You recently hosted a PBS special called The Fabric of the Cosmos. How did that program come about, and why should people go check it out?
Brian Greene: Well, it’s based on a book that I wrote with the same title, The Fabric of the Cosmos. It’s a show that explores some of the strangest features of modern science, but ideas that are well-grounded in mathematical research and observational data. So there’s one program that asks the question: What is space? The stuff that’s all around us. Another asks: What is time? This strange feature of our lives that’s so familiar yet so hard for science to pin down. And then there’s a program on quantum mechanics that explores the micro world, and focuses on a feature known as “entanglement,” where distant objects can somehow communicate with each other even though nothing travels between them. And finally there’s a program on the most far-out of all the subjects, the possibility that our universe is not the only universe, that we might be part of a multiverse.
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Wired: One of my favorite tropes in fantasy and science fiction is the idea of parallel worlds, but in science fiction and fantasy settings, typically what happens is somebody from the real world travels to a parallel world. So assuming that the multiverse is actually real, would it ever be possible to travel to a parallel world?
Greene: It’s pretty tough to imagine how that would happen. So you may know I have a recent book called The Hidden Reality, where I go through nine different variations on the theme of parallel universes. Because there isn’t just one flavor of parallel universe — there’s a version that comes out of quantum mechanics, there’s a version that comes out of cosmology, a version that comes out of string theory, and so forth. But one thing that they do share is it’s pretty tough, if not impossible, to go from one universe to another in any of these versions — in any conventional notion of what it would mean to travel from one universe to another.
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And it turns out that the most straightforward reading of the math of quantum mechanics — as realized by a guy named Hugh Everett all the way back in 1957 — the most straightforward reading is that the other potential outcomes actually do happen, they just happen in their own separate universe, which would mean that the experimenter, say me, would measure the particle and find it in one location in this universe and think that’s the only outcome, but there’d be another copy of me in a parallel world finding the particle at a different location, and another version of me still in yet another parallel universe that would find the third possible outcome.
So there’d be (another) of me, if there are three possible outcomes in these three parallel universes, so you could say that I “traveled,” in some sense, to all of them, because there would be a version of me in each of those universes. But the traditional notion of being able to jump from one universe to another, in the way that we see in movies or sometimes read about in books, it’s hard to see how that would have any meaning in this version of parallel universes, and a similar kind of discussion would apply to most of the others as well.
Wired: I listened to a lecture where you talked about how if you were to fly deep enough into outer space, you might in effect end up in a parallel universe?
Greene: Yeah, you’re absolutely right. So another version of parallel universes comes from far more simple considerations than quantum physics. If space goes on infinitely far, then there’s another flavor of parallel universe theory that emerges. Now, we don’t know that space goes on infinitely far, but it’s certainly a viable possibility that scientists today still seriously consider. And the version of parallel universes that comes out of that is pretty straightforward to grasp. You see, when we look out into space today, even with the most powerful telescope, there’s just so far we can see, because it takes light a certain amount of time to travel through space and reach us. So we only really have access to a chunk of space, if it goes on infinitely far, the chunk that could have sent out a light signal that would reach us by the time we look up today. So it’s roughly 30 to 40 billion light years, is the size of that chunk of space. It seems big, but if the universe is infinitely big, that’s just a small little patch — a little city, if you will, in a grand cosmic landscape that would go on much, much further than we have access to.
Now, the reason why that’s interesting is because in any finite region of space, matter can only arrange itself in finite many different configurations. It’s a fairly basic consequence of the laws of physics. And that means that if space goes on infinitely far out there, there have to be duplicates of us, and the argument is quite straight forward. Let me just give an analogy. Imagine I have a deck of cards, and started to shuffle the deck. Well, the cards will come out in different orders. You shuffle again, the cards will come out in a different order still, but since there are only finitely many cards in the deck, there are only finitely many distinct orders of those cards. It’s a big number, but it does mean that if you shuffle the cards enough times, sooner or later the order of the cards has to repeat.
Now, by the same reasoning, since matter could only arrange itself into finitely many different configurations in a given region of space … well, if you look region by region by region in an infinite cosmos, sooner or later the arrangements of the particles has to repeat. There aren’t enough different arrangements to go around, just like the shuffle of the deck of cards. Now, I’m just an arrangement of particles, as are you, as is anybody else, as is the earth, the sun, and so on. So if the particle arrangements here repeat someplace way out there, it means that you and I, the sun, the earth, they would be out there too. So that’s a sense in which there would be parallel realities way out there in the cosmos, if space goes on sufficiently far.
And now to your question. You’re right — if in principle you could travel sufficiently far, you might be able to reach those other domains, those other “parallel worlds.” But again physics comes in to pretty much thwart that possibility. First of all, we’re talking about gargantuan distances, distances that are so spectacularly large that we’ll never be able to traverse them — or at least, any conceivable technology that we know of would never be able to travel those distances. But even beyond that, we’ve learned that our universe isn’t static, it’s expanding, and in fact it’s expanding ever more quickly, and because of that there’s actually a barrier, a physical barrier, to how far we could ever traverse space, and that barrier would be too small for us to ever reach these other worlds. So again, the idea of being able to travel to a parallel world is likely one that can’t actually be realized.
(physically – from this reality to another – agree – the physics might be totally different – But in non-physical form – in the form of energy - spirit energy – essence - perhaps better described by a field of science not yet coined!
I Ponder what Sir Isaac Newton would have said about the recent Higgs-Boson discovery? Do you think he even had a clue about quantum particle theory – or any atomic or sub atomic theory. Didn’t mean neither were relevant in 1687)……
Wired: So going back to the Everett multiverse idea, how different could the laws of physics be in those parallel worlds? Are we talking about a different Periodic Table of Elements? Different fundamental constants? Different subatomic particles? What’s the degree of variation there?
Greene: Well, in the Everett many worlds interpretation of quantum mechanics, we aren’t actually imagining that the laws of physics or the properties of particles are varying. There are other versions of parallel universe theory, multiverse theory, that do however have this feature that you’re referring to, of different laws of physics and different particle properties. And the easiest one to grasp there is the one that comes out of a field called inflationary cosmology. So inflationary cosmology is in some sense an enhanced version of the Big Bang theory, which seeks to fill in a missing piece in the standard Big Bang proposal.
See, the standard Big Bang tells us how the universe evolved after the bang, but doesn’t tell us what powered the bang itself, and people have tried to fill in that gap, to try to figure out what drove space to rush outward in the first place, and a guy named Alan Guth, a great physicist now at MIT, in the 1980s was the first to propose that there might be a naturally occurring kind of cosmic “fuel” that would naturally force space to rush outwards, and he proposed that this would be what drove the bang in the first place. The interesting thing is, as people began to study that proposal in more detail, they found that this fuel that he had proposed — and others like Steinhart and Linde developed further — this fuel would be so efficient that it would be virtually impossible to use it all up, which would mean that in inflationary cosmology, the Big Bang giving rise to our universe would not be a unique event. There would be Big Bangs that happened before, there would be Big Bangs that would happen after, in various and far-flung locations, each giving rise to its own expanding domain, each giving rise to its own universe.
And when you study those universes in detail, you find that, indeed, particle properties can vary from one expanding realm to another. Those particle properties and various environmental influences can indeed make the laws of physics appear different from one expanding realm to another, so the variations in that version of the multiverse proposal can be quite, quite significant.
Wired: One of my favorite book series is the Chronicles of Amber by Roger Zelazny, in which there are characters who travel between parallel worlds, and they decide to carry swords with them rather than guns, because guns stop working very rapidly when the laws of physics start changing around you. What do you think about that idea?
Greene: Indeed, I would suspect that in those other worlds, things could be so different that not only would guns stop working, everything else might stop working too. So they prepared themselves well, but I think what they may not have taken into account is, if the laws of physics vary enough that guns and gunpowder don’t work, it’s probably the case that the laws are such, and they vary to such a degree, that the biological processes that keep us ticking would probably not be happening either.
Wired: If there was a material in a parallel world that couldn’t exist in our world — that different laws of physics produced — and you could take that material and bring it to our world, would it fall apart? Would it have special properties?
Greene: You know, you can imagine the simplest example of that, where perhaps the basic fundamental particles like electrons and quarks, maybe they exist in those other universes, but maybe their masses are a little bit different, or their electric charges are a little bit different, and that idea is quite compatible with the mathematical formulations that we have of these various multiverse proposals. Now, if you study the properties of matter, and how they depend upon the masses of the basic particles, and the charges of the basic particles, you find something spectacularly interesting. If you change the basic properties of the particles by even a little bit — change masses by 20 or 30 percent, or you change electric charges by 20, 30, 40 percent, you really disrupt the atomic structure that’s responsible for all those elements on the Periodic Table, and the way those elements would exist and combine and behave.
So even modest adjustments to the fundamental physical parameters would rapidly disrupt matter as we know it. So if you tried to take things from one place to another, they would themselves suffer radical disruption. You can imagine that maybe there are other universes where the changes are so slight that matter would suffer only the most modest of changes as it went from universe to universe — if indeed you could transport it from place to place — but in most of these multiverse proposals, the vast majority of the other universes would not be very close in these features to our universe, and therefore matter really could not survive that kind of journey.
Greene: The most well-studied explanation for how our universe could have more than three dimensions of space, how there could be so-called “hyperspace” and yet we don’t see those dimensions is indeed the one that you’re referring to: The extra dimensions are all around us, they’re just crumpled to such a fantastically small size that we can’t see them.
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Wired: How close are we to developing a teleportation device like the transporter in Star Trek?
Greene: Well, we’re pretty far. There are experiments going on today where individual particles are being teleported from one location to another. Now, this notion of “quantum teleportation,” which is what I’m referring to, is somewhat different from at least my rudimentary understanding of what the creators of Star Trek had in mind with the transporter. There, I think, the basic idea is the material that makes you up is somehow scrambled or broken up into little pieces, and it’s kind of sent through space and then reassembled at a distant location, on the surface of some distant planet. That’s not the kind of teleportation that physics seems to allow.
Instead, what happens in quantum teleportation is the object that you want to teleport is closely examined in one location, and all the information that defines that object is sent to the remote location, and that information is then used at the remote location to build what can be thought of as an exact duplicate of the object that you started with, so you might want to call that, I don’t know, “quantum Xeroxing” or “quantum faxing” or something of that nature. What makes this a little bit closer to teleportation is that you can establish that the act of measuring the original object destroys it. There’s no way that you can get at all the necessary information to rebuild it without disrupting its basic makeup to such a degree that it really wouldn’t exist any longer at the original location, so if I asked you where the object is, I think the best answer you’d give is, well, it’s at the remote location, because that’s the only object that looks like the original that I started with, since the act of measurement destroyed the original.
So that’s a version of teleportation. Again, it’s only being done with individual particles. Perhaps that will be bumped up to some collection of particles at some point, but it is utterly, utterly beyond the pale to imagine doing this kind of process with the number of particles that make up any macroscopic body like a person, or an object like a car. So I am tempted to say that we’re infinitely far away from teleportation of big objects, but that would perhaps be a little too pessimistic, but we’re nearly infinitely far away.
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Wired: You participated in the 2011 Isaac Asimov Memorial Debate, where your colleague Dr. Jim Gates explained that his recent research leads him to wonder if we’re living in the matrix [at 1:01:30 in the video at right]. What did you think about that?
Greene: I have no idea. You know, Jim is a great scientist, a good friend of mine. I’ve not really followed the ideas that he’s been pursuing of late, and just don’t feel qualified to comment on it.
Wired: There was something in The Fabric of the Cosmos where you said that there’s some evidence that our universe is in some sense of 3-D projection of information contained in a 2-D shell surrounding the universe? What was that all about?
Greene: Well, that’s a wonderfully weird collection of ideas that go under the heading of the “holographic principle.” It’s a collection of ideas developed over the last 30 or so years, initially starting with attempts to deeply understand the physics of black holes. Black holes, we all know, are these regions where if an object falls in it can’t get out, but the puzzle that many struggled with over the decades is, what happens to the information that an object contains when it falls into a black hole. Is it simply lost? You know, if I throw an iPad chock full of all sorts of wonderful apps and books that are on it, is all that information lost when it goes into the black hole or not? Now, Steven Hawking believes that the information is simply lost — it falls into a black hole, gets trapped inside, you’ll never see it again, and that’s that.
The problem is, there’s a pretty basic law of physics which convinces us that information can’t be destroyed. It can be scrambled, it can be transmuted, but ultimately it can’t be destroyed. And black holes seem to be flying in the face of that, and because of that tension a number of physicists — people like Leonard Susskind, Gerard ‘t Hooft, others — they tried to see whether the information might not really be lost.
And over the course of many years, they developed an idea that when an object falls into a black hole, yes indeed, it falls in, but a copy of all of its information content gets in some sense “smeared out” on the surface of the black hole, on the horizon of the black hole. Smeared out in some sense like a series of 0′s and 1′s, the way information is stored in a typical computer. And that idea would suggest that a three-dimensional object inside the black hole can be described by information on a two-dimensional surface that surrounds the black hole.
And it was a few years ago that string theory — the field that I work on — gave really strong evidence to many of us that this idea really might be correct. Now, the reason why that’s particularly interesting is because the space inside a black hole is not really fundamentally different — it isn’t governed by different laws than space outside a black hole, or space anywhere else, for that matter. So if we learn, as we seem to have, that a 3-D object inside a black hole can be described by 2-D information on a surface that surrounds it, that lesson should be quite general. Which means that 3-D objects, even the ones that we’re familiar with — you and me and everything around us — these 3-D objects may indeed be describable by information on a 2-D surface that surrounds us, a surface that in some sense is at the edge of the universe. Now, this starts to sound like a hologram; a hologram is a thin 2-D piece of plastic which, when illuminated correctly, yields a realistic three-dimensional image. The idea is we may be that three-dimensional image of this more fundamental information on the 2-D surface that surrounds us.
Now, let me just point out, this is a hard idea even for physicists who work on it every day to fully grasp. We’re still trying to really dot the i’s and cross the t’s and understand in detail what this would mean. But there are many who now take this idea very seriously, that we maybe a kind of holographic projection.
The Thing formed / built upon / defined by a non-Thing matrix of reality
Multiple themes of other localities of reality
Multiple themes that this reality is NOT the center of any of it
Multiple themes that energy cannot be created or destroyed – just translated or transmuted – into something else – born again
Could be