Leonard Susskind [Photo by Anne Elizabeth Warren]
CLR INTERVIEW: Leonard Susskind is the Felix Bloch Professor of theoretical physics at Stanford University. His new book, The Black Hole Wars, details his battles with Stephen Hawking over the true nature of black holes. The resulting theory postulates that every object in our world is actually a hologram being projected from the farthest edges of space. Seriously. Below is Dr. Susskind’s interview with the California Literary Review.
- The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics
- Little, Brown and Company, 480 pp.
Would you give us an overview of what a black hole is?
A black hole is what you get if you compress so much mass into a region of space that it collapses, under its own weight, to an infinitely small, dense, point called the “singularity.” Everything that gets too close to the black hole gets sucked in, and squashed beyond recognition. There is no escape from the singularity, even for a light ray. Someone falling into a black hole might try to send a message, on a beam of light, to the outside world: “Help, I’m being sucked in.” But even the light ray gets pulled back to the singularity.
There is a certain radius—a particular distance from the dangerous singularity—that I like to call “the point-of-no-return.” If you accidentally pass the point-of-no-return there is nothing you can do to escape; you and all your messages will get swept to the singularity and destroyed. The point-of-no-return is also called the horizon of the black hole.
Passing the horizon seems very innocent while it is happening. It’s like being in a rowboat above Niagara Falls. If you accidentally pass the point where the current is moving faster than you can row, you are doomed. But there is no sign—DANGER! POINT OF NO RETURN—to warn you. Maybe on the river there are signs but not at the horizon of a black hole.
Stephen Hawking once said something about black holes that apparently upset you. What was it?
Stephen said that when a bit of information falls into a black hole it is permanently lost to the outside, despite the fact that he also proved that black holes evaporate and eventually disappear. That claim touched off a crisis in physics, a clash of basic principles like no other since Einstein was young.
The problem that upset me is that the most basic principle of physics—the principle that underpins everything including classical physics, thermodynamics, quantum mechanics, energy conservation, that physicists have believed for hundreds of years—is that information is never truly lost. It can be scrambled beyond recognition, but it is never completely erased.
Hawking’s claim was outrageous, but he had very good reasons for it. So good that it took more than two decades to figure out why he was wrong. And the question led to a tremendous paradigm shift in the way we think about space, time, matter, and bits of information.
Why was this so important?
Well it’s probably not important for curing cancer, or knocking down enemy missiles, or speeding up your computer. But it is important to the future of physics and cosmology. The universe is controlled by two fundamental laws: Einstein’s gravity theory (the General Theory of Relativity) and Quantum Mechanics. Stephen argued very convincingly that the two (GTR and QM) were on a collision course. Gravity and Quantum Mechanics were just plain incompatible. One or the other would have to give, at least by Hawking’s logic.
Stephen was wrong, but his astonishing question has changed the history of physics, and there is much more to come.
So, what do you believe happens to matter sucked into a black hole?
Remember that in a monumental contribution to physics, Hawking showed that black holes evaporate, like puddles of water on a hot day. It happens very slowly but the black hole does emit particles, and eventually disappears. The answer is that the evaporation products—the photons and other particles—carry away every bit of information, BUT in an extremely scrambled form. What we have learned is that black holes are not information-erasers but information-scramblers.
What was the final outcome of your competing theories?
The short answer is that Stephen was wrong and I was right. But that is a tremendous oversimplification and I would not like history to see it that way. Stephen asked an audacious, bold, and very brave question —do black holes erase information? Just realizing that there was a question took profound insight. It was enough to make anyone’s reputation. The outcome was a whole new paradigm called the Holographic Principle. The Holographic Principle says something astonishing and completely beyond intuition. The world is a kind of hologram: an image projected from a distant mathematical film, far at the edges of the universe. To understand how we got from black holes to holograms you’ll have to read my book, but here is a hint. The horizon of a black hole (a two dimensional surface like a film) somehow stores all the information that ever fell into the hole.
Where does biology fit into a theoretical physicist’s thinking? Do the attempts at an elegant “Theory of Everything” include life’s impulse to survive and replicate?
Physicists don’t like to think that their science is anything like biology. Biology is messy, imprecise, and complicated. Physics is simple, crystal clear, and elegant, or so the argument goes. But physicists have been hit over the head with some “ugly” facts. There are powerful reasons to believe that the universe may also be a consequence of random mutation. It sounds crackpot, or at best, like fringe speculation, but by now the idea is very firmly established in the mainstream physics and cosmology literature. That’s was what my book “The Cosmic Landscape” was all about.
According to String Theory the tiniest dimensions of space are curled up and twisted into an analog of the Double Helix. The Double Helix is a frame on which base-pairs can be arranged. And as you know, the pattern of base pairs determines the properties of a given biological entity.
Microscopic space (according to String Theory) is not a Double Helix, but something similar: a Calabi Yau manifold (don’t ask). The analog of the base pairs of DNA are called “fluxes.” The details don’t matter. What does matter is that there exists an incredibly rich set of possibilities—you can call them blueprints—for the construction of a universe. And according to modern cosmological theory, the universe is filled with sub-universes of every allowable kind, formed from a process similar to random mutation.
If this is so then the question, “Why our universe is the way it is?” may have an “anthropic” component: we live in a very rare environment where the ordinary laws are such that life can exist. Where else would we live? Where else would it be possible to ask the question?
How about consciousness or awareness? Are there any physicists who see consciousness as a distinct but interwoven part of the universe?
I suppose there are. My own view is similar to Richard Feynman’s when he was asked whether the conceptual puzzles of quantum mechanics confused him. He said that quantum mechanics was so puzzling that he wasn’t even sure if there was a puzzle. There are other questions like that—questions that you can’t even imagine what an answer could be like. “Why does mathematics work?” “Why does logic work?” “What is the purpose of the universe?” “What is the connection between mind and matter?” As I said, these seem like legitimate questions, but you can’t imagine what answers would be like. My sense is that consciousness is one of those questions.
Incidentally, I don’t mean to imply that these questions will never get answers; just right now I don’t have a clue. But then again I am not a licensed cognitive scientist.
If I understand it correctly, you’ve recently written that our universe may just be one of an infinite number of universes, each with unique properties or laws of physics. Is this where you think our knowledge is headed and if so, do you find that discouraging or encouraging in terms of what we can ultimately know about the universe?
First of all I am not in the least bit alone in this view, nor am I the originator of it. It has been around for a long time. But since I wrote “The Cosmic Landscape,” it has practically become the conventional view.
As to whether I find it discouraging or not—no—not at all. There are people who do, but I think they are victims of their own prejudices and hopes. The universe is far more interesting and challenging than we imagined. The next generation of physicists and cosmologists will have the fun and excitement of discovering the right mathematical formulation of a “multiverse.” Finding observational (astronomical?) ways to confirm that we live in such a diverse world is another challenge. Only the old fogies who thought that physics was almost finished are disappointed. The only thing that I would find discouraging would be that we run out of questions.
Heard any good theoretical physics jokes lately?
Yup, and you’ll find them in my book.
Related articles:
Follow the California Literary Review on Twitter: @calitreview
July 8th, 2008 at 4:46 pm
[...] an interview with Susskind here about his latest book. About anthropics and the multiverse he claims …since I wrote “The [...]
July 9th, 2008 at 3:18 am
[A black hole is what you get if you compress so much mass into a region of space that it collapses, under its own weight, to an infinitely small, dense, point called the “singularity.”]
This is what Einstein’s gravity theory tells us. But it means that the theory is not consistent, for it predicts black hole and Big Bang “singularities”. Therefore, we don’t have a consistent theory predicting black holes. Thus, we are not really sure what black hole is, are we?
July 16th, 2008 at 3:05 pm
Multi universe is ridiculous, from the logical stance. If they, the Multi universe, exit and they have impact on our universe, then they are part of our universe and all the multi universes, include our, is one universe. If the other universes have not any impact on our universes than from our logical point of view they are not exit.
String theory is ridiculous theory. If the vibration is the practices and the energy than the stings themselves what they are? Mass? Energy? They must be something. If so you must to develop theory that explain them and the processes that occur inside them .If so you receive two kinds of mass, energy. The one is result of their vibrations and the second the sting themselves .from the logical stance we have logical failure.
In my point view unit theory must be totally mathematical abstract and not image, like the sting ( theory), of some things that exit in our surrounding world.
July 17th, 2008 at 5:55 am
@Hech Baan: You don’t fully make sense but it might be wise at this stage to point out that there are big differences between the singularity at the Big Bang and the singularity of a black-hole. For example, the former has a much higher energy (in fact all the energy of the universe) and it expanded thanks to cosmic inflation & dark energy. All of this is described in General Relativity.
@Dan Pasternak: In string theory, another universe only has an effect on our universe via. some very weak force(s)/coupling(s). I think two reasonable criteria that object A & B exist in the same universe are: 1) object A must have the possibility of interacting with object B via. the four known fundamental forces, and 2) there must exist a possible path for which object A can reach object B. Both of these are not satisfied if object A & object B exist in different universes of a multiverse described by string theory.
I would like to add one further comment to both. Although lively discussion on matters of particle physics & cosmology is most welcomed, I remind you that the most intelligent men & women in the past 100 years have analysed these problems thoroughly as a full-time occupation. It is very improbable, although not impossible, that someone sitting at home reading articles on the internet or watching documentaries can out-do their best efforts.
July 17th, 2008 at 8:38 pm
@Kent: According to Hawking & Penrose there is no much difference between Black Hole and Big Bang singularities. Moreover, the Universe expanded not because of cosmic inflation & dark energy, e.g. Friedmann models expand without inflation or dark energy. All of this is described in General Relativity (Hawking, Ellis – The Large Scale Structure of Space-Time; Misner, Thorne, Wheeler – Gravitation):-)
My point is simple: there is no consistent theory describing black holes. GR predicts singularities; therefore black hole is not a real solution. We believe it is very close to the “real” solution, but without Quantum Gravity we are not 100% sure.
Agreed with your last point.
August 14th, 2008 at 9:23 am
possibly the “singularity” is a single string. luckily the information is stored in the event horizont! when earth will be sucked up by the lhc black hole a type 3 race could recover us from there! only have to put a sign on the moon where we are to be found! hahaha!!!!
btw: thank you mister susskind for your lecture on youtube!
August 14th, 2008 at 1:16 pm
my brain is going to explode sometime soon. i really can’t comprehend how these people can fathom such insanely ridiculous/awesome/intelligent theories.
August 14th, 2008 at 2:36 pm
poor stephen hawking! leonard susskind kicked his …! no, just making fun…again! in fact he is one of the greatest! i saw him once (2002 or 3) live in munich talking about his book “universe in a nutshell” (is it called like this in the english edition?). very impressive…and funny! he ended with a joke about god stiching the universe with a needle like a balloon…what does this mean now????
September 6th, 2008 at 10:09 pm
fire up the supercollider and see if it has the answer
October 19th, 2008 at 2:46 pm
It will be fascinating to see what the LHC at CERN will reveal. By the way, Leonard Susskind has some great online video courses in physics. The trouble is, I’ve forgotten where they are.
Yours sinc… sinc… sinc-something-or-other
Jim ‘Hemispheres’ Memorizatron
University of Neurones
Britain
February 2nd, 2009 at 12:39 am
Hello. I am currently reading “The Black Hole War”, and there are a a couple of questions I have, if anyone can help me in simple language. I understand a black hole to be basically spherical in space/time. From this, I would have thought that the horizon was a ‘larger sphere’ (obviously not in a physical sense, but only as a mathematical shape) surrounding the black hole. I think I understand that the information lost into a black hole is stored in the horizon, but the area in which the information is stored is only a quarter of the area of the ’spherical’ horizon, which is exactly the area of a flat circle with the same radius as the horizon ’sphere’. Am I correct in this idea?
Secondly, I understand that if anything entering the region of a black hole actually passes the horizon, there is no way out. What then is Hawking radiation? Is this coming only from outside the horizon’s radius? If not, and there actually is radiation coming from inside the horizon’s radius, how does it escape?
Thanks.
April 7th, 2009 at 12:36 pm
Just as there are BLACK HOLES perhaps there are WHITE HOLES where the matter is being emitted out of as the black hole evaporates. This alone would go along with the physics principle that matter is not destroyed but only changes form.
There is another possibility that the matter drawn into a black hole is re-introduced into another universe of dimension where the two are in conjunction with each other. That is matter funneled into our black hole is poured out into some other universe or dimension. There for we should be looking for a point or place in our universe where matter is being “created.”
I would like to hear back from others who have similar ideas.
June 22nd, 2009 at 8:43 am
OMG, Mr. Drucker. I have been saying exactly what you said for years now. the fact that scientists have not postulated such a simple and elegant answer leads me to believe that you and I may just be ignorant… or brilliant!!
July 8th, 2009 at 12:59 pm
I would suggest that beliefs have to be transcended, then all of this stuff becomes clear. By that I mean, believing in things such as matter and non-matter, energy, motion, etc. and rather recognizing and fully realizing that there in fact are no such things will make things a lot less confusing.
August 19th, 2009 at 5:09 am
I never have favoured you greatly,clear Aristotle,with your studious eyes brow-bent to the earth,with your love of the hard smooth outline of stone,definite,precise..That which can be known,palpable to the hand or your methodic measurement,your method has known.But the exact definition remains what it always has been-an ideal,and a part of the hungry mind’s urge to know and possess,aloof and escaping the net. define me a bird.Have you got the electric,brief shimmer of wings,iridescent,antennae atrail,the swift,curving beak alert?What you define is a dead and glassy-eyed cage in a museum,without apulse of the spirit’s breathing.But the merit’s in striving;the meal’s joy is hunger.The struggle to make the unknown known is eternal;finiting the infinite kills it.When Plato,the thief of infinity,reached up to heaven with longing,snatched at its jewels,brought them to earth in his bosom,the instant he touched them the warm fire fled them,staying in heaven;left him with onyx and marble,a temple certainly,made lyric with his sighs of regret.But you,Aristotle,with your Macodonian zeal for mastery,you must conquer the whole known world and the best that one could say for you was that your logic seemed mere commonsense.You took the oriental splendour of riches and pronounced on them the irrevocable doom of a fossil museum.
October 24th, 2009 at 12:42 am
It was a great introductory book. Some of you people who don’t think so can write your own and than we’ll see who’s better. Like Fennyman said, “FIX IT”. I would like to know a relationship between Quantum fluctuation and time field.