The Cosmos

02
Sep

How big a deal was Stephen Hawking’s big black hole announcement?

“Can you hear me?” Stephen Hawking asked as he was about to begin his August 25 talk at the Royal Institute of Technology’s “Hawking Radiation” conference in Stockholm.

The 29-person audience, all VIP physicists, was eager to hear his big announcement and could hear him just fine. They knew, from a pre-announcement announcement the previous night, that Hawking was about to explain his solution to a 40-year-old mystery in physics: how information escapes from black holes.

But while his idea made big headlines, the mere nine minutes of explanation felt vague and confusing to other physicists.

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Artist's concept illustrates a supermassive black hole with millions to billions times the mass of our sun. Credit: NASA/JPL-Caltech

What is Hawking’s problem?

Hawking set out to resolve a problem called the “information paradox.” Understanding this snag requires a brush-up on black holes. If light or matter venture past a boundary around the black hole called the “event horizon,” they are done for: The speed required to overcome the black hole’s gravity and escape is greater than the speed of light. So anything that crosses the event horizon—and any information about what it was in its previous life—stays inside the black hole. Whether you, a Snickers bar, or a whole planet fall in, they all end up the same: as anonymous extra mass piled onto the black hole itself.

Or at least that used to be the idea. Then, in 1974, Stephen Hawking showed that black holes slowly evaporate. They continuously leak radiation (later named “Hawking radiation”), dwindling away until there’s nothing left, on timescales ranging form a few billion years to much longer than the current age of the universe. But, as theoretical physicist Carlo Rovelli of Aix-Marseille University, who attended the talk, explains, “This creates a problem: Where has all the stuff gone that fell inside? Where is the information about what fell in? It cannot be anymore ‘just inside,’ because the black hole has disappeared. So, where is it? Is it really lost?”

Quantum mechanics says that information about the stuff can’t be lost. Information can neither be created nor destroyed. But black holes seem to destroy it. But they can’t. But they seem to. That’s the “paradox” part of the information paradox.

Some scientists think the escaping Hawking radiation carries the information out with it, like a set-free hostage who can tell police about the room he just spent five days in.

Ideas abound about how that radiation might spill the beans, and Hawking’s new revelation is just one contender. “The situation is not that there is a big problem, and here is the solution,” says Rovelli. “The situation is that there is a big problem, and there are a dozen solutions … none totally convincing, and now we have a new one.”

Hawking’s big idea

On August 25, as Hawking sat before the esteemed physicists, his voice played through the room’s speakers. “I propose that the information is stored not in the interior of the black hole, as one might expect, but on its boundary, the event horizon,” he said, “in the form of supertranslations of the horizon.”

Translation: If you passed over the event horizon, you would leave an imprint on it. That imprint takes the form of, essentially, a hologram called a supertranslation—a two-dimensional representation of your three-dimensional parts—etched into the black hole’s exterior geometry. When Hawking radiation bubbles up, the event horizon leaves a similar imprint on that radiation. It’s like cosmic re-gifting. The Hawking radiation then streams back out into the universe, carrying the imprint, and the encoded information, with it. That code, though, is scrambled: If you fell into a black hole, we could not create your clone from it (sorry). But, cold comfort, your informational essence wouldn’t be eternally lost.

The idea that information could be stamped onto a black hole’s event horizon was first proposed by Nobel Laureate Gerard ‘t Hooft, and supertranslations—as mathematical ideas—come from the 1960s. We don’t yet know enough about Hawking’s idea to detail how new and different it is.

The problem with Hawking’s solution

And that’s part of the problem: According to colleagues, the details of his “solution” feel fuzzy. “Two big questions are where the information from infalling stuff gets deposited, and how that information later gets transferred to stuff leaving the black hole,” says Steven Giddings, a physicist at the University of California, Santa Barbara.

Those are two big questions—the biggest, most fundamental questions. It’s great that Hawking described the what of his idea, but, in science, the how is much more important. “What we need for a more detailed understanding is a more complete description of the mathematics … to see if they’ve really nailed the answer,” says Giddings. Rovelli agrees, stating, “The picture is very preliminary for the moment.”

They weren’t the only two left scratching their heads. “In the conference, there were many world-class physicists, including Nobel Prize winners,” says Joe Polchinski, Giddings’ colleague at UC Santa Barbara. “I didn’t perceive much enthusiasm about the new idea. Everybody was interested, of course, but I couldn’t detect anybody that appeared convinced.”

Polchinski, who has previously science-battled Hawking about black hole paradoxes, also pointed out a problem beyond the idea’s fuzziness: In Hawking’s scenario, information stays on the event horizon. But the information (using the previous example, you yourself) also falls into the black hole, meaning two copies of it would exist. “In quantum mechanics, information can’t be in two places,” Polchinski says, although he points out that Hawking may have found a way to evade this problem.

Because Hawking’s black-hole revelations (as well as his proclamations about aliens and religion) receive public buzz and papers called “AdS/CFT without holography: A hidden dimension on the CFT side and implications for black-hole entropy” don’t, it may seem that his idea is totally novel. But it’s not. “From what we here understand, his suggestion builds on ideas that people have been tossing around recently,” says Giddings. Rovelli and Polchinski also point out its similarity to ’t Hooft’s 1990s ideas, although Hawking has added “some technical steps.”

Hawking claims he, and co-conspirators Andrew Strominger of Harvard University and Malcolm Perry of Cambridge University, will leak more information in a paper in late September. If that paper throws around some convincing equations—what black-hole theorists require as evidence—the result could be a big deal. Until then, scientists are waiting to reserve judgment. “For the moment the theory is far too sketchy, in the manner it has been presented,” Rovelli says. “Let me put it this way: The big news is Hawking himself: his persona, his popular fame, the wonderful manner in which he communicate to the public and transmits enthusiasm to the public. This is fantastic and is his mastership. His physics is interesting, as many others’ are.”

Go Deeper
Editor’s picks for further reading

KTH Royal Institute of Technology: Hawking offers new solution to black hole mystery
Read a summary and watch video of Hawking’s August 25, 2015 talk.

Scientific American: Stephen Hawking Hasn’t Solved the Black Hole Paradox Just Yet
Clara Moskowitz tempers the buzz around Hawking’s August 2015 announcement.

The Washington Post: After a week of intense debate, Stephen Hawking and his colleagues are still puzzled by black holes
Rachel Feltman, who runs The Washington Post’s Speaking of Science blog, reports on the broader takeaways from the Hawking Radiation conference.

Tell us what you think on Twitter, Facebook, or email.

Sarah Scoles

    Bio Sarah Scoles is a science writer based in Berkeley, California. Her work has appeared in Popular Science, Discover, Motherboard, Aeon, and others, where she writes about the this planet, the edge of the universe, and the strange stuff in between. She studied astrophysics at Agnes Scott College and writing at Cornell University. Her hobbies include running on unkempt trails, biking across the Golden Gate bridge, visiting old telescopes, and reading the local newspapers of small towns. Follow her on Twitter and read more of her work here.

    • Colorado Native

      I’m just an amateur, but after reading a lot of these theories over the last few years, it seems that Occam’s Razor summarizes it all best: Where does all of the information sucked into a black hole go? It goes out the other end of a black hole…as a white hole, spraying matter, energy, and information back out into this universe somewhere/somewhen else. That’s my theory and I’m sticking to it. 🙂

      • quantum distress

        I’ve always thought that black holes were the big bangs for other dimensions.

        • Sorry, there are no other dimensions.
          There are no higher dimensions nor lower dimensions either.
          Everything is real.

          • David Eddy

            Good Friend,
            You are right in that dimensions are a human method for describing size. Size has no physical reality, but it does have real meaning which is a non-physical reality. What is a physical reality, is the fact that particles which are physical appear at one side of a barrier and then reappear at the other side of a barrier. This phenomenon proves that there are other planes of reality where physical things exist and that particles can move between other planes of reality. This phenomenon is happening at the particle level of physical reality. Many other anomalies happen at the human level of physical reality that have been sighted but not proved.

    • Dave Bryant

      The big catch is that black holes phase information in and out of our existence. Reality suggests that our ability to detect phased particles is limited, much like how light from your iphone in blocked by polarized sunglasses when turned sideways. Quantum information “seems” to blink in and out of existence because it exists in all probabilities at the same time. Simple, but not easy.

    • ScottRobinett

      Fascinating stuff. I like the evaporating theory, seems like a sound premise, but I’ll wait for the paper and the convincing equations…though I won’t understand them.

    • Justin Swanhart

      Here is the fix (grand unified theory)
      E=m(c*distance)^2
      G=E*1/distance^2

      Now time slows down in black hole, there is no singularity. No GR needed at all.

      • E is the equivalent of tension times length so that’s where to add a length (distance)
        http://www.pbs.org/wgbh/nova/blogs/physics/2015/09/how-big-a-deal-was-stephen-hawkings-big-black-hole-announcement/#comment-2233756279

        If you multiply c (which is meters per second) times a distance (length) your units will be off and it will not equal energy.

        Dimensions and units…
        mass = [M] = kilograms
        length = [L] = meters
        time = [T] = seconds
        frequency = [T^-1] = seconds ^-1
        speed = [L] / [T] …… = m/s
        acceleration = [L] / [T^2] …. = m / s^2
        momentum = [M] [L] / [T] … = kg_m / s
        force = [M] [L] / [T^2] . = kg_m / s^2
        energy = [M] [L^2] / [T^2] = kg_m^2 / s^2
        power = [M] [L^2] / [T^3] = kg_m^2 / s^3

        • Justin Swanhart

          Hi,

          C is in km/s and distance is km

          The speed of light increases with distance from mass inversely proportional to gravity, because both are related to how energy interacts with quantum foam, causing macro changes in the speed of light rather than quantum level changes.

          Essentially energy deforms space like it does in spacetime, but the space (quantum foam) has an equal opposite reaction to the energy, which we call mass.

          Orbits come from angular momentum transfer through the foam.

          The speed of light is faster on outside of spiral galaxy than inside, thus galaxy rotation problem. Mars travels a shorter distance close to the sun where time is slower (light is slower) and travels a farther distance away, which leads to the precession of mercury being higher. no frame dragging required.

    • ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      WHY THE SPEED OF LIGHT IS “C”
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

      There is a high tension string particle field in space (not the string theory type). Everything is connected by the particle field and it moves along with largest mass in proximity (something like what gravitational fields would be doing).
      A good 2-D model would be something like a spiders web (individual string lengths are approximately one Ångström).
      Now imagine an infinite 3-D spiders web. If a vibration was set off in it, it would travel forever and the speed the vibrations travel (through the net) is the speed of light (that’s actually what light is, a vibration traveling through a string particle field)
      The speed vibrations travel through the particle field is the speed of light “c”

      The particle field strings have a certain amount of tension, length and mass. That makes ‘c’ the speed it is. If the tension, length or mass changed so would ‘c’

      Here is a regular string tension formula…

      Tension = velocity squared x mass / Length.

      If we plug c in and rearrange we get…
      TL = mc^2

      Both sides of the equation are in joules or energy… equivalent to “E”.
      It means the Tension of the strings in space times their length is equal to their energy.

      This is why the speed of light is involved in Einsteins mass energy equivalence equation…

      E = mc^2

      …and actually why light travels at the speed of light…
      I always wondered why… now I know.
      It had to be something mechanical… tension and string lengths!

      So, you can arrive at Einsteins famous formula from completely different directions.
      You can think energy is contained in mass and released.

      E = mc^2

      Or you can think there is a particle field of strings and mass is inert, the energy is only potential… released (actually pulled) by tension on the strings.

      TL = mc^2

      They are equivalent. Which is correct? You do not know.

    • I think SH was right about the black hole info loss. Others ganged up on him and made him cave.
      QM is not a bible that needs to be meticulously followed.
      Some things might be explained almost correctly but that does not mean everything is.
      I could give 3 or 4 alternate and very plausible explanations for anything.

    • Raymond D

      I am amazed that all the articles I have read so far on this talk of “information” as if it is something that does not need to be defined or explained. What information?

      • I was thinking paper shredder (a BH analogy).
        It sucks a piece of paper in and shreds it up.
        Then if the shredded paper leaks out… it will leak out shredded.
        Same exact amount of stuff in and then out but if there were information on the paper it is — pooof — gone.

    • ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      ENERGY CANNOT BE OUT ON ITS OWN
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

      Everyone has the wrong idea of what energy, forces and fields are.
      Energy is a particle vibration or movement.
      You cannot have energy without a mass, energy is mass vibrating.
      Energy cannot be out on its own. (a supposed mass-less particle is a particle nonetheless, but there are no mass-less particles, so that’s irrelevant)

      Same thing goes for forces.
      A force is a group of particles arranged in a field pulling each other… and all of the particles absolutely have to be physically connected.

      A force (a group of connected particles) can only push very short distances and in rare circumstances like same pole magnets.

      But the point is… a force has to have particles involved.
      A force cannot be out on its own.

      Most of mainstream physics is a misconception.

      There is no such thing as pure energy.
      Again… Energy is a vibration on a particle (or particle movement).

      Can energy be converted into mass?
      Ummm… no, energy already has mass involved, it is a particle vibration or movement. There is no pure energy and you are not going to convert energy into mass.

      Think of a guitar string. If you pluck it… that is the energy. If you remove the guitar string from the scenario… can you still have the energy? No, of course not.

      Can you convert the guitar string vibration into mass? No… that is ridiculous.

      Look at what everything really is…

      Dimensions and units…
      mass = [M] = kilograms
      length = [L] = meters
      time = [T] = seconds
      frequency = [T^-1] = seconds ^-1
      speed = [L] / [T] …… = m/s
      acceleration = [L] / [T^2] …. = m / s^2
      momentum = [M] [L] / [T] … = kg_m / s
      force = [M] [L] / [T^2] . = kg_m / s^2
      energy = [M] [L^2] / [T^2] = kg_m^2 / s^2
      power = [M] [L^2] / [T^3] = kg_m^2 / s^3

      Notice mass [M] is not equal to energy [M] [L^2] / [T^2] …the vibration is missing

      Here is what Einsteins famous equation really looks like…

      [M] [L^2] / [T^2] = [M] [L^2] / [T^2]

      Energy already is a mass times speed^2.

      If you could just lop-off parts of an equation and claim whatever is left is equal… i.e. “energy equals mass” then you could also say that “power equals mass” and so does momentum and force. It is really stupid to think like that.
      Speed is NOT equal to length. Speed is equal to length divided by time.
      Energy is NOT equal to mass. Energy is equal to mass times speed squared.

    • MM

      the “artist’s rendition” is not showing a hole but an orb. a hole presumably would be flat on one side.

      • What makes you think the picture is of something spherical?
        I also think from no matter what angle you view a black hole (actually the event horizon) all you would see is a flat disc — actually just like a black circle. So that might be what is supposedly in the center of the picture?

        • MM

          In nature, especially in space, there would not be half a ball, everything spins and eventually becomes a ball shape, as far as we know a black hole is a hole not a bubble sitting on a plain. Although it is impossible for something to have no dimensions at all or we would see it.

          • The supposed event horizon is balled shaped (spherical). It just appears flat because absolutely no light is emitted or reflected.

            You can tell what shape or color something is by the light that is reflected and or emitted by it. That is NOT happening with the supposed black hole. It would be spherical but looks like a flat circle from any angle. i.e. even if you moved around it you would still just see a flat black disc from any direction.

            You need to think about it.

            • MM

              Not exactly because you can see space matter falling toward or being sucked into it so you would see the edge or closely surrounding matter. A funnel shape would make more sense.

            • No, the matter would be getting sucked in from every possible direction. A funnel cannot do that..

              But more importantly: the discussion was “if a black hole would look spherical or not.”

              If you can add more stuff into the argument as you go along… I would like to add topless babes on a beach in St. Tropez.
              Later

    • Kevin Pickle

      How is this different from Susskind’s solution?

    • David Eddy

      There is a major difference between physical reality and non-physical reality. Physical reality has substance and non-physical reality has no substance. The black hole would have an effect on the physical reality like stars but not on non-physical reality like information. Time is also a manmade concept not a physical entity.

    • I was thinking paper shredder (a BH analogy).
      It sucks a piece of paper in and shreds it up.
      Then if the shredded paper leaks out… it will leak out shredded.
      Same exact amount of stuff in and then out but if there were information on the paper it is — pooof — gone.

    • Nag Hammadi

      This is beautifully consistent with what the Nag Hammadi and correct religious doctrine teach. Black holes are the realm of the “unutterable” and the visible universe is the will of the “All” emerging from the realm of the unutterable. The governing dynamic of the visible universe is light, our portion of the “light” is described mathematically by the governing dynamic named; the Nash Equilibrium. Satan is the computer programmer who “created” our “reality” upon the framework God provided. Thus deluding himself into believing that he was God. He has since been corrected and has now jealously taken it upon himself to prevent us from returning to our Celestial home with God. The Savoir is the only way back. Fools mock, but they shall morn……

    • ~~~~~~~~~~~~~~~
      NO SINGULARITY

      ~~~~~~~~~~~~~~~

      Stuff cannot compress to infinity or infinite density.
      Matter is particles. Whatever gravity is… it is also connected particles.

      So you have particles connected to other particles by way of particles.

      Check image below… If matter is the red particles and gravity is the yellow lines (that would be supposed gravitons, also particles)… you can increase the strength (pull) of the yellow lines to a massive amount and it will pull the reds together, but it is not going to collapse the reds into a point. It will just hold everything together unbelievably tight.

      http://image.shutterstock.com/display_pic_with_logo/660631/106110071/stock-photo-crystal-lattice-structure-d-106110071.jpg

      NOTE: this was only an easy to understand example but that is how it is working.

      The strength of gravity doesn’t actually change too much, it’s the amount of connections that would vary the intensity in (for instance what they call) a black hole.

      Also, gravity is the weakest of the forces, correct?

      The strong force is much stronger but it is not collapsing the protons and neutrons in a nucleus. It just holds them together tightly. Got it?
      If the strong force cannot collapse matter, how is gravity going to?

      Think about it for 20 years if you have to.

      …..