MICHELLE THALLER: Black holes are really coming to the real heart of our physics. And I think they show us how we will eventually need different physics and new physics. People ask questions like “What’s going on inside a black hole?” Or even “What happens on the edge of a black hole, the horizon of events, when light is absorbed?” And honestly, our physics are telling us many contradictory things. And our image of what is really an event horizon could change. People like Stephen Hawking and Leonard Susskind recently had the idea that a black hole shouldn’t be able to destroy information. O.K., what do we mean by information? Information can be practically anything.
All the different atoms in my body have an angular momentum, they have a charge, they have a mass. There is all sorts of little information that makes me. At the level of quantum mechanics, the smallest of the levels, there are different quantities of energy, there are different probabilities that are contained in the structure of my matter. And information, in some way, is a form of energy. It is actually a way in which you can describe something that is somehow, in a strange way, a higher state of energy than not being able to describe something. And so one of the questions is: “If energy can’t really be destroyed, energy itself is something intrinsic in the universe, you can’t really create or destroy, is it possible that information is the same way? Does it really exist there is no way to actually destroy information about what all my subatomic particles are doing right now? “
So black holes stare right at you. What supposedly makes a black hole is that it absorbs everything. Space and time fold into a black hole so that nothing can escape. This means that any information on the material that has fallen has disappeared. The only thing we know is that when a black hole absorbs material, it becomes more massive. It actually adds that mass to the black hole mass. And as that mass grows, the horizon of events gets bigger. Basically, the area where the space is so curved that you can’t get out of it starts to extend more and more a black hole is huge. The largest black holes we know of in the universe are billions of times the mass of our sun. And the physical extent of this event horizon is about the size of our solar system, perhaps like on the planet Pluto.
So is it possible, then, if everything goes into a black hole and nothing ever comes out, space and time go inside the black hole and don’t come out? What happened to that information? And this started to make many people think if we really thought about black holes the wrong way. Perhaps there is no event horizon in the true sense. I actually had a friend of mine who studied black holes and said, “Well, I’m not sure they are black. They could be a very, very dark navy blue.” And what he meant to say is that maybe there are a few tricks to actually get information from a black hole. Maybe there really is some form of energy that can escape from the black hole over time. Now Stephen Hawking wondered if quantum effects very close to the event horizon could actually separate something called virtual particles, the energy of space itself. If you are familiar with Einstein’s equation, E equals MC squared, energy equals mass by the speed of light squared. Energy and mass are the same thing. They are equivalent.
You can actually turn mass into energy and you can turn energy into mass. Around a black hole, where there is very hot gas, very high temperatures, very strong magnetic fields, perhaps there is a lot of energy. And that energy can actually manifest itself as particles, mass. And energy always creates particle / antiparticle pairs. They are called virtual particles. And matter and antimatter, the thing you know is that it annihilates immediately. So these tiny particles are born, then annihilate and return to energy. And this always happens around us. So if this happens near a black hole, it is possible that one of these small particles could penetrate the black hole and the other escape. And suddenly, there is a particle that shouldn’t be there. The universe basically has a new particle, energy from nothing. And how can it work?
And information theory people say that what happens is that energy has to come out of the black hole. The mass of the black hole starts to decrease if there is this poor little orphan particle that shouldn’t have been there in the first place. So over time, tiny particle of tiny particle, these black holes can evaporate. And maybe there is something about those virtual particles that contain some information about the black hole and what has fallen into it. It also becomes stranger than that, because many people think that time goes slower and slower as you approach a black hole, until, on the horizon of events, time basically stops. So instead of anything that really falls into a black hole, the event horizon could be a kind of information shell.
Things stop in time as they fall into the black hole. And right on that border, there is almost a kind of sphere, a two-dimensional surface that somehow contains all the information about what is inside the black hole. And this reminded people of something that humans invented, called a hologram. Now, a hologram is a two-dimensional object. You can do it with glass or a piece of film. And you illuminate a light through it, and suddenly, there seem to be three-dimensional projections. And the idea is that we are observing a fundamental way in which the universe stores information. Around a black hole, where space and time have been swept away from existence, could there be a shell of information, something like a hologram?
And many people have started to wonder, maybe that’s how the universe works on a large scale. Perhaps black holes are showing us, intrinsically, what is the underlying nature of reality, that there really is a two-dimensional surface of something that contains all the information about the entire universe. Maybe somehow, we are part of this giant hologram. And I should mention that the word hologram in no way implies that someone created the hologram. We are only talking about the universe that could really be information contained in a two-dimensional structure, not the three dimensions of which we are now aware. This all sounds incredibly strange. I’m always a little afraid of even talking about it. But I think the thing that can really gain from this is that black holes are staring at us. Now we are watching them.
They are right there. And we can’t really describe how the universe should work with one of these things. They don’t make sense. The universe shouldn’t be able to lose information. So how do you get information when the space itself is folded and nothing comes out? Black holes can be the key to reaching the next physics. We all know that we need a neighbor Einstein, a forthcoming quantum theory, something that actually describes how gravity works in very intense situations like a black hole. Now we are looking at black holes pretty well that we really have to go about this. We really need to understand how the universe works around one of these things. And we may end up learning what the universe itself really is.