Mike2 said:
This goes along with a question I have about Hawking radiation and black hole dissipation. If the event horizon rips apart virtual pariticle pairs so that some escape to become Hawking radiation and the others fall into the black hole, then how can a black hole dissipate if half of those particles are continually falling into it? Wouldn't it continually gain more mass and hence never shrink?
Hi Mike
a couple things here...one is that the model of virtual pairs getting ripped apart at the horizon has been updated. A better idea perhaps is that there is a quantum uncertainty at the horizon which allows some particles to emerge.
and, IIRC, more mass makes the black hole event horizon smaller, not larger.
Seems to me we really have work to do to overcome our space and time prejudices. I made a beginning by imagining that the past and the future are real places, as solid as Chicago. Time as a landscape, where an imaginary being might be able to move at will from past to future or future to past. Of course we at this writing have no such freedom. We fall through time like a marble falls down a well, and have no volition to turn and go back.
What we do have, by virtue of our immense complexity and continual self-reference, is memory. We have the ability to remember what has just gone by. What is more, or perhaps the same, we have the ability to modify things that are falling with us through time in a way that allows us to communicate ideas to others who are falling...even to others who do not yet exist but may exist in our immediate future.
This ability to remember and communicate requires a certain level and a certain kind of complexity. We generally call this level of complexity consciousness, and the kind of complexity, intelligence.
You and I have some duration in time, but entropy demands that we dissipate. We can create some things that will outlast us. The museums are full of examples of how solid things degrade over time. Best of all we can create ideas, which exist beyond the limits of solid things, and can be reproduced through a wave-like motion of solid things, virtually forever. As long as there are solid things to carry the wave, anyhow.
Information is "like" a wave form in solid things. An encyclopedia carries lots of information. Of course the wave is not in the pages moving up and down or anything like that. It is more easily seen in the rather complex motions of people who pick up the encyclopedia and read or copy it. But information is to some degree less susceptible to the second law. Entropy must have an effect eventually, as information is dependent on material. But to a large extent, compared to the duration of, say, a stone statue covered in gold leaf and protected by a large marble building, information can endure where material cannot. So we know of the statue of Athena which stood for some time on the Acropolis, even though we cannot trace an atom of it today.
It is because information is less susceptible to entropy that we can get much less energy out of it. An encyclopedia falling into a black hole is not likely to have greater effect that an identical book composed of gray pages on which no information is present but the same number of atoms of the same kind do exist. If you burn an encyclopedia you do not get more heat than burning the gray book, and perhaps more to the point, you do not get any more heat from a new encyclopedia than you do from one that has been read, or copied, many times. We see that information of this kind is not directly coupled to entropy.
There remains the question of whether or of how much information is carried at the quantum level. In a sense, the coupling constant itself is a kind of fundamental information. The existence of mass has to be informational. The forces each have a fundamental relationship to spacetime, and that relationship must be informational. I think it is probably this kind of fundamental quantum information, for example of spin states, that is at question on the surface of the event horizon of a black hole. If a particle enters the event horizon of a black hole, does it leave a mark?
We may have to say that it does not leave a mark. Once the spin state dissappears into the event horizon, we have no way to recover the information of what kind of spin state it was. The quantum information is then lost to us forever.
Hawking radiation, and perhaps more importantly to us outside the black hole, Unruh radiation, returns some "information" back to us. A particle appears and we can measure its spin. However we cannot relate that particle that we can measure to any particle within the black hole...its appearance must be totally random. We cannot say that it is "the same" particle that fell into the black hole yesterday or five thousand years ago or at the beginning of our universe.
Black holes do radiate something, and Unruh radiation appears whenever any object moves even slightly. On average, Hawking particles and Unruh particles must cancel each other out. But sometimes, by quantum uncertainty, they do not cancel. Or at least, the cancelation has to be averaged over time, so that in a limited region of the space just outside the event horizon, there may be an uncancelled particle. For a while, at least. It may have some duration, but we know that eventually it will encounter its random opposite.
All the particles of the material universe are like that.
So now we can examine what we mean when we say that a particle is "the same", that is, has duration, from one instant to the next. We see right away that if time is indeed a landscape as I have described that particles do not have identity from one instant to the next. Instead, in time, we see a string of similar particles extended in the landscape of time. These particles in a string are most definitely not all the same. Particals retain some definite charachtor over time, but they also have the property of change over time. Let us not imagine anything complex, like say an atom or even the nucleus of an atom, made of many parts, but instead focus on the simplest particles, which so far as we know are unitary and have no discernable parts at all. Electrons. Muons. Nutrinos. Quarks.
In nuclear reactions we explain the changes by saying that quarks can undergo certain changes in color. Of course we are not talking about color as we see it in a sunset. Physicists wanted to be cute and poetic and chose to call a certain property of quarks "color", as a sort of metaphore, but in fact it has nothing whatever to do with the various wavelengths of light.
What we do see is that quarks undergo a structured sort of change, not in an entirely random way, but in a way that we can speak of a quark changing from one color to another color. We can set equations and balance reactions, based on the idea that it is the same quark, only haveing undergone a color change.
Neutrinos are thought to undergo changes also, as they travel through space and endure time.
Consider the time landscape for a single particle, let's say a neutrino. We will imagine it is isolated for the time we want to consider. We could model it by thinking of a string of beads, each bead representing the particle in an instant of time. If we choose our time difference carefully, based on the velocity of the particle, we can make the beads quite discrete, even though we know that there is really an underlying continuum. Think of a marble rolling across a gentle incline under a strobe. If we hold the shutter of a camera open, we can adjust the strobe so that we see the marble each time it has moved one diameter. That is the string of beads. Notice that there isn't any actual material string holding the beads, or marbles together. It is just a trick of the lighting, an adjustment of our consciousness, that allows us to see it displayed in this way.
Now the marble may be black on one side and white on the other. As we see it roll, we see it appear to change, even though we know it is the same marble. So we can relate the marble through successive instants and say that even though it changes, it is the same marble. Can we do this for fundamental particles also?
The fundamental particle moves through Planck space, and the strobe is replaced by the Planck time. Planck space and time are quantized, so that we must think of the movement like the movement of a checker on a game board. It occupies successive positions, not a continuum. Does it make a difference if we replace the checker with a different one? What do we mean when we say that the checker in one space is "the same" as the checker in the adjacent space?
In spacetime, when we say that the particle is the same as it traverses space, what we mean is that it occupies adjacent spaces, the other spaces around it being empty. In spacetime, what we mean by "a particle" is the line of adjacent particles. Clearly the adjacent particles are not really the same. They occupy different spacetimes. We can display them in a row.
Now we must ask what causes particles to appear in a row, that is to have duration, in spacetime? We have the twin examples of Hawking radiation and Unruh radiation, where duration of a particle is due to the random local occurance of particles that for a time do not encounter their random opposite. We may even say that time is created between the occurance of an isolate partner and the occurance of its opposite.
I have written myself out for the moment, and I don't know if I have answered any questions, or if I have made any questions better, by my rambling. I hope that some readers may find some use for this meditation, or that it may inspire further waves in the material consciousness that we inhabit.
Be well,
Richard
entropy entropy ...
