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Name: Christopher
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Question:
Regarding Hawking Radiation, the usual description is that one member of a virtual particle pair enters a black hole, leaving it's orphaned partner roaming our universe, appearing to have been radiated out of the black hole. If two such processes take place, the first orphaning the virtual matter particle while the second orphans the virtual antimatter particle, can these two orphans meet and annihilate each other? If your answer is "yes" this suggests Hawking Radiation is only a temporary phenomenon, awaiting only sufficient time for all orphan / anti-orphan particles to either: meet and vanish, or vanish into a black hole which need not be the same black hole into which its original pair creation particle vanished.



Replies:
Christopher,

The one fault in your analysis lies in your interpretation of probabilities. Your analysis assumes that every particle, given enough time, will eventually meet up with every other particle in the universe. If a virtual antiparticle exists, it will eventually meet up with a virtual particle of the same kind. It is quite possible for an event to have less than 100% chance of occurring over infinite time. If not, then one could conclude that EVERYTHING has a 100% chance of occurring, given enough time. This then leads to the conclusion that everything that CAN happen eventually WILL happen.

A simple example that such an interpretation is incorrect lies in radioactive decay and half-lives. Within a second's time, a radioactive particle has a certain probability that it will decay. If this is 50% per second, we cannot say that the probability is 100% after 2 seconds. Should the particle survive one second, then there is only a 50% probability that it will decay during the next second. Should it survive the 2nd second, there is only a 50% probability that it will decay during the 3rd second. This continues on. A radioactive particle does not ever have to decay. If you have 100 million such particles, the odds are quite high that half of them (50 million) will decay during the first second. It is quite likely that half of what remain (25 million) will decay during the 2nd second, and so on. This pattern continues so long as there are a very large number of particles present. There is always a chance that no particles will decay in the first second, but it is not likely to occur. When you get down to the level of individual particles, probability behaves quite differently. It is truly random.

One can never say that something with less than 100% chance of happening will definitely happen. This is one of the properties of quantum physics that Albert Einstein could not bring himself to accept. You cannot say that the antiparticle will meet a corresponding particle. You cannot say that it won't. And even if they do come close together, you cannot say that they will interact. That too is based only on probability.

Dr. Ken Mellendorf
Physics Instructor
Illinois Central College


This is not my area of expertise, but your propositions seem reasonable. The probability of virtual anti-matter particle and a matter particle meeting in space-time, while not zero, would be quite small it would seem. The same is true, I would think, for the virtual anti-particle encountering a star, another black hole, etc. would also be very small. What is unknown is whether matter particles, e.g. electron itself, has a finite lifetime. Yes it is long, but it may not be infinite. These very fundamental questions await answers.

Vince Calder



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