# Hawking Radiation and the Decay of Black Holes

by Logician
Tags: black, decay, hawking, holes, radiation
 Sci Advisor P: 6,077 The creation of a pair could be either way as you suggest. However, the one outside is still escaping from the black hole. If it is anti-matter it will encounter a matter particle outside and end up as a pair of photons. It is still a net decrease in the black hole mass.
 Thanks P: 1,948 You're confusing Antimatter with negative energy. The particles that fall in the black hole don't have to be antimatter. They are just as likely to be antimatter as to be matter. In fact the distinction between matter and antimatter is quite arbitrary. We chose to call electrons, protons, and neutrons matter and positrons, anti-protons, and anti-neutrons antimatter. but there is nothing fundamental about that choice. What's happening in the Hawking radiation is that the particles that fall in the black hole are virtual particles. The energy of real particles must satisfy two conditions. positive energy E > 0. and the dispersion relation E2 = (mc2)2 + (cp)2, where E is energy, m is mass, p is momentum, and c is the speed of light. In physicist's lingo these conditions are called shell conditions and real particles are said to be "on shell". The particles that fall in the black hole are virtual particles. They are not required to be on shell. In fact the ones that fall in the black hole must have negative energy because the ones that leave the hole have positive energy (they are real particles) and by energy conservation the total energy of the pair is zero since they appeared out of nothing and nothing has zero energy. Those negative energy particles fall in the whole therefore reducing its overall mass. Another misconception in your OP is the idea that there are particles inside of the black hole waiting to be annihilated. In fact there isn't anything inside of the hole except for the singularity at the very center. As particles fall in the hole they reach the singularity after a finite amount of time and than cease to exist. In fact there is no difference between a black hole created out of regular matter and a black hole created out of anti-matter. That's one reason it's known for sure that baryon number is not a conserved quantity - at least not in a black hole.
 PF Gold P: 6,353 Hawking Radiation and the Decay of Black Holes My understanding is that Hawking has said that the concept of "virtual particles" as an explanation for Hawking Radiation is an inexact analogy because the math does not lend itself to English. There are not really any particle-pairs involved, at least not in the way that you normally see described. I regret that I cannot give a citation for this but I believe it has been pointed out on this forum before.
Thanks
P: 1,948
 Quote by phinds My understanding is that Hawking has said that the concept of "virtual particles" as an explanation for Hawking Radiation is an inexact analogy because the math does not lend itself to English. There are not really any particle-pairs involved, at least not in the way that you normally see described. I regret that I cannot give a citation for this but I believe it has been pointed out on this forum before.
Yes, that is true. The virtual particles are a middle level explanation. Better than a hand wave but not as good as the real math.
P: 16
 Quote by mathman The creation of a pair could be either way as you suggest. However, the one outside is still escaping from the black hole. If it is anti-matter it will encounter a matter particle outside and end up as a pair of photons. It is still a net decrease in the black hole mass.
Is this creation in any way connected to quantum entanglement which Einstein dealt as spooking action at a distance in EPR paper.