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Swapnil
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If black hole is so powerful, why doesn't it suck in Hawking radiation as well. I mean, it is just an electromagnetic radiation like light, right?
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pibomb said:...one particle will [...] fall in, while the other [escapes]
cesiumfrog said:If a particle-antiparticle pair were created from fluctuations in the external electromagnetic field, even if the antiparticle falls in it should only increase the contained mass-energy. Can someone elaborate on the explanation?
How does this explanation deal with the infinite time dilation for infalling objects observed by a remote observer?George Jones said:I wrote a bit about this in https://www.physicsforums.com/showpost.php?p=620350&postcount=4", and, more importantly I also gave a good link.
hellfire said:How does this explanation deal with the infinite time dilation for infalling objects observed by a remote observer?
I wonder if it is really possible to compute Hawking radiation in that way. For example, how do you calculate the rate of created / annihilated virtual particles per unit volume and time? From what I know about QFT you can compute probabilities, for example for the transition <0|0>. Calculating this you will only see what virtual processes contribute to this transition, but not the number density of them.Chronos said:Hawking radiation arises from the pure statistics of virtual particles popping in and out of existence at the event horizon. At least a few of them inevitably escape the maelstrom.
Chronos said:Hawking radiation arises from the pure statistics of virtual particles popping in and out of existence at the event horizon. At least a few of them inevitably escape the maelstrom. This a very subtle way through which black holes obey the laws of thermodynamics - there is no free lunch. Black holes are nearly, but not quite immortal.
I have posted this before but it fits well here too.Sariaht said:Let's say that a particlepair formed in "empty space", and that one of the particles was sucked in. What you are actually trying to say is that the particles obviously only passing by our roomtime, gets almost total room vector instead of whatever vector it had before, the thesis is that if the particles are lined, the outer particle might catch up with the inner particle, and if they collide, the photons they emit can escape the black hole. But since charged particles don't need room vektors to be able to emit energy, but a non roomly vektor that cut our room axis, that won't happen. But if you were talking about very small particles that through Heisenbergs relations happened to escape the black hole, because with the roomvektor it achieved in almost being sucked in, can excape through Heisenbergs relations, then it is impossible for the particle to stay in our universe for a longer time, since it can only get total roomvektor, if it is on the radius, and if it is on the radius, it cannot escape.
That is my oppinion, and I am entitled to express a such.
Labguy; in the past said:Chronos is correct about the mass-energy production of a black hole (BH) by way of Hawking radiation (HR). That is limited strictly to the "lifetimes" and energy release of a non-accreting black hole. Of course, a black hole with other matter being accreted will gain mass as long as the accretion rate exceeds the Hawking evaporation rate.
So, forget about a black hole sucking in matter of any kind and place it alone in a relatively empty region of space, at least empty enough to not draw in any nearby matter. This is where we can talk about the effects of Hawking radiation alone. The energy at the event horizon is as Chronos explained. This energy will produce virtual-particle (VP) pairs (from vacuum fluctuations outside the EH) and not just electrons/positrons as most often mentioned. The VP pair is produced by "borrowed" energy and must annihilate in ~10-30 atoseconds to “return” the energy. The Heisenberg uncertainty principle allows for two things. (1) It allows the VP pair to exist on borrowed energy for a finite, but very short, period of time, and (2) it allows the VP pair to be of any energy amount as long as, again, any "borrowed" energy is returned. Therefore, the VP pair is not limited to just electrons and positrons, it can also be quarks, protons, neutrons, and certain mesons regardless of energy required to produce the pair.
So, the virtual particle with negative energy falls into the BH and the other becomes a "real" particle with real mass. If it escapes into space (sometimes both will fall in), then the mass of whatever the escaping particle was will exactly match the mass-loss of the BH. Real mass is delivered into space as real particles. The BH loses that much mass, so the first two laws of thermodynamics are still happy, nothing has been violated.
so how does a small BH become so hot and evaporate so fast? Well, the "standard" HR process just mentioned was about one, single VP pair. In a large BH idling along this might be the case here and there around the EH. But, a smaller BH with more gravitational energy per squareanything will be producing VP pairs, of many different particle types, at a great pace. Now we have a swarm of real particles buzzing all around the EH at a very high density. Some will combine into more complex particles, but most will just escape or, to produce the intense energies mentioned, many particle-antiparticle pairs will meet and annihilate into pure energy. If the density is high enough and the particles massive enough, you will see the gamma-ray production so often mentioned, again, especially from small, short-lived BH's. Of course, it is actually the entire EM spectrum of photons that are produced but the gamma rays get the most attention.
Hawking Radiation is a theoretical form of radiation that is predicted to be emitted by black holes. It is named after the physicist Stephen Hawking, who first proposed the concept in 1974.
Hawking Radiation is thought to occur due to quantum effects near the event horizon of a black hole. Virtual particles are constantly being created and destroyed near the event horizon, but if one of these particles happens to be created outside the event horizon and the other falls into the black hole, the escaping particle becomes real and is emitted as Hawking Radiation.
The existence of Hawking Radiation suggests that black holes are not truly black, as they were previously thought to be. Instead, they emit a form of radiation that causes them to slowly lose mass over time. This has important implications for the lifespan and eventual fate of black holes.
As of now, Hawking Radiation has not been directly observed. It is a very weak form of radiation and is difficult to detect. However, there have been some indirect observations that support its existence, such as the decrease in mass of some black holes over time.
If Hawking Radiation is proven to exist, it could have significant implications for our understanding of black holes and the laws of physics. It could also lead to new theories and discoveries about the nature of space and time.