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The popular description of Hawking radiation with one particle from a virtual pair falling in and the other escaping is just a pretty picture (although Hawking uses it in a 1976 paper), "in another model, the process is a quantum tunneling effect, whereby particle-antiparticle pairs will form from the vacuum, and one will tunnel outside the event horizon". In fact, one does not even need the first particle to fall under the horizon. The radiation will still be observed if it just gets stuck asymptotically approaching it, while its companion acquires escape velocity and leaves the black hole's gravity well. The problem is that proper description must involve quantum gravity, which does not exist yet, since we have both quantum particles and very strong gravitational field in the picture.

What Hawking and others do is semi-classical gravity, where the metric is classical and described by general relativity, while radiation is quantized. Considering that such quantum/classical coupling is known to contradict the uncertainty principle (see Ricles, p. 37) one should not expect too much in the way of consistency in details, even if the result is qualitatively correct. For now, "tunneling" works. But considering how little the actual QFT picture of light propagation in a medium say, resembles both classical and semi-classical descriptions of that, it is likely that quantum gravity picture, when we have it, will be similarly different.

The virtual particle picture comes from Feynman diagrams in perturbative expansions of QFT. It is well known that gravity does not mix well with perturbative expansions because of divergencies (Ricles, p.46), so particle description may break down altogether near the event horizon. Alternatively, when gravity is quantized, the horizon may fluctuate like Wheeler's quantum foam and absorb particles that are classically strictly above it. It often happens that semi-classical calculations approximate the correct answer mathematically, but the physics they suggest is overly naive. We know that for modeling light in a medium, and for Bohr's model of the hydrogen atom for example.

The popular description of Hawking radiation with one particle from a virtual pair falling in and the other escaping is just a pretty picture (although Hawking uses it in a 1976 paper), "in another model, the process is a quantum tunneling effect, whereby particle-antiparticle pairs will form from the vacuum, and one will tunnel outside the event horizon". In fact, one does not even need the first particle to fall under the horizon. The radiation will still be observed if it just gets stuck asymptotically approaching it, while its companion acquires escape velocity and leaves the black hole's gravity well. The problem is that proper description must involve quantum gravity, which does not exist yet, since we have both quantum particles and very strong gravitational field in the picture.

What Hawking and others do is semi-classical gravity, where the metric is classical and described by general relativity, while radiation is quantized. Considering that such quantum/classical coupling is known to contradict the uncertainty principle (see Ricles, p. 37) one should not expect too much in the way of consistency in details, even if the result is qualitatively correct. For now, "tunneling" works. But considering how little the actual QFT picture of light propagation in a medium say, resembles both classical and semi-classical descriptions of that, it is likely that quantum gravity picture, when we have it, will be similarly different.

The virtual particle picture comes from Feynman diagrams in perturbative expansions of QFT. It is well known that gravity does not mix well with perturbative expansions because of divergencies (Ricles, p.46), so particle description may break down altogether near the event horizon. Alternatively, when gravity is quantized, the horizon may fluctuate like Wheeler's quantum foam and absorb particles that are classically strictly above it. It often happens that semi-classical calculations approximate the correct answer mathematically, but the physics they suggest is overly naive. We know that for modeling light in a medium, and for Bohr's model of the hydrogen atom for example.

The popular description of Hawking radiation with one a particle from a virtual pair falling in and the other escaping is just a pretty picture, "in another model, the process is a quantum tunneling effect, whereby particle-antiparticle pairs will form from the vacuum, and one will tunnel outside the event horizon." In fact, one does not even need the first particle to fall under the horizon. The radiation will still be observed if it just gets stuck asymptotically approaching it, while its companion acquires escape velocity and leaves the black hole's gravity well. The problem is that proper description must involve quantum gravity, which does not exist yet, since we have both quantum particles and very strong gravitational field in the picture.

What Hawking and others do is semi-classical gravity, where the metric is classical and described by general relativity, while radiation is quantized. Considering that such quantum/classical coupling is known to contradict the uncertainty principle (see Ricles, p. 37) one should not expect too much in the way of consistency in details, even if the result is qualitatively correct. For now, "tunneling" works. But considering how little the actual QFT picture of light propagation in a medium say, resembles both classical and semi-classical descriptions of that, it is likely that quantum gravity picture, when we have it, will be similarly different.

The virtual particle picture comes from Feynman diagrams in perturbative expansions of QFT. It is well known that gravity does not mix well with perturbative expansions because of divergencies (Ricles, p.46), so particle description may break down altogether near the event horizon. Alternatively, when gravity is quantized, the horizon may fluctuate like Wheeler's quantum foam and absorb particles that are classically strictly above it. It often happens that semi-classical calculations approximate the correct answer mathematically, but the physics they suggest is overly naive. We know that for modeling light in a medium, and for Bohr's model of the hydrogen atom for example.

The popular description of Hawking radiation with one particle from a virtual pair falling in and the other escaping is just a pretty picture (although Hawking uses it in a 1976 paper), "in another model, the process is a quantum tunneling effect, whereby particle-antiparticle pairs will form from the vacuum, and one will tunnel outside the event horizon". In fact, one does not even need the first particle to fall under the horizon. The radiation will still be observed if it just gets stuck asymptotically approaching it, while its companion acquires escape velocity and leaves the black hole's gravity well. The problem is that proper description must involve quantum gravity, which does not exist yet, since we have both quantum particles and very strong gravitational field in the picture.

What Hawking and others do is semi-classical gravity, where the metric is classical and described by general relativity, while radiation is quantized. Considering that such quantum/classical coupling is known to contradict the uncertainty principle (see Ricles, p. 37) one should not expect too much in the way of consistency in details, even if the result is qualitatively correct. For now, "tunneling" works. But considering how little the actual QFT picture of light propagation in a medium say, resembles both classical and semi-classical descriptions of that, it is likely that quantum gravity picture, when we have it, will be similarly different.

The virtual particle picture comes from Feynman diagrams in perturbative expansions of QFT. It is well known that gravity does not mix well with perturbative expansions because of divergencies (Ricles, p.46), so particle description may break down altogether near the event horizon. Alternatively, when gravity is quantized, the horizon may fluctuate like Wheeler's quantum foam and absorb particles that are classically strictly above it. It often happens that semi-classical calculations approximate the correct answer mathematically, but the physics they suggest is overly naive. We know that for modeling light in a medium, and for Bohr's model of the hydrogen atom for example.

The popular description of Hawking radiation with one a particle from a virtual pair falling in and the other escaping is just a pretty picture, "in another model, the process is a quantum tunneling effect, whereby particle-antiparticle pairs will form from the vacuum, and one will tunnel outside the event horizon." In fact, one does not even need the first particle to fall under the horizon. The radiation will still be observed if it just gets stuck asymptotically approaching it, while its companion acquires escape velocity and leaves the black hole's gravity well. The problem is that proper description must involve quantum gravity, which does not exist, since we have both quantum particles and very strong gravitational field in the picture.

What Hawking and others do is semi-classical gravity, where the metric is classical and described by general relativity, while radiation is quantized. Considering that such quantum/classical coupling is known to contradict the uncertainty principle (see Ricles, p. 37) one should not expect too much in the way of consistency in details, even if the result is qualitatively correct. For now, "tunneling" works. But considering how little the actual QFT picture of light propagation in a medium say, resembles both classical and semi-classical descriptions of that, it is likely that quantum gravity picture, when we have it, will be similarly different.

The virtual particle picture comes from Feynman diagrams in perturbative expansions of QFT. It is well known that gravity does not mix well with perturbative expansions because of divergencies, so particle description may break down altogether near the event horizon. Alternatively, when gravity is quantized, the horizon may fluctuate like quantum foam and absorb particles that are classically strictly above it.

The popular description of Hawking radiation with one a particle from a virtual pair falling in and the other escaping is just a pretty picture, "in another model, the process is a quantum tunneling effect, whereby particle-antiparticle pairs will form from the vacuum, and one will tunnel outside the event horizon." In fact, one does not even need the first particle to fall under the horizon. The radiation will still be observed if it just gets stuck asymptotically approaching it, while its companion acquires escape velocity and leaves the black hole's gravity well. The problem is that proper description must involve quantum gravity, which does not exist yet, since we have both quantum particles and very strong gravitational field in the picture.

What Hawking and others do is semi-classical gravity, where the metric is classical and described by general relativity, while radiation is quantized. Considering that such quantum/classical coupling is known to contradict the uncertainty principle (see Ricles, p. 37) one should not expect too much in the way of consistency in details, even if the result is qualitatively correct. For now, "tunneling" works. But considering how little the actual QFT picture of light propagation in a medium say, resembles both classical and semi-classical descriptions of that, it is likely that quantum gravity picture, when we have it, will be similarly different.

The virtual particle picture comes from Feynman diagrams in perturbative expansions of QFT. It is well known that gravity does not mix well with perturbative expansions because of divergencies (Ricles, p.46), so particle description may break down altogether near the event horizon. Alternatively, when gravity is quantized, the horizon may fluctuate like Wheeler's quantum foam and absorb particles that are classically strictly above it. It often happens that semi-classical calculations approximate the correct answer mathematically, but the physics they suggest is overly naive. We know that for modeling light in a medium, and for Bohr's model of the hydrogen atom for example.