<p>It is assumed in some explanations that Hawking radiation origins in virtual particle pairs getting real near the horizon of a black hole (the tidal force tearing them apart). But how can this be when there are no virtual photon pairs (as the photon is its own anti particle).</p>
<p>Do the photons simply emerge from real particles and anti-particles annihilating each other? The difference with Unruh particles that Unruh particles are not real (or existing only at infinity which is basically the same)?</p>

CC BY-SA 4.0
2021-06-24T12:21:45.257Z
The simplest answer is that the virtual particle pair explanation is a popular science explanation that doesn't actually work, a bit like how describing spacetime as a sheet of deformed rubber points out some useful things but also introduces extra confusion. Hawking explicitly calls it a popularization in his original paper (where he does introduce it, but after the real calculations).
Anders Sandberg
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2021-06-24T16:02:49.250Z
@AndersSandberg Are the photons drawn from the vacuum photon field? I dont see another way. Is the strong classic curvature inducing real excitations of this field? Negative energy photons, reducing the total energy of the black hole, being a real photon state?
Deschele Schilder
CC BY-SA 4.0
2021-06-24T17:18:41.767Z
Yes, the "real" explanation is a bit like the Unruh effect in quantum field theory: in accelerating frames observers can disagree on the number of particles belonging to a field, and this is why observers at infinity see the radiation.
Anders Sandberg
CC BY-SA 4.0
2021-06-24T17:24:55.757Z
@AndersSandberg The difference being that Hawking radiation is real (or at least can be seen at a finite distance)?
Deschele Schilder
CC BY-SA 4.0
2021-06-24T19:52:15.500Z
see [physics.se] https://physics.stackexchange.com/questions/37697/what-is-a-virtual-photon-pair
James K
<hawking-radiation>
How can Hawking radiation consist out of photons?
Deschele Schilder
# How can Hawking radiation consist out of photons?

(Asked by: username_0 on 2021-06-24)

It is assumed in some explanations that Hawking radiation origins in virtual particle pairs getting real near the horizon of a black hole (the tidal force tearing them apart). But how can this be when there are no virtual photon pairs (as the photon is its own anti particle).

Do the photons simply emerge from real particles and anti-particles annihilating each other? The difference with Unruh particles that Unruh particles are not real (or existing only at infinity which is basically the same)?

**Tags:** hawking-radiation

> **Comments:**
> **username_1**: The simplest answer is that the virtual particle pair explanation is a popular science explanation that doesn't actually work, a bit like how describing spacetime as a sheet of deformed rubber points out some useful things but also introduces extra confusion. Hawking explicitly calls it a popularization in his original paper (where he does introduce it, but after the real calculations).  
> **username_0**: @username_1 Are the photons drawn from the vacuum photon field? I dont see another way. Is the strong classic curvature inducing real excitations of this field? Negative energy photons, reducing the total energy of the black hole, being a real photon state?  
> **username_1**: Yes, the "real" explanation is a bit like the Unruh effect in quantum field theory: in accelerating frames observers can disagree on the number of particles belonging to a field, and this is why observers at infinity see the radiation.  
> **username_0**: @username_1 The difference being that Hawking radiation is real (or at least can be seen at a finite distance)?  
> **username_2**: see [physics.se] https://physics.stackexchange.com/questions/37697/what-is-a-virtual-photon-pair  

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