Isn’t light just a form of radiation? How come it can’t escape, but other radiation can?
In: Physics
The pop-sci explanation is that virtual particle-antiparticle pairs are created and one part of the pair falls into the black hole and the other part escapes as radiation. This is how Hawking explained it in his book A Brief History of Time, but unfortunately, this explanation is too simplified to the point that it’s incorrect.
The correct explanation, as best as I can put it in ELI5 terms, is that the event horizon creates “boundary conditions” for the quantum fields that exist outside of the black hole. When I press my finger on a guitar string, it makes sure that the string isn’t moving there. That’s a kind of boundary condition, and it affects how the string vibrates. The black hole does the same kind of thing for the quantum fields that exist outside of it, and just like how pressing my finger changes the note my guitar plays, the black hole constrains the quantum fields so that radiation appears on the outside.
The mathematically-inclined reader can find Hawking’s original argument [here](https://www.brainmaster.com/software/pubs/physics/Hawking%20Particle%20Creation.pdf). To be honest I don’t understand it myself, but I take it on faith in my physicist friends that the explanation I just gave is more accurate than the usual pop-sci one. But it’s still at best an approximation of the actual math.
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