Hawking Radiation: Explaining the Evaporation Effect

In summary: The idea is that if you put a particle (or particles) into a black hole, it will disappear and leave only radiation. But, if you measure the radiation around the black hole, you might find that there is more radiation now than there was before the particle went in. That is because the "virtual" particle that disappeared has actually created two other particles in its place. It's like two people fighting and then one of them disappears. The person who disappeared created two other people who are now fighting.This whole thing about "virtual particles" to explain what is now called Hawking Radiation is just the only way he could think of to explain in English something that really only makes sense in the math.
  • #1
thetexan
265
11
I'm reading this article...

"Hawking proposed that the Universe is filled with 'virtual particles' that, according to what we know about how quantum mechanics works, blink in and out of existence and annihilate each other as soon as they come in contact - except if they happen to appear on either side of a black hole's event horizon. Basically, one particle gets swallowed up by the black hole, and the other radiates away into space." Science Alert

Even if that is true wouldn't that mean that there is one of the two particles trapped by the horizon? One particle being trapped and one escaping doesn't mean that the black hole is evaporating does it? It seems that there is a net gain of one particle adding to the mass of the black hole.

Can someone explain the evaporation effect please as it relates to the virtual particle theory please?

tex
 
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  • #2
thetexan said:
Even if that is true wouldn't that mean that there is one of the two particles trapped by the horizon?

That's right.

thetexan said:
One particle being trapped and one escaping doesn't mean that the black hole is evaporating does it?

Indeed it does.

thetexan said:
It seems that there is a net gain of one particle adding to the mass of the black hole.

The issue is that the mass of both particles comes from the mass of the black hole. So if one particle gets sucked up and one escapes then the black hole loses mass equal to the mass of the particle that escaped.
 
  • #3
Agreed, but, the notion of negative mass being inhaled by a black hole has always struck me as one of those spooky entanglement things.
 
  • #4
Many say that the picture of Hawking radiation that it involves virtual particle pairs is not necessarily a useful way to think of Hawking radiation. Hawking only suggested it as a way of picturing what is happening, not to be taken too seriously. Of course, you will never find any subject about which experts disagree more vehemently than what goes on in the vicinity of an event horizon! And the number two area of disagreement is the status of virtual particles, so this one's a double whammy. In fact, given the incredibly tenuous nature of the observational status of Hawking radiation, I think that topic must be after some kind of record for greatest amount of expert disagreement for something that is both most widely heard about by the general public and least likely to ever actually be observed coming from a black hole!
 
  • #5
Is the event horizon so precise of a sphere that it can split a virtual particle into two one which goes inward and the other which escapes?

Or is that a mid assumption on my part. If the sphere is fuzzy at its surface then it doesn't make sense to me.

tex
 
  • #6
It sounds like the sphere can't be fuzzier than the distance scale over which the uncertainty principle allows the virtual particles to virtually exist. Basically, if E is the energy of the particles, then the reckoning comes in a time roughly h/E, and the distance traveled in that time is ch/E if the particles are relativistic (they're usually photons). T is often very low, so E is very low, so the distance could be rather long. But I don't know if there's any theory about the fuzziness of an event horizon.
 
  • #7
thetexan said:
"Hawking proposed that the Universe is filled with 'virtual particles' that ...
Hawking has said that this whole thing about "virtual particles" to explain what is now called Hawking Radiation is just the only way he could think of to explain in English something that really only makes sense in the math. That is, it's an analogy, not an actual description of what happens.
 

1. What is Hawking radiation?

Hawking radiation is a theoretical phenomenon proposed by physicist Stephen Hawking. It refers to the radiation emitted by a black hole due to quantum effects near its event horizon, leading to a gradual "evaporation" of the black hole.

2. How does Hawking radiation explain the evaporation effect?

The evaporation effect refers to the gradual decrease in a black hole's mass over time due to the emission of Hawking radiation. This happens because the radiation carries away energy from the black hole, causing it to lose mass and eventually "evaporate" completely.

3. What causes Hawking radiation?

Hawking radiation is caused by the interaction between virtual particle-antiparticle pairs near the event horizon of a black hole. One of the particles falls into the black hole while the other escapes, resulting in a net energy loss for the black hole.

4. Can Hawking radiation be detected?

Hawking radiation is extremely weak and difficult to detect, as it is emitted in the form of low-energy photons and particles. However, with advanced technology, it may be possible to detect Hawking radiation from smaller black holes in the future.

5. What implications does Hawking radiation have for the future of black holes?

Hawking radiation suggests that black holes will eventually "evaporate" completely, with smaller black holes evaporating faster than larger ones. This has important implications for the lifespan and ultimate fate of black holes in our universe.

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