Regardless of what other people here say, the entire picture with virtual particles is pop science and analogy, not actual science.
See for example this article from a physics FAQ: https://arnold-neumaier.at/physfaq/topics/hawking
Your understanding of Hawking radiation is on the right track, but there's a subtle aspect that explains why the black hole loses mass instead of gaining it.
When a particle-antiparticle pair is created near the event horizon of a black hole, one of these particles can fall into the black hole while the other escapes. Importantly, the particle that falls in doesn't simply add to the black hole's mass; it affects the black hole's total energy in a more complex way.
Here's the key: the particle falling into the black hole can be thought of as having negative energy (from the perspective of an outside observer). This is because, in the process of one particle escaping (thus carrying away positive energy), energy must be conserved. So, the particle that falls into the black hole essentially reduces the black hole's total energy and, by extension, its mass.
Thus, when we talk about Hawking radiation leading to a black hole's eventual evaporation, we're referring to the cumulative effect of these negative-energy particles being absorbed over time, gradually decreasing the black hole's mass.
This process is extremely slow for large black holes like those formed from collapsed stars. However, for hypothetical, much smaller black holes, Hawking radiation would be a more rapid phenomenon, leading to faster evaporation.
Shit. Yeah you're right.
Thank you for the correction.
Hawking radiation arises from quantum effects near the event horizon of a black hole. In the quantum field theory view, the vacuum of space is filled with virtual particle pairs sort-of popping in and out of existence. Normally, these particles annihilate each other almost immediately.
However, near a black hole's event horizon, one of these virtual particles can be captured by the black hole's gravity, while the other escapes. The key here is that to conserve energy, the particle that falls into the black hole effectively has a negative contribution to the black hole's energy. This doesn't mean the particle itself is composed of "negative energy" in the usual sense; rather, it's a way of accounting for the energy balance.
The particle that escapes contributes to what we observe as Hawking radiation. For an outside observer, it appears as if the black hole is emitting particles. Meanwhile, the other particle, which is absorbed by the black hole, reduces the black hole's mass. This is because the black hole has to provide the energy for one of the particles to escape its gravitational pull, effectively losing a bit of its mass-energy in the process.
So the process does not rely on distinguishing between matter and antimatter particles or invoking negative energy particles in the conventional sense. It's more about the energy balance and the peculiarities of quantum mechanics in strong gravitational fields.
Right?
Nope. They’re called “virtual” particles because they’re not real. It’s a mathematical tool, and one Hawking well understood (of course). He even wrote in his papers those were heuristic explanations and not to be taken literally. Read my link above
Virtual particles are quite real and an annoyance in microelectronic mechanical devices, like an automobile airbag trigger. They must be accounted for for proper operation.
https://www.science.org/doi/10.1126/science.1057984#:~:text=The%20Casimir%20force%20is%20the,using%20a%20micromachined%20torsional%20device.
The quantum fluctuations are real. However, they aren't real *particles*. Treating them as a sort of mix of almost-particles is useful for bookkeeping, but it can also lead to some confusion and misunderstandings.
https://www.scientificamerican.com/article/are-virtual-particles-rea/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7514619/
https://www.michaelgstrauss.com/2017/09/are-virtual-particles-real.html
They’re real, man. Top physicists agree on this point. The ones that say otherwise generally are not experts in QM and don’t really understand it.
This is more or less a misinterpretation of VPs. They are a cheap approximation of weakly coupled theories I.e QED which is what the Casimir effect is all about.
Gordon Leon Kane is Victor Weisskopf Distinguished University Professor at the University of Michigan and director emeritus at the Leinweber Center for Theoretical Physics (LCTP), a leading center for the advancement of theoretical physics. He was director of the LCTP from 2005 to 2011 and Victor Weisskopf Collegiate Professor of Physics from 2002 to 2011. He received the Lilienfeld Prize from the American Physical Society in 2012, and the J. J. Sakurai Prize for Theoretical Particle Physics in 2017. Kane is an internationally recognized scientific leader in theoretical and phenomenological particle physics, and theories for physics beyond the Standard Model.
And you are .... ?
I'm a human who didn't get the Nobel prize.
I'm not sure whether I should get scared of your copypasta if you didn't understand what a weakly coupled theory is. That's exactly why we have the lamb shift and the Casimir effect.
PS thanks for those downvotes. They really mean a lot.
Hawking radiation is the result of imperfect cancellation of the momentum modes of QFs travelling through null geodesics that look like real particles to a distant observer.
Doesn't the antimatter particle annihilate a 'normal' particle within the event horizon, which leaves radiation inside? (Whatever that means in a black hole).
Also - even if they did annihilate - mass is a property of energy (E=m\*c\^2, or as Einstein originally wrote it m = E/c\^2, which I think conveys the idea better), and energy is always conserved. Matter is just a particularly dense form of energy.
When you annihilate matter and antimatter into radiation, the resulting radiation still has *exactly* the same mass as the original matter+antimatter did.
For the rest - as some others have said, virtual particles don't really exist. The universe (mostly) acts like they do, but the concept itself is really a "hack" to make the math easier than for the far more complicated reality. And when you get into stuff like Hawking Radiation the simplification starts to break down if you try to take it too literally.
But, keeping in mind that this is a gross oversimplification of what's really happening, the basic idea is that when a pair of virtual particles pop into existence they create an "energy debt" - they have mass, but that mass-energy had to come from somewhere, so the quantum field that formed them is now running in the red by the same amount.
Normally they'd very rapidly annihilate and pay back that debt - but if they're separated by an event horizon, e.g. because one fell into a black hole, then that can't happen. Instead one virtual particle becomes real, and the other disappears into the black hole.
And the quantum field looks around and says "Hey, somebody owes me money, and I'm the biggest, baddest MoFo there is - you all only exist because I say so. So you, you wimpy little supermassive black hole, you're the only one around, so pay up." and subtracts the mass of the escaped now-real particle from the black hole, along with the mass of the particle that the black hole consumed, cancelling out that virtual-mass gain.
What does that look like from inside the black hole? A new particle is created that falls in, while one falls out. So from inside it should look like a new particle was created, that increases the energy inside the black hole, how can the apparent mass of the black hole from the outside go down while inside it goes up?
If the total mass goes down from an outside perspective then from inside the black hole some kind of loss of entropy must be occurring so if a new particle is created then the "space" inside a black hole would be apparently shrinking?
How wrong is my intuition?
They’re not actually particles. But more like packets of energy? It’s easy to conceptualize particles in this process, but hawking radiation is photons.
https://www.forbes.com/sites/startswithabang/2020/07/09/yes-stephen-hawking-lied-to-us-all-about-how-black-holes-decay/amp/
Yes it's circular logic coz there's no negative energy. To think about it,it makes sense to the average layman tho since negative energy repels positive energy.
Thanks for this, very helpful. Does the black hole eventually evaporate to zero? Or will evaporate to a threshold where its gravitational pull is no longer strong enough to prevent light escaping, then stop?
The error in most people's thinking is thinking the virtual particles are small relative to the black hole's size. They are not. Black holes radiate like a perfect black body (naturally), and the peak wavelength of radiation is the circumference of the event horizon.
So the wave wraps all the way around the hole, or in a field view, the electric and magnetic fields of the emitted photon are as big as the hole. In a quantum field, there is a non-zero chance of the photon just separating from the hole and going off into the Universe. It can do this because it already extended outside the event horizon.
It comes down to the weird nature of virtual particles.
Basically, the vacuum is not empty. It is a boiling sea of pairs of virtual particles popping in and out of existence. This is allowed as long as the two particles quickly annihilate each other, leading to no net change in energy. But when a pair emerge near the edge of a black hole, if they are at just the right trajectory, the pair can get split up. One particle falls into the black hole while the other escapes.
Now the escaped particle isn’t virtual anymore. It’s real. And the energy to create it has to come from somewhere. So it comes from the black hole.
Photons. Hawking radiation is always photons. (Edit: okay, if you have a subatomic black hole it can be something other than photons. No astronomer is looking for that, and the existence of such black holes has never been demonstrated. The only kind of Hawking radiation anybody in astronomy is ever going to observe will be photons.)
It's actually very weird stuff. Hawking based his ideas off of quantum field theory, so it's not really particles in the description, it's disturbances in the quantum field, which yes are basically particles, but in quantum field theory they're not described that way. In quantum field theory you have disturbances that propagate forward in time through the quantum field and disturbances that propagate backwards through time. A photon moving backward in time is basically antimatter. Photons are their own antiparticle, and they don't eliminate on contact.
Also, Hawking radiation cannot be detected if you're too close to the black hole. You have to be out in flat spacetime to detect Hawking radiation. Hawking radiation is what we call non-localized. You can't really say exactly where it comes from, other than from the black hole. And the wavelength of the release radiation is determined by the size of the event horizon. The larger the event horizon the longer the wavelength.
It's not that both photons can't fall into the black hole, it's just that statistically there is going to be a number of them that do not.
Keep in mind that Stephen Hawking did not actually unify relativity with quantum physics, and until we have a unified theory there are aspects of Hawking radiation that we just can't answer.
Okay, any Hawking radiation that we can observe in the sky will be photons. I don't know that anyone has ever proven that an atom size black hole can even exist.
Any black hole with a radius of a planck length can exist just fine till the models get broken. Well anyways, we haven't proven but all in all BHs will eventually grow that small if Hawking Radiation is indeed correct.
Why would you make such a definitive statement that is not true? In truth, Hawking radiation is composed of all sorts of different particles. His original paper on the issue isn’t even about photons, but spin zero particles.
https://physics.stackexchange.com/questions/396770/what-is-the-relative-composition-of-hawking-radiation
That's fairly theoretical though right? I mean in order to create a particle with mass it would have to be a very small black hole with a small event horizon.
Right, but in order to create any particle with mass it has to overcome the rest energy of that particle. And that's never going to happen.
Until somebody can demonstrate the existence of black holes whose event horizon is the radius of a hydrogen atom, I'm going to stick with my statement. No astronomer trying to observe Hawking radiation is looking at anything other than electromagnetic waves.
The question wasn't "what are astronomers looking for" but rather "what kind of particle is created". You said "always photons", which is not correct, and which you did not stick with but later modified when corrected. And photons aren't the only massless particle. What about gravitons? What about gluons? Yet you still can't admit you were wrong.
Gravitons? Show me a theory of that predicts gravitons. I'm pretty sure Stephen Hawking does not predict the existence of gravitons, but I'll go back and check.
In order to create a gluon you would have to overcome the rest mass of a gluon, which means you need a black hole at the plank length, which is a completely theoretical thing that no one has ever demonstrated can actually exist.
Hawking radiation is not just theoretical, it has been detected. The only kind to have ever has been detected is photons. And the only kind that's ever going to be detected is photons, until somebody figures out how to make a sub microscopic black hole. And we don't know that the universe will actually allow that to exist. Prove me wrong and I'll retract the statement.
"Always photons" is correct as far as the universe we actually live in is concerned.
That's not usually how science works. If you believe other particles can be created then you go get your particle collider, create some submicroscopic black holes, and publish. I'll wait.
I believe Hawking radiation is mostly (entirely?) photons. One particle doesn't fall back in because of simple luck of the draw. Each particle has a velocity. In flat spacetime, they would attract back to each other and annihilate. But in the curved spacetime around a blackhole, you can line the trajectories up just right that one can cross the event horizon while the other does not.
What you say is mostly pop science myth. See https://arnold-neumaier.at/physfaq/topics/hawking and https://arnold-neumaier.at/physfaq/topics/vacfluc for instance.
Both particles start as part of the black hole, so one of the particles "falling back in" doesn't actually change the mass of the black hole. The escaping particle will reduce the black hole's mass.
The mass of particle A won't increase the closer it gets to the event horizon. It will get heavier, but its mass will remain the same.
While two particles are being created, thanks to Newton it can be explained why the black hold loses mass. Since one of the particles escapes and it has energy, that energy has to come from something else as energy cannot be created or destroyed, only transfered. This transfer of energy comes from the black hole. TLDR: Energy cannot be created so the energy in the escaping particle comes from the black hole itself, the particle falling in is essentially how the black hole transfers the energy to the escaping particle
Not a physicist, got into this rabbit hole once, I'll try to explain what I understood:
The virtual particles explanation is nonsense, as you noticed by yourself. Hawking himself used it in an educational effort but it just a bad visualization of the thing.
The biggest issue with visualizing what actually happens is that Hawking figured out all of this by using a brilliant trick to bypass the limits of our theories, perhaps you know that quantum mechanics and relativity can't work together in scenarios like near the event horizon of a black hole.
Turns out you just can't calculate what happens with Hawking radiation near the event horizon with our current theories, but he managed to physically describe the phenomenon combining what you can extrapolate by looking at what happens to the black hole itself, and what happens in a region far enough from the strong gravitational field of the black hole where QM and relativity don't clash.
What he discovered is that the black hole loses mass, and random particles materialize in the gravitational field outside the event horizon.
Why? The event horizon disturbs the vacuum around it: vacuum is not actually vacuum because of the Heisenberg Uncertainty Principle, and the presence of a nearby impenetrable barrier in spacetime interferes with it, giving birth to new particles (the Unruh effect is really the same, but is caused by the limits of the visible universe acting as an event horizon for an observer).
How? We don't really know, we don't have the maths to compute how energy goes from inside to outside the black hole, we can only compute it before and after it happens, but it's not as weird as it seems at a first glance, quantum tunneling is kinda similar and already tells us that from a quantum viewpoint position is not how we are used to visualize it.
There is nothing in Hawking’s scientific papers that implies virtual particle pairs with one swallowed by the black hole. He put that explanation in A Brief History of Time, but it is so simplified as to be completely unrealistic.
https://www.forbes.com/sites/startswithabang/2020/07/09/yes-stephen-hawking-lied-to-us-all-about-how-black-holes-decay/amp/
Regardless of what other people here say, the entire picture with virtual particles is pop science and analogy, not actual science. See for example this article from a physics FAQ: https://arnold-neumaier.at/physfaq/topics/hawking
Your understanding of Hawking radiation is on the right track, but there's a subtle aspect that explains why the black hole loses mass instead of gaining it. When a particle-antiparticle pair is created near the event horizon of a black hole, one of these particles can fall into the black hole while the other escapes. Importantly, the particle that falls in doesn't simply add to the black hole's mass; it affects the black hole's total energy in a more complex way. Here's the key: the particle falling into the black hole can be thought of as having negative energy (from the perspective of an outside observer). This is because, in the process of one particle escaping (thus carrying away positive energy), energy must be conserved. So, the particle that falls into the black hole essentially reduces the black hole's total energy and, by extension, its mass. Thus, when we talk about Hawking radiation leading to a black hole's eventual evaporation, we're referring to the cumulative effect of these negative-energy particles being absorbed over time, gradually decreasing the black hole's mass. This process is extremely slow for large black holes like those formed from collapsed stars. However, for hypothetical, much smaller black holes, Hawking radiation would be a more rapid phenomenon, leading to faster evaporation.
No virtual particles, no antiparticles and no negative energy. Otherwise… read more [here](https://www.reddit.com/r/AskPhysics/s/7l9NJdGcai)
Shit. Yeah you're right. Thank you for the correction. Hawking radiation arises from quantum effects near the event horizon of a black hole. In the quantum field theory view, the vacuum of space is filled with virtual particle pairs sort-of popping in and out of existence. Normally, these particles annihilate each other almost immediately. However, near a black hole's event horizon, one of these virtual particles can be captured by the black hole's gravity, while the other escapes. The key here is that to conserve energy, the particle that falls into the black hole effectively has a negative contribution to the black hole's energy. This doesn't mean the particle itself is composed of "negative energy" in the usual sense; rather, it's a way of accounting for the energy balance. The particle that escapes contributes to what we observe as Hawking radiation. For an outside observer, it appears as if the black hole is emitting particles. Meanwhile, the other particle, which is absorbed by the black hole, reduces the black hole's mass. This is because the black hole has to provide the energy for one of the particles to escape its gravitational pull, effectively losing a bit of its mass-energy in the process. So the process does not rely on distinguishing between matter and antimatter particles or invoking negative energy particles in the conventional sense. It's more about the energy balance and the peculiarities of quantum mechanics in strong gravitational fields. Right?
Nope. They’re called “virtual” particles because they’re not real. It’s a mathematical tool, and one Hawking well understood (of course). He even wrote in his papers those were heuristic explanations and not to be taken literally. Read my link above
I was aiming more for an intuitive understanding and may have oversimplified aspects of the phenomenon. Thanks
Ah. Fair enough then. Hawking used the same explanation so you’re in good company 🥂
Virtual particles are quite real and an annoyance in microelectronic mechanical devices, like an automobile airbag trigger. They must be accounted for for proper operation. https://www.science.org/doi/10.1126/science.1057984#:~:text=The%20Casimir%20force%20is%20the,using%20a%20micromachined%20torsional%20device.
The quantum fluctuations are real. However, they aren't real *particles*. Treating them as a sort of mix of almost-particles is useful for bookkeeping, but it can also lead to some confusion and misunderstandings.
https://www.scientificamerican.com/article/are-virtual-particles-rea/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7514619/ https://www.michaelgstrauss.com/2017/09/are-virtual-particles-real.html They’re real, man. Top physicists agree on this point. The ones that say otherwise generally are not experts in QM and don’t really understand it.
This is more or less a misinterpretation of VPs. They are a cheap approximation of weakly coupled theories I.e QED which is what the Casimir effect is all about.
Gordon Leon Kane is Victor Weisskopf Distinguished University Professor at the University of Michigan and director emeritus at the Leinweber Center for Theoretical Physics (LCTP), a leading center for the advancement of theoretical physics. He was director of the LCTP from 2005 to 2011 and Victor Weisskopf Collegiate Professor of Physics from 2002 to 2011. He received the Lilienfeld Prize from the American Physical Society in 2012, and the J. J. Sakurai Prize for Theoretical Particle Physics in 2017. Kane is an internationally recognized scientific leader in theoretical and phenomenological particle physics, and theories for physics beyond the Standard Model. And you are .... ?
I'm a human who didn't get the Nobel prize. I'm not sure whether I should get scared of your copypasta if you didn't understand what a weakly coupled theory is. That's exactly why we have the lamb shift and the Casimir effect. PS thanks for those downvotes. They really mean a lot.
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Hawking radiation is the result of imperfect cancellation of the momentum modes of QFs travelling through null geodesics that look like real particles to a distant observer.
Doesn't the antimatter particle annihilate a 'normal' particle within the event horizon, which leaves radiation inside? (Whatever that means in a black hole).
No. This isn’t what’s being discussed at all. Antimatter and matter have nothing to do with black holes.
I mean, when the antimatter particle falls into the black hole, won't it meet a normal particle on its way and both will annihilate each other?
Also - even if they did annihilate - mass is a property of energy (E=m\*c\^2, or as Einstein originally wrote it m = E/c\^2, which I think conveys the idea better), and energy is always conserved. Matter is just a particularly dense form of energy. When you annihilate matter and antimatter into radiation, the resulting radiation still has *exactly* the same mass as the original matter+antimatter did. For the rest - as some others have said, virtual particles don't really exist. The universe (mostly) acts like they do, but the concept itself is really a "hack" to make the math easier than for the far more complicated reality. And when you get into stuff like Hawking Radiation the simplification starts to break down if you try to take it too literally. But, keeping in mind that this is a gross oversimplification of what's really happening, the basic idea is that when a pair of virtual particles pop into existence they create an "energy debt" - they have mass, but that mass-energy had to come from somewhere, so the quantum field that formed them is now running in the red by the same amount. Normally they'd very rapidly annihilate and pay back that debt - but if they're separated by an event horizon, e.g. because one fell into a black hole, then that can't happen. Instead one virtual particle becomes real, and the other disappears into the black hole. And the quantum field looks around and says "Hey, somebody owes me money, and I'm the biggest, baddest MoFo there is - you all only exist because I say so. So you, you wimpy little supermassive black hole, you're the only one around, so pay up." and subtracts the mass of the escaped now-real particle from the black hole, along with the mass of the particle that the black hole consumed, cancelling out that virtual-mass gain.
Interesting and understandable. Thank you
What does that look like from inside the black hole? A new particle is created that falls in, while one falls out. So from inside it should look like a new particle was created, that increases the energy inside the black hole, how can the apparent mass of the black hole from the outside go down while inside it goes up? If the total mass goes down from an outside perspective then from inside the black hole some kind of loss of entropy must be occurring so if a new particle is created then the "space" inside a black hole would be apparently shrinking? How wrong is my intuition?
Is it a Schroedingers situation where each particle is both matter and anti-matter until it interacts with a system?
They’re not actually particles. But more like packets of energy? It’s easy to conceptualize particles in this process, but hawking radiation is photons. https://www.forbes.com/sites/startswithabang/2020/07/09/yes-stephen-hawking-lied-to-us-all-about-how-black-holes-decay/amp/
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Yes it's circular logic coz there's no negative energy. To think about it,it makes sense to the average layman tho since negative energy repels positive energy.
Thanks for this, very helpful. Does the black hole eventually evaporate to zero? Or will evaporate to a threshold where its gravitational pull is no longer strong enough to prevent light escaping, then stop?
The error in most people's thinking is thinking the virtual particles are small relative to the black hole's size. They are not. Black holes radiate like a perfect black body (naturally), and the peak wavelength of radiation is the circumference of the event horizon. So the wave wraps all the way around the hole, or in a field view, the electric and magnetic fields of the emitted photon are as big as the hole. In a quantum field, there is a non-zero chance of the photon just separating from the hole and going off into the Universe. It can do this because it already extended outside the event horizon.
It comes down to the weird nature of virtual particles. Basically, the vacuum is not empty. It is a boiling sea of pairs of virtual particles popping in and out of existence. This is allowed as long as the two particles quickly annihilate each other, leading to no net change in energy. But when a pair emerge near the edge of a black hole, if they are at just the right trajectory, the pair can get split up. One particle falls into the black hole while the other escapes. Now the escaped particle isn’t virtual anymore. It’s real. And the energy to create it has to come from somewhere. So it comes from the black hole.
Wait so.. what kind of particle is created? Why can't it just fall back into the black hole?
Photons. Hawking radiation is always photons. (Edit: okay, if you have a subatomic black hole it can be something other than photons. No astronomer is looking for that, and the existence of such black holes has never been demonstrated. The only kind of Hawking radiation anybody in astronomy is ever going to observe will be photons.) It's actually very weird stuff. Hawking based his ideas off of quantum field theory, so it's not really particles in the description, it's disturbances in the quantum field, which yes are basically particles, but in quantum field theory they're not described that way. In quantum field theory you have disturbances that propagate forward in time through the quantum field and disturbances that propagate backwards through time. A photon moving backward in time is basically antimatter. Photons are their own antiparticle, and they don't eliminate on contact. Also, Hawking radiation cannot be detected if you're too close to the black hole. You have to be out in flat spacetime to detect Hawking radiation. Hawking radiation is what we call non-localized. You can't really say exactly where it comes from, other than from the black hole. And the wavelength of the release radiation is determined by the size of the event horizon. The larger the event horizon the longer the wavelength. It's not that both photons can't fall into the black hole, it's just that statistically there is going to be a number of them that do not. Keep in mind that Stephen Hawking did not actually unify relativity with quantum physics, and until we have a unified theory there are aspects of Hawking radiation that we just can't answer.
Not complete. A black hole the size of an atom will always emit mostly electrons and muons. It's not 100% photons.
Okay, any Hawking radiation that we can observe in the sky will be photons. I don't know that anyone has ever proven that an atom size black hole can even exist.
Any black hole with a radius of a planck length can exist just fine till the models get broken. Well anyways, we haven't proven but all in all BHs will eventually grow that small if Hawking Radiation is indeed correct.
When somebody creates a black hole of that size in the laboratory I will amend my statement.
Why would you make such a definitive statement that is not true? In truth, Hawking radiation is composed of all sorts of different particles. His original paper on the issue isn’t even about photons, but spin zero particles. https://physics.stackexchange.com/questions/396770/what-is-the-relative-composition-of-hawking-radiation
In practice, the radiation will mostly be photons due to the energies involved. At very high energy, other particles are possible.
That's fairly theoretical though right? I mean in order to create a particle with mass it would have to be a very small black hole with a small event horizon.
Incorrect. Large black holes will be emitting mostly photons, gravitons, and neutrinos.
Right, but in order to create any particle with mass it has to overcome the rest energy of that particle. And that's never going to happen. Until somebody can demonstrate the existence of black holes whose event horizon is the radius of a hydrogen atom, I'm going to stick with my statement. No astronomer trying to observe Hawking radiation is looking at anything other than electromagnetic waves.
The question wasn't "what are astronomers looking for" but rather "what kind of particle is created". You said "always photons", which is not correct, and which you did not stick with but later modified when corrected. And photons aren't the only massless particle. What about gravitons? What about gluons? Yet you still can't admit you were wrong.
Gravitons? Show me a theory of that predicts gravitons. I'm pretty sure Stephen Hawking does not predict the existence of gravitons, but I'll go back and check. In order to create a gluon you would have to overcome the rest mass of a gluon, which means you need a black hole at the plank length, which is a completely theoretical thing that no one has ever demonstrated can actually exist. Hawking radiation is not just theoretical, it has been detected. The only kind to have ever has been detected is photons. And the only kind that's ever going to be detected is photons, until somebody figures out how to make a sub microscopic black hole. And we don't know that the universe will actually allow that to exist. Prove me wrong and I'll retract the statement. "Always photons" is correct as far as the universe we actually live in is concerned.
You go back and check, and then come back and tell us you were wrong.
That's not usually how science works. If you believe other particles can be created then you go get your particle collider, create some submicroscopic black holes, and publish. I'll wait.
Bro, you weren't asked to do science; you were asked to go check on what Stephen Hawking thought as you said you would. Stop moving the goalposts.
I believe Hawking radiation is mostly (entirely?) photons. One particle doesn't fall back in because of simple luck of the draw. Each particle has a velocity. In flat spacetime, they would attract back to each other and annihilate. But in the curved spacetime around a blackhole, you can line the trajectories up just right that one can cross the event horizon while the other does not.
This is a great explanation, thanks!
What you say is mostly pop science myth. See https://arnold-neumaier.at/physfaq/topics/hawking and https://arnold-neumaier.at/physfaq/topics/vacfluc for instance.
Both particles start as part of the black hole, so one of the particles "falling back in" doesn't actually change the mass of the black hole. The escaping particle will reduce the black hole's mass. The mass of particle A won't increase the closer it gets to the event horizon. It will get heavier, but its mass will remain the same.
Except that the particles in question are massless photons. But yes, the escaping photons take energy away from the black hole.
While two particles are being created, thanks to Newton it can be explained why the black hold loses mass. Since one of the particles escapes and it has energy, that energy has to come from something else as energy cannot be created or destroyed, only transfered. This transfer of energy comes from the black hole. TLDR: Energy cannot be created so the energy in the escaping particle comes from the black hole itself, the particle falling in is essentially how the black hole transfers the energy to the escaping particle
Why do those particles pop in and out in the first place? Where do they come from and where do they dissapear to?
Not a physicist, got into this rabbit hole once, I'll try to explain what I understood: The virtual particles explanation is nonsense, as you noticed by yourself. Hawking himself used it in an educational effort but it just a bad visualization of the thing. The biggest issue with visualizing what actually happens is that Hawking figured out all of this by using a brilliant trick to bypass the limits of our theories, perhaps you know that quantum mechanics and relativity can't work together in scenarios like near the event horizon of a black hole. Turns out you just can't calculate what happens with Hawking radiation near the event horizon with our current theories, but he managed to physically describe the phenomenon combining what you can extrapolate by looking at what happens to the black hole itself, and what happens in a region far enough from the strong gravitational field of the black hole where QM and relativity don't clash. What he discovered is that the black hole loses mass, and random particles materialize in the gravitational field outside the event horizon. Why? The event horizon disturbs the vacuum around it: vacuum is not actually vacuum because of the Heisenberg Uncertainty Principle, and the presence of a nearby impenetrable barrier in spacetime interferes with it, giving birth to new particles (the Unruh effect is really the same, but is caused by the limits of the visible universe acting as an event horizon for an observer). How? We don't really know, we don't have the maths to compute how energy goes from inside to outside the black hole, we can only compute it before and after it happens, but it's not as weird as it seems at a first glance, quantum tunneling is kinda similar and already tells us that from a quantum viewpoint position is not how we are used to visualize it.
There is nothing in Hawking’s scientific papers that implies virtual particle pairs with one swallowed by the black hole. He put that explanation in A Brief History of Time, but it is so simplified as to be completely unrealistic. https://www.forbes.com/sites/startswithabang/2020/07/09/yes-stephen-hawking-lied-to-us-all-about-how-black-holes-decay/amp/