Explain Hawking Radiation to me please
1) As far as I understand, the radiation is caused by particles with negative mass falling into the event horizon while the particles with positive mass escape. Shouldn't particles with negative mass escape just as often as positivie particles, thus cancelling out the effect?
>particle approaches EH
>gravitational energy about memehole
>virtual pair created due to energy imbalance
>both particles fall in = no radiation
>only one particle gets holecucked
>other virtual particle gains energy
>flies away, energy stolen from memehole
>e=mc^2
>memehole loses mass
this didn't help me at all
Virtual particle pairs are constantly being created near the horizon of the black hole, as they are everywhere. Normally, they are created as a particle-antiparticle pair and they quickly annihilate each other. But near the horizon of a black hole, it's possible for one to fall in before the annihilation can happen, in which case the other one escapes as Hawking radiation.The smaller the black hole the more accelerated it's degeneration will be as it has a smaller mass and therefore a smaller gravitational pull.
no, nigga
the particles with negative mass move backwards in time
doy
>Virtual particle pairs are constantly being created near the horizon of the black hole, as they are everywhere.
>Normally, they are created as a particle-antiparticle pair and they quickly annihilate each other.
>But near the horizon of a black hole, it's possible for one to fall in before the annihilation can happen, in which case the other one escapes as Hawking radiation.
>The smaller the black hole the more accelerated it's degeneration will be as it has a smaller mass and therefore a smaller gravitational pull.
Imagine your a virtual particle pair. And an antiparticle starts trolling you. You could keep responding, or just close the webpage, thus escaping the black hole that is Veeky Forums. Then a paralyzed guy in a wheelchair writes a paper about you.
Here's the deal: DON'T imagine the one particle going in as having negative mass. There is no such thing as negative mass, that's not how it works. What is created is a virtual particle/antiparticle pair (say, a positron and electron). Those have a mass (positive), and usually they would directly annihilate so that this energy fluctuation would cancel out again. Because of the event horizon however which sharply cuts off one particle from the other, the escaping particle is basically forced to exist. What has been just a little vacuum fluctuation, is suddenly a full fledged particle with mass, energy and momentum. Where did the energy to create this particle come from? The only possibility is from the black hole's energy (=mass).
So there are no negative mass particles, they don't exist. It's always positive mass particles, just that one vanished and the other escapes. To even out energy conservation, the mass of the black hole is lowered.
How does the memehole lose mass? The particle that flies away gains the mass on the particle that entered, so there is no net gain or loss for the memehole.
>imagine you have a video game that randomly spawns two cares near each other that are attracted to each other, and when they hit each other they disappear
>suppose there is a cliff, one car spawns on it and the other spawns right off it, but it can't drive so it falls down before the other can even react, so it drives away
>similarly, space is full of "virtual" particles and antiparticles soup
>sometimes, energy will randomly become a particle and anti particle pair, then annihilate to become that same energy amount because probability n shiet, so no net change happens
>but if one births inside the black hole's event horizon and the other just out, one can fall in and the other not, so there is kinda net change, so that energy from the black hole is lost by the mass
If you're OP, you ask a question with a false premise. Hawking radiation is not caused by particles with negative mass which enter the blackhole. It comes from outside the black hole.
I'm assuming this explanation doesn't translate to you because you don't know what a virtual particle is. A virtual particle isn't actually a particle, moreover we use them to explain minute fluctuations in fields in a manner which energy is conserved. If those fluctuations aren't minute, it's a "real" particle.
The distortion of spacetime about an event horizon gives rise to virtual particles, as this distortion influences the fields which permeate the given space.
If the pair annihilates, then it's basically like nothing ever happened, because they aren't real particles. However, if only one of the virtual particles falls in, the other half of the pair has nothing to annihilate with, and thus is forced to exist for a longer amount of time. The minute fluctuation lasts long enough for it to be considered a "real" particle. Now, it takes energy for a fluctuation to occur, and since the fluctuation only occurred due to the gravitational energy of the black hole, this is the energy that is displaced for this fluctuation to continue occurring.
The process steals gravitational energy from the black hole, thus it's mass decreases.
Because the initial pair was virtual, and the resulting particle is real. That takes energy.
So virtual particles only exist in pairs?
OP. This is a good explanation.
I would disagree that a virtual particle isn't a particle. I mean in the classical sense, sure, but in the quantum sense it's very hard to differentiate between a real particle and a virtual particle. The only real (nontechnical, observable) difference is that one is observable. But, I suppose each has their way of looking at this, and they are equivalent so it doesn't matter. Just pointing out this isn't the only way to look at it.
Quantum mechanically, sure, but we're talking about QFT here. Time is to be considered.
I meant QFT in terms of quantum mechanically (obviously, else virtual particles make no sense at all). Minus the odd instantaneous transfer of momenta associated with virtual quanta, I'm just not sure I see the difference. And in fact, if you want to call them different, I think explaining bumps in invariant mass spectra &other resonances become very complicated--what are you exciting if not a virtual particle? The dynamic Casimir Effect seems even more odd without this appeal to the vacuum. Not saying you can't disregard virtual particles (hell, QFT can be formulated without particles at all), but I think they're fairly intuitive and not so distinct from normal particles (same coupling, etc). Same Landau pole, just not the on-shellness of observable particles. But hey, agree to disagree I suppose (I've been in too many arguments on these pedantic points which can go on indefinitely :P).
>a virtual particle isn't a particle
profmattstrassler.com
Guys, could you also please explain to me why small black holes evaporate faster than large ones?
Here is the short version.
Its all IMAGINE THIS,now IMAGINE THAT
How can a virtual particle just "vanish" when its annihilation partner isn't there anymore? Shouldn't it also gain "true" mass as it falls in for the same reason?
the virtual pair borrows 2 units of energy from the BH's gravity field when it forms. Only 1 unit is recovered from the one falling in.
the volume of a sphere is given by
(4/3)∗π∗r(4/3)∗π∗r
the surface area is given by
4∗π∗r24∗π∗r2
while in euclidean space the relation between the two is fixed, as soon as you curve space you get a disparity and the proportions change with growing mass towards the volume increasing faster than the surface area.
For instance a black hole's outer circumference may be x, finding the diameter seems trivial as it is given by
C/π=dC/π=d
but when the space within the sphere is not flat then this does not hold true, the diameter d will always be greater than this, the steeper the curvature, the greater the difference because there is more and more space contained within the bounds of the sphere.
This is why lighter black holes evaporate faster since the relation between volume and surface area is different from heavier black holes.
or to put it simply:A smaller sphere has a larger surface area to volume ratio. The amount of evaporation is proportional to the surface area.
So black holes radiate the same stuff, regardless of what went into it? Even if it were made of antimatter, or was a kugelblitz?
They're created in pairs and nearly always annihilate as pairs, when one or both exists for "long enough" then they're called "real particles" instead, and some kind of energy is either tied up or liberated or both in the form of a fundamental interaction or chemical reaction.
Yes.
>negative mass particle
>being gravitationally attracted to a black hole
lol
correct.
Huh. And the contents are randomly matter and antimatter in equal portion? So if you collided regular matter into a micro black hole, it would immediately burst into matter, antimatter and radiation? Conservation of something or other seems off...
Shouldn't we be calling them "black suns?"
They are merely condensed suns, even if they were giant compared with ours.
see
>Shouldn't we be calling them "black suns?"
Fusion is not occurring within them, so that description wouldn't be accurate.
Would a sun so ancient that all fuel is spent and fusion stops still be called a sun?
Black hole sun
Won't you come
And wash away the rain
Black hole sun…
>virtual particles
fucking kek you Copenhagen retards will believe anything
>Would a sun so ancient that all fuel is spent and fusion stops still be called a sun?
dead star.
And what's the case against virtual particles, pray tell?
Is that a fucking kamehameha? Black holes are 2000x cooler now wtf
A star, but not a sun? I'll buy that.
>A star, but not a sun? I'll buy that.
IT could be either, really.
Sun is just what we call OUR star.
Oh right, forgot that wasn't a technical term.
But I suppose technically no one is going to be calling a dead star anything, as they should be showing up some time after life can conceivably continue existing. I can't seem to find the numbers on that though.
what exactly are you trying to figure out?
Whether stars start being dead before or after none of the other stars being useful anymore.
I already briefly explained that some take this convention. The problem I have is that normal particles aren't all that "normal." If they have a large enough decay width, they're usually very difficult to interpret as nice, neat excitations anyway. What people don't understand is that it isn't some easy sorting of particle vs nor particle. There's a huge spectrum involved. Sure, the top quark is a particle, but is the bound state of toponium? Again, I get the pedantic differences (and that you can decompose the actual particle nature into other vacuum properties), but there's very little key difference for me. I already stated that there's a fair amount of debate on this (and the final answer isn't very important), but more than anything, it's a little exhausting when people on sci constantly try to correct me on things they know nothing about (when I have a phd in particle physics).
NO NO NO NO NO NO. This is what happens with CLASSICAL GR only, and we know that this isn't true. It's a major theoretical issue with a multitude of proposed solutions (see "firewall paradox" for more info), but there's a fundamental thing called unitarity that would be violated if black holes were truly classical. Somewhere inside the black hole, the information about the quantum numbers is stored, and this will influence it's radiation as it evaporates.
what kind of pairs are we talking about e+e-?
I thought they can't appear in vacuum, or i'm missing something and mechanism is different.
>Negative mass
You what?
nvm black hole can act as a nuclei
You lost me at explain. How's something have negative mass? Mass is like energy so wouldn't negative energy just be energy. Or I get it. I have negative energy and.what energy I do have or get.cancels and I have no energy. I'm tired.
But the mass change of the black hole is difficult to measure next to a photon that happens to leave it's twin inside. I left my twin inside a black hole once. He must be doing well.
Huh. I knew a little bit about the information thing, didn't realize it's further implications. Well at least my question touches on something important. That's satisfying in a sense.
>Somewhere inside the black hole
or... somewhere in its gravity field are remnants of the tiny distortions that were caused by stuff falling in (hairy BH hypothesis)
There are no particles.
Everything is fields and fields are not particles.
Stephen Hawking and Albert Einstein are fools.
do you do any work theoretical or otherwise? Theres a korean dr. Cheung on my campus that does some neat stuff. I need ask him some qs
Then what field are black holes an excitement of?
All of them?
What do you think of my interprentation of a particle in pic?
Yeah, I'm a high energy or "particle" theorist. I work a lot with dark matter, the evolution of the early universe (often called the thermal history), and trying to find out why the particles we have are what they are.
BTW is your "korean dr. Cheung" Yeuk-Kwan in China? Regardless, you should totally go talk to him as soon as you get the chance. He'll blow your mind in minutes. Always talk to profs when you have the chance!
Yeah, thanks for the correction--I was sloppy. In fact, it CAN'T be inside the black hole (well, at least it isn't well-defined to be entirely contained inside of its surface. Of course, I always get confused as what constitutes the surface of a black hole (I'm not a big fan of giving love to removable singularities)
If I'm interpreting it correctly, then it's ruled out. To be clear: my interpretation is that you're representing the size of the particle at current temperatures by the circles on the right, and then you evolve the coupling constants and masses and eventually determine that they are all the same particle at the grand unification scale? You're probably misinterpreting the idea that those particles could sit inside the same representation; that doesn't mean they're the same particle. TL;DR your view violates every gauge symmetry known to the universe--cute picture, but not physics. Back to the drawing board!
PS--bet you didn't think that your usual troll post that frequents every forum was actually in some way relevant here (or to particles) :P
Can you prove that my drawing is false?
Without using if x is true, then y must also be true so what you said is false
Wtf is negative mass
Not a theo. Phys. student but I've seen enough episodes of Through the Wormhole with Morgan Freeman that I could basically have a PhD in this shit so you can trust me when I tell you that you're a fucking idiot
Also my hero/real dad Neil DeGracias Tyson told me that when they made the Titanic movie they got the stars wrong so basically youre all fucking retarded
What's really going to cook your noodle is the question of how the black hole creates the magnetic field needed to focus the Kamehameha.
lol, meme science confirmed. anyone who believes this unobservable, unconfirmable fake science is an idiot.
I got the graph from a website talking about CERN. Ofcourse it is about particles
If this is actually from CERN, it is one of the worst graphics I've ever seen and is fairly unclear. The part without the circles is fine (that's in every textbook on particle physics), but the rest is an unclear eyesore.
>Whether stars start being dead before or after none of the other stars being useful anymore.
A star is "Dead" when fusion is no longer occurring within it.
Granted, that is an extended process taking millions / billions of years, but... yeah.