Event Horizons and Black Holes - Sixty Symbols

[@1KevinsFamousChili1]

A paper that short with no equations would have been ignored if it wasn't Stephen Hawking. I am interested to see where this goes

[@MathAndComputers]

...and single-author usually either means that 1) it wasn't meant as an actual paper, but more of just an informal comment, 2) colleagues thought it was a great, novel idea, and didn't want to take credit for something they didn't contribute to, 3) colleagues didn't want to be associated with it because it'd be embarrassing, or 4) colleagues didn't care about it, because it doesn't really mean anything. My money's on some combination in this case.

[@Samuel-ni7vv]

Feels more like Hawking has, in his own head, claimed ownership of black holes and then proceeds to disprove other scientists works regarding black holes with statements constructed of merely a fraction of the scientific evidence compared to the works he is trying to disprove.

[@David-ud9ju]

A lot of theoretical physics papers have single authors.

[@TheJanitorIsIn]

Nowhere, apparently lol

[@kadircelikYT]

@@TheJanitorIsIn how come?

[@blanktester]

Claiming it now, Future Null Infinity is the name of my new heavy metal band.

[@nazgullinux6601]

Sounds too close to Meshuggah's song called, "Future Breed Machine" for my tastes.

[@sth128]

This stuff is too heavy for me.

[@dkevans]

And infinitely dense.

[@luisdanielmesa]

Physics Trolling 101: first say: "...therefore Black Holes evaporate" then say: "There are no black holes to begin with..." xD

[@WisemanTimes]

This is a perfect example of science evolving. Its a criticism those who dont believe in science says all the time.. "but the theories change and some are even wrong that have been proven so why take any of it seriously." I say to those people... Stephen Hawking is showing what learning is... taking previous theories and refining them... its not that they are wrong.. although some are... its just that either the science wasnt far enough or our tech wasnt good enough to test. Science is about learning and growing a better understanding and not just taking one theory and basing everything on it. I am positive one day Einstein will be proven wrong.. we just arent at the level to do it yet!

[@x19Julius92x]

Please Brady, PLEASE render your videos more loud because your videos are the most quiet of my subscriptions and i am bothered turning the speakers up every time just for your videos :) Thanks :)

[@pygmypieman9988]

please sixty symbols make a video on magnetic motors. I am sick of finding videos on these 'law defying' devices. I must say though I don't fully understand the physics and would love for you to make one so that you could educate myself and others on this topic plus shut-up some ignorant people who think others have made things which defy the laws of thermodynamics and create infinite energy.

[@kobil316SH]

Pygmy Pie Man that's thunderf00ts job

[@stargazer7644]

Umm, aren't most electric motors magnetic?

[@dewinthemorning]

No black holes anymore??? That's great news! No, actually, 6:01, "You've got to redefine what is a black hole." Phew, black holes are saved. They just probably don't have an event horizon, just an apparent horizon! I sort of hope that Hawking doesn't prove that there are no black holes, we are so used to hearing about them.

[@Aryanne_v2]

Black Holes fascinate me like nothing else does. They are so amazingly terrifying, and the physic behind them are incredible.

[@johnlewis6430]

What physics?

[@alexneo1722]

John Lewis Don't even

[@00bean00]

Perhaps he means the physics _in front of_ them, or a time perspective. :p

[@markanderson1088]

RIP Dr. Hawking. You have been an inspiration to many generations on many levels. Thank you.

[@ghuegel]

Something this difficult and confusing is sure to get a massive response from the physics crank community.

[@MrZerausogaitnas]

This is the first sixty symbols video I don't understand.

[@Cold_Ham_on_Rye]

It's sad. I love your numberphile videos... because I can understand almost all of them... sixty symbols on the other hand... I never understand a single thing

[@b4ux1t3-tech]

I applaud you for not disagreeing with them simply because you don't understand them. That's what a lot of people do, so it's refreshing to see people who accept that they just don't understand. That said, I strongly encourage you to read Hawking's paper. It has a lot of ridiculously complicated points, but in general is pretty comprehensible to the layman, myself included.

[@peter_castle]

read more math (friendly advice) you gonna get smarter

[@blackflan]

Don't worry, it happened to me xD I began following brady's channels from numberphile.. and didn't really liked sixty symbols at that moment, but you'll get it eventually ;) they're great, even if my passion is math, I really love physics, specially particle psysics.

[@skroot7975]

"Grey hole" doesn't sound as exciting. :L

[@KlousePlayer]

SkrootNissu Yoctomind I think that I've realized one of the big problems I have.. Read "Glory hole" for the first 2 times.

[@erictaylor5462]

+nyemi productions Glory holes are exciting for an entirely different reason. Now don't go sticing body parts into a black hole, though I'd advise against glory holes as well.

[@MathAndComputers]

One thing I've never seen explained (not that I've looked extensively) is why, if photons couldn't escape an event horizon of a black hole, are there gigantic jets of X-ray photons escaping all the time out from the poles? Does the event horizon just not apply there, and if so, why? Why are these huge jets not usually even mentioned in the same discussions as those talking about energy loss of a black hole? Are they just the remnants of things that almost but didn't quite fall in?

[@Sbence92]

The jets are believed to be created by the Blandford-Znajek process, which basically needs an ergoshpere and an accretion disk. These regions are outside of the event horizon, so the black hole plays by the rules.

[@Mernom]

Those are created by the conditions of the accretion disk. It's essentially a super massive particle accelerator.

[@Maikkeru]

more videos please. Professor Ed Copeland video number 3, The suspense is killing me.

[@jpheitman]

"There is no such thing as black holes" is a bit presumptuous. It would be more accurate to say, "Black holes don't work the way we thought they did."

[@stargazer7644]

Well, if they're not black, and they're not holes, then it would seem to me to be more presumptuous to continue calling them black holes.

[@jmdj530]

Don't you mean Future Null -1/12th ?

[@maciejukasiewicz7661]

Wait a second there. Assuming that there is this apparent horizon from which light can eventually escape, does that mean that all that light is "compressed" and stored in the singularity, awaiting release? Please bear in mind I'm no physicist; just a layman trying to understand what could possibly be a pretty significant paradigm shift.

[@qpid8110]

He had an elegant solution but the end of the paper was too small for him to write it down. 😱

[@infinummjb]

I do not understand. If black holes evaporate by swallowing particle/antiparticle from particle-antiparticle pair and those are entangled with each other than all information that escapes a black hole is just the opposite of what came in, hence no information is really lost. Than again if on average black hole swallows as much particles as it does antiparticles from particle-antiparticle pair than no net mass change should occur, so the black hole should not really evaporate. BTW since we do not know and can not know by definition what goes on behind the horizon than how come anyone can assume there exists such a thing as a singularity? Can it be more probable that a black hole is not empty but is rather more like a perfectly entangled quantum-liquid, a bit like liquid helium but with higher density? If we then replace the horizon with the apparent horizon than that would make the black hole more like a dense black star.

[@Jenny_Digital]

When I was very very young I imagined that in the end the whole universe would ultimately get sucked into a black hole. Somehow they've lost much of their menace in recent times. Fascinating all the same.

[@severedize]

Could the black holes be creating the dark matter by evaporating light? I don't understand my question.

[@philbuglass4857]

Just recently discovered this channel, and I am enjoying myself binge-watching the videos. Why is it, though, that they all seem to start in the middle? Sometimes, literally in mid-sentence! Very disconcerting... This one actually stops mid-sentence too!

[@justinchan1045]

Brady, when are you uploading the third extended interview

[@monev44]

Regarding hawking radiation. why do does the anti-partical of the pair supposed to fall in more then the normal partical? would the odds be 50-50? thereby they would average each other out and have a net 0 effect on the total mass of the black hole?

[@StillElias]

can you look at a black hole from the side or behind it? or would it just look the same?

[@brodericksiz625]

What do you mean by "side"? How can a spheroidal object have sides?

[@tj12711]

+Blue Wolf It's kinda like asking if you can look at Earth from "the side or behind it". It's an ellipsoid, so there isn't a set definition for sides just like ellipses, circles, and spheres do not have sides

[@StillElias]

***** I understand normally in pictures or videos it's shown as a hole in space like the opening of a tunnel. That's why I asked

[@Kavukamari]

+Blue Wolf I think it's more of an artistic rendition rather than something physical. I think it's to help people understand that things fall in and it's really hard to get out but I think a lot of the time, you'll see a disc of stuff around the black hole that you can view from a flat edge, and that's because the black hole spins, and the tidal forces pull everything into a flat plane around it, like our solar system or a galaxy does to the stuff orbiting around it

[@yeetspageet5679]

Apparently interstellars black hole (a film) has the most realistic looking black hole

[@panjshir07]

very well done guys I enjoyed the video. I seen to many publications that total got Hawking's paper all wrong

[@vegardpig8634]

why does none of these videos have any maths in them? i just want to learn the confusing maths

[@Ternadil]

because these videos are ment to explain things in basic level to people. you can learn the math elsewhere

[@yaweimar]

They'd just throw tons of symbols at their viewers which have absolutely no meaning to them I think it's better to explain things in words if you want real science go to Wikipedia or study physics

[@vinitchauhan973]

vegard pig first you need to understand the ideas and principles, then move on to the maths.

[@RiaRadioFMHD773]

Where logic fails me is: How can photons (which have no mass) even be affected by the gravitational attraction of a black hole? I know that the escape velocity exceeds c in a region (event horizon) surrounding one, but I just assumed the black hole would act like a lens only distorting & bending light around it.

[@remavas5470]

Gravity is not a force, it's curvature in spacetime and Gravity affects everything with momentum, which light certainly has.

[@stephentrigg374]

+RiaRadioFMHD773 Photons do have mass (all energy has mass). They just don't have a rest-mass (you couldn't have a photon at rest). If you prefer to think about it in terms of space-time curvature, there is an amount of curvature (of your gravitational lens) where light forms a loop or spiral - that's a black hole.

[@AlexOjideagu2]

+Remavas that is not totally true. Gravity is thought to have a force carrier the Graviton

[@BallermusicProd]

+ojideagu from a particle physics point of view yes, but speaking of general relativity no... just a quick hypothesis: maybe physicist were't able to come up with a theory that properly describes gravity and the other forces as a whole because they are looking in the wrong direction and think of gravity as a force... but i have not yet understood enough of this to make an intelligent ramble about it

[@_BLACKSTAR_]

it is not the photon itself that is being acted upon by the gravitaional force of the black hole, but rather the spacetime itself that the photon is in.Its like a photon is a person in a raft, & the water is the spacetime, & the falls are the event horizon of the black hole.Even though the raft can paddle through the water at a very high rate of speed, the gravity of the falls pulls the water itself even faster than the raft can paddle once you go over the falls, the water itself is falling faster than the raft can paddle.IE once the space the photon is in crosses the event horizon, the space itself is moving toward the singularity faster than the speed of light, & the photon moving at C cant exceed the rate at which the space is being drawn toward the singularity.

[@DudokX]

"I call it a Hawking Chamber."

[@Novenae_CCG]

What about, as oppsoed to Black Hole (in which everything falls and doesn't get out), when name it a Black Gutter. Things that fall into it jsut sort of sit there.

[@DudokX]

***** D'oh!

[@HenchPenguin]

Would love to see a video on Cherenkov radiation! :]

[@picknikbasket]

Fantastic to get this update and commentary from two eminent physicists so soon after Hawking's publication. Great stuff Brady!

[@Infloresence]

Now I'm completely confused. Keep up the good work.

[@PhysicsPolice]

12:24 "It's difficult for him to write down anything" What nonsense! He wrote this two page paper, you think he can't write down a couple lines of equations?

[@ACDCRULESALL]

so if i understand sort of correctly. when the apparent horizon collapses or whatever the correct word would be i dont know, all of the light that was in it escapes.. so would that be a spot of extreme light for a period of time? when all the light escapes im assume it escapes at once, so would that not be be extraordinarily bright?

[@theatheistpaladin]

So what... gray-holes now?

[@kharnakcrux2650]

Russian math prof once told us.... "it's advisable to know the answer before you start to solve it"

[@TimmacTR]

So......what happens to Black Holes after they "evaporate"? Is there nothing left? I would suggest that intuitively at one point, just like a chemical reaction reaching an equilibrium, there wouldn't be enough energy to propulse matter outside of the black hole and that at that point the object would stabilize.. Anyone has an idea?

[@iammaxhailme]

He has a truly marvelous resolution to get rid of the firewalls, but it's too long to fit in the margin.

[@ccon9610]

Haha. Let's hope this isn't Mr. Hawking's "Last Theorem." :D

[@Arycke]

It was D: R.I.P. Hawking :'(

[@vinitchauhan2928]

iammaxhailme quantize gravity

[@PersimmonHurmo]

@@Arycke No.

[@Arycke]

@@PersimmonHurmo Yes.

[@sazarod]

"Future Null Infinity" is a great name for a prog metal band

[@randomnamegbji]

I don't understand how he means that a black hole would realise the information. What would cause this apparent horizon to dissapear?

[@sp00l]

Go read the paper =]

[@wmilberry]

While they don't clearly say, I would assume evaporation. As a black hole evaporates there comes a point where it would have insufficient mass to maintain an event horizon. I think what happens at that point has been a question, but this new view avoids that quandary.

[@ShaneClough]

I think (and I could be wrong) that the formation of a black hole should somewhat mirror the evaporation. So because of this if there is no event horizon at the black holes formation (which there isn't), then there will not be one at the end of its evaporation, therefore sometime between when the event horizon is created and the black holes evaporation, there is a time when the event horizon dissipates. The information is released as hawking radiation.

[@MultiMaikimaik]

How do we know that the antiparticle is always the one falling in? Shouldn't it be 50/50? So the hole doesnt shrink or grow right?

[@davecrupel2817]

R.I.P. Dr. Steven Hawking. May you finally find what you had been searching for, for your time in this reality.

[@davidm.johnston8994]

Seriously there's one thing I don't get : I thought the second law of thermodynamics was probabilistic, that it is only more probable for entropy to increase in a system, but then I keep hearing that black wholes loosing information violates this law. To me it's not a violation since even if the probability for entropy to increase over times is greater than for it to decrease, it's expected that it can also decrease at times. Can someone lighten me on this issue?

[@bloody_albatross]

I feel there is something lost in editing. Why does the black hole evaporate? Because the particle that falls in is anti matter. That bit seems to be lost.

[@BenRuijl]

The singularity arrow should be pointed at the event horizon, not at the middle of the black hole. At the event horizon you divide by zero.

[@BlueEyesWhiteTeddy]

I have a question. Is there a fixed percentage of the radius of the "event" or "apparent" horizon, at which point the escape velocity is bigger than the speed of light, where light cannot orbit the singularity?

[@Matt113113]

+Blue Eyes White Teddy The equation that deals with the compression of an object into a black hole is called the Schwartzchild equation. Basically, the bigger the mass of an object, the larger it's radius can be and still have surface gravity high enough to not let light escape. The Schartzchild radius for Earth is 8 mm, while the one for the sun is about 3 km. If any object becomes compressed to it's Schwartzchild radius, it will become a black hole.

[@BlueEyesWhiteTeddy]

Matt113113 i didn't ask that.. ?

[@Matt113113]

***** Oh, I see. Well the percentage is 0, the event horizon defines where photon can no longer escape

[@BlueEyesWhiteTeddy]

Matt113113 Right, but seeing as the escape velocity can never be the same as the orbit velocity the percentage cannot be 0% or 100% depending on how you start counting.

[@salottin]

What happens with the matter when the black holes disappear? o.O

[@TheMohawkNinja]

I'm going to need to read that paper. So, is a black hole going to only be defined by its singularity?

[@thermotronica]

Whoever finds out quantum gravity 1st, ill buy them a donut

[@lammatt]

Hawkings can BS a page or two and still manages to get it published in good journals while many hardworking and insightful people out there struggle to even get their papers accepted by any journal.

[@TeslaRifle]

Presumably they would decay into something like a neutron star over the course of their life if they are losing mass to radiation emission? At some point they would lose enough mass before evaporating to become visible again?

[@IamGrimalkin]

Under the old model- no. The event horizon shrinks, but the matter inside the black hole remains at infinite density, so is still within the schwarzschild radius until the black hole fully evaporates.

[@Falcrist]

It occurs to me that everyone talking about this issue is discussing only black holes. However, black holes aren't the only place where we find an event horizon. What do these ideas do to the edge of the observable universe?

[@camdenfitzgerald2557]

So in QM, entangled atoms/ particles, don't send information. They just mirror each other and is described often as spooky at a distance. So please explain how the information of these said partials can be lost if there is no information in the first place.

[@JustOneJJ]

For some reason when I saw videos thumbnail I thought that Brady was going interview Hawking. Well even without him video is awesome as always

[@ctpaja]

Can you do a video about how black holes evaporate?

[@DoctorScarlet]

This. I had no idea that they could even do such a thing.

[@dankkiller1]

I never hear of a spinning black hole. would a black hole break the law of conservation of angular momentum?

[@innyve89]

I'm confused about the whole losing information thing. The other particle just gets turned into energy or its just there and we can't see it. And eventually be emitted as just energy. What says it disappears completely?

[@sidewaysfcs0718]

Vincent Russell the information about it;'s partner is lost via Hawking radiation, the radiation is indiscriminate about what goes inside, that violates conservation of information, a big no no. Leonard Susskind's solution was that the information is smeared across the event horizon, from our point of view, any object that gets too close to the black hole gets literally plastered on the event horizon and thermalized, hense the firewall.

[@yeswellfrombrittany6907]

+Vincent Russell No, it IS "created" at the same time its 'antitwin' is "created" inside the "space" of the black hole. That's the shocking thing. On our side, there's more energy and on the other side there's more antienergy somehow.

[@lastsilhouette85]

So the virtual particle going into the black hole must have negative mass then, right? I mean, what other physical method could retain energy conservation AND have a particle come into existence while another one takes mass away from a black hole? If not, what am I not understanding here? I mean, physically, how else could a particle entering the black hole take AWAY mass?

[@SandroAerogen]

I didn't understand what 'future null infinity' means and when I search for it on google all the explanations are filled with difficult technical terms that make it even harder to understand.

[@williamcolt1073]

curiously if this is true; I would think by shifting the polarity of the light coming out of the black hole we should the be able to identify where the black holes apparent horizon begins.

[@qTnD42hR]

So, all in all, at one point in time something that looks like an event horizon might exist, as you can observe no light coming through a region of space, but eventually that "black hole" will evaporate and that light will come out? If I understood correctly, it's more like a stasis hole then, at least for light.

[@Alex-bw6yd]

I'm so glad to hear disagreement about the Firewall hypothesis. For me it is absolutely the least likely, and least interesting hypothesis put forward on what happens at the Event Horizon.

[@PhilAMurray]

So what causes an apparent horizon to disappear. Does that happen when the gravity well evaporates?

[@Zoltan1251]

wow i am amazed about how many people dont really know what black hole is...... it is just very very dense object, determined by its mass, it do not "suck" anything....... you can have black hole mass of the sun in the centre of solar system and nothing really would happen, except no light coming out of it

[@markmayonnaise1163]

You could say that the people whom you describe are also very dense objects.

[@vinitchauhan973]

Zoltan1251 incorrect, solar mass blackholes will exist for a very brief amount of time, initial this is true

[@cimmik]

What makes the apparent horizon disappear?

[@cocas1000]

Copelandia, Galerina, Gymnopilus, Inocybe, Mycena, Panaeolus, Pholiotina, Pluteus, and Psilocybe. About 40 species are found in the genus Psilocybe. Psilocybe cubensis is the most common psilocybin mushroom in subtropical areas and the black market.

[@videotrash]

Very interesting topic. Though I think the explanations were a little bit muddled and vague in this one... probably has to do with the complex nature of the subject. I just didn't get the jump from at one time talking about entangled particles, at the edge of the black hole and then suddenly talking about human observers walzing into the black hole- I had the impression you mixed metaphors there. And I didn't get what the antidesitter-space is about at all.

[@MephistoRolling]

this is the first time i have heard that black holes evaporate, i thought they just grew more intense over time.

[@stargazer7644]

Black holes emit Hawking radiation and they shrink - His big contribution. But it takes a while.

[@LeeMcKay]

It kinda makes sense when you think about it. Time could stretch or compact within the "black-hole" and the observer couldn't tell the difference , they just go through the journey's rotation life cycle. We could be in a black-hole ( but that's thinking way out side the box ) and for us it's normal

[@WhatIsGod]

If we live in a multidimensional universe with the force carriers of gravity slipping between universes why is there any issues with the firewall paradox?

[@Loopyrad]

Could it be that as the black hole evaporates the event horizon shrinks and reveals light that was previously at the edge of the event horizon trying to escape?

[@_BLACKSTAR_]

its not the photon that is acted upon by the gravity, but the space itself, & no, once the space crosses the event horizon everything in it, including all photons is now headed directly toward the singularity faster than the speed of light

[@walrusman8691]

I find this very interesting. Thank you for this video!!!

[@voxlvalyx]

I enjoyed the video and I respect Steven Hawking, but that thumbnail was a bad idea.

[@Dunning-Krugereffect]

***** That's the idea.

[@TheVino3]

+Ailuri Why was the thumbnail a bad idea? Does stephen hawkings face offend you?

[@BloodyHand29]

+Ailuri You should probably go on tumblr and complain there.

[@voxlvalyx]

BloodyHand29 tumblr is for idiots. I meant the thumbnail seems like it's making fun of him.

[@VitriolicDiatribe]

"Tumblr is for idiots" that's his point. Tumblr is for people who get offended over nothing. Do some research on how Hawking feels about his own representation.

[@isodoublet]

The idea that equations are missing from his paper is somewhat valid but misplaced. In his solution, there simply can't be event horizons. It's a very simple topological argument, and unless you're working at the level of mathematical physics no equations should be required there. I would like to see the math to his assertion that this periodically identified AdS metric is the one that interpolates between formation and evaporation, however. It's a different question to focus on: instead of "do event horizons exist in this model?" we ask "is this the model that should describe real black holes?" Although Hawking didn't present any calculations, there are some heuristic arguments that are suggestive. First, similar to how an observer at infinity needs an infinite amount of time to observe an object crossing the event horizon, they would also need an infinite amount of time to observe an event horizon forming in the first place. A nice treatment of this including semiclassical effects is given by some guys (including Lawrence Krauss) here: arxiv.org/abs/gr-qc/0609024 . A second reason would come from topological censorship. It would be impossible, without violating the average null energy condition, to change the topology of spacetime from one without a singularity to one with one. Now admittedly this is a much weaker argument, since topological censorship is essentially a conjecture at this point, and also it is conceivable that gravitational collapse would incur ANEC violations that would enable a singularity (and its supporting event horizon) to form, but I believe it's an interesting point. I'm a physicist but not a specialist in gravity, so take what I said with a grain of salt. But in my humble opinion the information paradox itself seems like the result of attempting to reconcile disparate descriptions from different coordinate systems, so doing away with the event horizon in this manner seems elegant. And future calculations may show it's perfectly compatible with observation.

[@travboat]

Professor Copeland looks absolutely delighted that black holes aren't eternal. See 13:30. I think it's pretty exciting, too.

[@aggeman2]

What happens to the concept of a singularity in this model where the event horizon doesn't exist? I've always thought that the singularity was the defining characteristic of a black hole.

[@lordofhatred510]

So does that mean there is naked singularity?

[@uriel69879]

to me, a black hole is something that is so dense that it lags in time, everything in it lags behind the present. It's too heavy to keep up with time.

[@PhysicsPolice]

We can still call them black holes, they just deserve a realistic description. Hawking proposes "... that black holes should be redefined as metastable bound states of the gravitational field."

[@rhodesy761uk]

How do you know there not stuck in static time.

[@XxxclarityxxX]

+Paul Rhodes ?

[@SkullTraill]

+Paul Rhodes Because you don't know the difference between 'there' and 'they're'. That's how I know.

[@irishgypsy25701]

So would this debunk the holographic universe theory? It was based partially on how information was lost or rather trapped in a black hole, right?

[@missingno3391]

Just a random question that has nothing to do with this. Would it be possible for a galaxy to have nothing in the middle but just be orbiting around the stars on the outside?

[@Scarlov87]

this makes me think about light, on "black holes" light could change it's frecuency, and behave on a very different way like an ultra violet or infra red frecuency, or just bend as a part of some kind of magnetic refraction right?, if there are super mass bodies light would escape from them slower? wich means that light may not be that intense when reaches its viewer or could change the perception of the time that certain events happen on space...

[@wrathofpain5]

If the particles that are popping in and out of existence are drawn to each other, how exactly does one of them escape the other? Even if one is inside the event horizon and the other one isn't, shouldn't the one that is outside the event horizon try to follow its 'twin' and also fall into the black hole? That makes no sense to me.

[@wrathofpain5]

I understand that much but why does it fly away if it is attracted to the other particle is what I am asking. These particles appear, collide, and disappear but since they are attracted to each other why wouldnt the other one follow its twin?

[@GameNationRDF]

They are not attracted to each other, they are entangled. One pops in the event horizon the other don't. So the one in the horizon gets pulled in while the other either escapes or orbits the black hole.

[@yeetspageet5679]

+GameNationRDF isn't one of them a particle with negative mass? Isn't this what causes the black hole to evaporate. And if so, surely there is a 50/50 chance that it will be anti/normal matter so how would the black hole evaporate at all?

[@yeetspageet5679]

+xPflegusch I thought negative energy and mass did exist? Or aren't they at least theorised to exist? And I understand that, how is the energy transferred across the event horizon / apparent horizon? From the two entangled particles.

[@yeetspageet5679]

+xPflegusch and thank you for the explanation, it's made the best sense so far

[@EUROPAMusicOfficialChannel]

I fully understand this, but I keep seeing comments from people saying that they don't get it. just pay attention to everything they say and it makes sense.

[@PaleeCML]

If nothing can escape from black holes how it is possible that they evaporates and how?

[@peterfaber9316]

Question..... Space is expanding. Gravity is countering the expansion of space. Is the event ( or aparent ) horizon the region in space where space is not expanding?

[@NekuraCa]

Is the apparent event horizon here similar to the event horizon that an observer sees when constantly accelerating towards the speed of light?

[@shamanahaboolist]

Hawking is totally onto something here. Everything we observe regarding energy and information is that it is conserved. The idea that black holes provide a source of cyclic motion and change and that information isn't lost and just radiation emitted as an end result is a theory which is much more correlative with observation and perhaps gives us insight into why the size of a black hole correlates with how many stars surround it.

[@BIT1FFY]

Why should it be that its the one with negative mass that pops into existence within the field of the black hole. Seeing as this (as it appears to me) is all about the chance that a matter/antimatter pair of particles suddenly exist on either sides of the horizon, why should it be that more often than not its the positive mass one that escapes? Is it a "more-often-than-not" situation or is it always that positive escapes, negative gets trapped? If its all about the random creation of entangled matter/antimatter particle pairs either side of the horizon boundary, then surely it should maintain a stable system. Anyone?

[@sharpyd]

+BIT1FFY An antiparticle has opposite charge, not negative mass. Both normal and antimatter have positive mass.

[@louigi6001]

Maybe to an outside observer, just like things approaching the black hole, the event horizon persists for a long time but if you were to observe things from something gravitating around the black hole close to where the event horizon would be things would happen much quicker ... so maybe the event horizon is only present for a very short relativistic time ?

[@aaronphillips402]

Will the light that's absorbed by the black hole ball up for trillions of years inside the black hole, and then when the black hole fades will the light be suddenly released all at once? Sounds like an apparent horizon could do something like this.

[@EnragedTurkey]

So, would it be possible to stick a ship inside an Apparent Horizon and just sit inside for however many million years until it evaporates and then escape, thereby hiding inside a black hole where it cannot be detected?

[@sciencemage6283]

if its not a black hole what is it do we need a new name?

[@jimharmon9917]

It was my understanding that the event horizon is that distance at which the level of gravity there causes the escape velocity to equal the speed of light. Any closer and the escape velocity is greater than the speed of light; any farther and escape velocity is less than the speed of light. If this is true, how can there NOT be an event horizon?

[@mosab643]

What did they think would happen when a black hole evaporated away, before this paper came out?

[@sadriposting]

if someone could freeze the black hole to zero absolute, what would happen?

[@IamGrimalkin]

But don't we know that CPT symmetry doesn't fully apply because antimatter exists in the wrong quantities?