*For the particle pairs that appear next to the event horizon:* wouldn't an equal number of matter and antimatter halfs be pulled in? Why would only the antimatter get pulled in?
I second your question. As I understand virtual particles they spring out of nothing as particle and anti-particle. Some vanishingly short time later they collide, annihilate, thus returning to space the energy they borrowed to come into existence. Hawking radiation would suggest that the anti-particle is the only one that ever falls into the singularity. Really!? That's awefully lucky! I'd think that the odds were 50/50 thus balancing between radiating and growing.
It doesn't matter which particle falls into the black hole. Whether it's photons, protons or antiprotons coming from the black hole, this violates the laws of thermodynamics. So the black hole has to give up mass to let them escape.
Most of the time, they're photons, which are their own antiparticle. But other particles can be created this way too. You might want to watch this collaboration with Dr. Paul Matt Sutter to better understand them: ua-cam.com/video/Kn5PMa5xRq4/v-deo.html
Correct me if I'm wrong but seems like we still don't understand the temperature of the inside of a black hole. Because from what I understood the way we figure out the temperature is from whats being released . I believe the temperature inside a black hole is much hotter than a stars, because if you look at a flame the color is orange and the hotter it gets the color becomes white eventually now BH could be the next level.
I've got the following question, hope that it would be interesting. Suppose that there are 27 people forming 3x3x3 "cube" and they are falling into black hole. Let us consider the guy which is in the center of this cube : this guy has exactly one another guy before him, behind him, over him, under him, from the left from the right and so on. What this guy would see looking at his companions while faling into the black hole, say first entering the region where the circular orbits are unstable, then to the region where are no circular orbits and finally while crossing the event horizon? There is often repeated slogan that when one crosses the event horizon one does not notice anything special however I think that in such circumstances this is not the case. For simplicity let us assume that our black hole is not consuming any star at this moment. Could you make the video explaining such a scenario? It would be fascinating to understand what actually happens
I have many question about black hole. (1) 3:56 If black hole can gain mass when they absorb light, is it possible to create black hole from only EXTREMELY HUGE amount of light ? (2) Can I destroy or explode black hole by throwing EXTREMELY HUGE amount of charge particle to make it have EXTREMELY HIGH positive or negative total charge? (3) Can I destroy or explode black hole by throwing EXTREMELY HUGE amount of anti-matter? (4) Can EXTREMELY HUGE amount of dark energy cancel black hole's gravity and destroy(or explode) it?
1. Yes, you could make a black hole only out of light. 2. No, you can't kill a black hole with charged particles. You just make it bigger. 3. Nope, antimatter just makes it bigger. ua-cam.com/video/6zw5DuWAyco/v-deo.html 4. We don't know what dark matter is, but black holes probably eat that too.
3:00 "The larger the event horizon, the less paths there are that a photon could take" I'm having trouble understanding that part. We can think the event horizon as a sphere, right? Wouldn't a bigger sphere have the same number of perpendicular paths as a smaller one?
Hi Fraser, is it reasonable to comment that a Black Hole is a "System" which converts mass into complete energy, if so will it be logical to say that it can reverse the process too and execrate matter from raw energy too. Also can it be assumed that a black hole rips the particles off the "Weight Component" of every particle and stores them as "Weightless Energy" inside the black-hole and releases them in a blast when they evaporate. Would be really grateful if got some sort of reply from you regarding these questions .. thank you :)
Is it possible that heat/energy can't escape a black hole so it is not detectable- so it would be "cold". But if you where close enough within it's gravitational pull, you would feel/detect the heat, because you are in the stream of it towards the pull?
I find myself frequently searching on the topic of singularities in black holes. I have read many articles and watched many videos on the topic, yet none seem to go as deep into the subject as I would like. One specific point that bothers me is that assuming there is a single point of infinite density and gravity where massive amounts of matter fall into, only to disappear into the infinitesimally small point and yet retain all of the mass. If it 'disappears' from the known universe, how then does it have any mass, and then by definition, any gravity?
I dont get the "hard topic " thing here. It all make sense, was explained simply and with images. We were not killed with huge math blocks trying to prove the talk right etc. So I think it was nice. Although I was missing an estimation of how long black holes can live, for example black hole made from earths' moon vs average brown dwarf life span expectations or something :D
What is the mass (or radius) limit for an evaporating black hole to stop being black hole and fall apart? I mean, there has to be a point, where there is so little material, that the gravity of the stuff cannot hold the black hole together any longer and it is torn apart by repulsive forces of particles. Right?
Whatever may exist behind the horizon cannot come out by "repulsive forces" - there is no force capable of tearing the signularity itself apart. However small black holes will keep shrinking and radiating; at the final stages this process will be very rapid. But it is the shrinking of the horizon that drives this process.
Jason93609 Aha! So that means that once event horizont is formed, there is no way back - space is so curved that until the black hole pops out of existence entirely, there is still event horizont... wow. That's quite mindbending. Thank you!
3:08 you say that energy can not be created nor destroyed: *yet you taught me that red shift from the expansion of the universe causes a loss/destruction of energy.*
You made me wonder (strictly hypotheticly) if the the loss of energy due to red shift has something to do with the space time's gain of dark energy. Then again im quite sure if this would be the case it would be explored and activly researhced by now.
A universe that dynamically changes size (i.e. has a time-dependent scale factor) is not expected to conserve energy in general. But even then you can account for all energy contributions.
Energy can be handled as potential difference, and potential difference disperse over distance (space) and so conservation of energy can be violated this way which also implies that time symmetry violated as well which still seems fine on large scale where expansion takes over gravity. So this can explain the time evolution of the universe from the BB to the heat death while on smaller scales like particles we can have our time symmetry and energy conservation. But this is all well understood, the question is how is it that the dark energy does not dispers the same way through space but keeps its density (thats why it takes over gravity on vast distances) Answering my firts question though which wasn't rly thought through ( you can tell), that there is most likely a correlation between the two thing but its almost definatelly not a causation.
I have a new question that might be interesting. How cold are neutron stars at their core? My (amateur) understanding is that they are very dense at the core, so it seems to me that there should be very little wiggle room and therefore very little in the way of temperature. Surface temperatures of newly formed neutron stars would be an exception, but my question can be stated as follows: _"are old neutron stars colder than the space around them?"_ My gut feeling on this is "yes", but I haven't looked into it for myself.
The temperature inside a newly formed neutron star is from around 10^11 to 10^12 K. However, the huge number of neutrinos it emits carry away so much energy that the temperature falls within a few years around to 10^6 K. You're welcome. 👌 Actually I thought yours was a very interesting question I had to look for the answer myself. 👍
L Galicki Thanks for that. Astronomy is not my field, but it's a fascinating subject. I imagined them being a bit toasty at the start and then cooling off quickly (millions of years). The figure you gave is warmer than I imagined, so I'll try to steer clear of them as best as I can. :)
Black hole may seem very cold, but seeing as they cant emit anything when not feeding(except hawking radiation, perhaps), couldnt it actually be scorching hot at the singularity?
Theoretically what happens to a black hole when is dies in this blast you mention? Could it allow for new stars/planets to form from the particles that are released?
It's a final blast of photons, so nothing new could form from that.
8 років тому
How can it be that those virtual particles that appear randomly everywhere and unrelated to the black holes cause a black hole to evaporate just because half of the pair falls in?
We talk about this here: ua-cam.com/video/MJb6colKwzo/v-deo.html
8 років тому
Fraser Cain Thanks for the link, but that video doesn't really explain the reasoning either. Just that it is what happens. Is it because the particle that falls into the black hole will find it's counterpart and annihilate each other, thus reducing the mass of the black hole?
Balázs Suhajda Did you see this one? ua-cam.com/video/Kn5PMa5xRq4/v-deo.html
8 років тому
For a second I thought I'd be able to relax with the comfort of a clear answer... But then the physics of virtual particles and wibbles, wabbles of fields said NO. Or as Paul put it "It's not exactly tied to the mathematics of Hawking radiation, but it's not exactly wrong either". Just going to have to accept that black hole evaporation doesn't add up for a noob like me. :)
Does anyone know if this is still the case that we haven’t found any explosions? Also, I understand how temperature is related to mass but aren’t these particles that pop into existence and causing hawking radiation based on probability? So saying a big explosion should happen? Meaning millions of pairs of particles are being created a second? If this is the case is there a higher probability of these pairs being created because there’s such a high energy density in the field due to there being a black hole?
When blackholes are feeding on other stars, do they or are they creating heavier metals/elements than what's already known? or is it only Gamma Ray/pure energy release?
They create starlike conditions in the accretion disks around them, which probably fuses heavier elements, but then the black holes eat it up. The only thing that can really escape is the energy, and individual particles.
I posit my query again, from a second video: How fast would something need to move in order to pass into a black hole without experiencing speghettification? Is something like that even feasible?
The more massive the black hole, the smoother the event horizon. A stellar mass black hole would tear you apart almost instantly, while you could fly into a supermassive black hole for days and not even realize you've crossed the event horizon.
+Fraser Cain Oh, cool! I wasn't aware they were THAT powerful! So it is pretty much impossible to pass through the Event Horizon without being turned into a pasta dish. Thank you for the reply!
ive read something about a month ago that a bunch of astronomers from around the world were starting a project that would take the first picture of a black hole thats at the center of our galaxy
Is there a captain here that can explain me this : I don't understand how the black hole can lose energy. Because when the pair of particle/antiparticle that was created in the vacuum of space is separed, the blackhole will lose the mass of the particle that goes away but will gain the mass of the other particle that was in the event horizon...
I was thinking this was going to be about the temperature of the mass (or whatever bizarre stuff it has become) inside the event horizon. As mass gets compressed, it gets hotter, and the mass in the core of the black hole has been compressed to a ridiculous extreme, so it should be incredibly hot, like the universe a tiny fraction of a second after the big bang.
Because it is so compressed there are no space for particles to move around. Temperature "is the agitation of molecules". So the core of a black hole is probably much closer to 0 K.
That's why I am dissatisfied with this video. I hoped that you will say something about singularity, not about event horizon. Maybe the video will be better if you will explain in 30-60 seconds why temperature no longer makes sense inside the event horizon, for amateurs like me.
Wouldn't that be the temperature of its radiation and not the temperature of the black hole itself? If the temperature you are talking about is related to free paths leading away from the event horizon and if this temperature is a function of mass it would have to be the temperature of the Hawking radiation and not the black hole itself. Or did I miss something?
That's right. When you measure the "temperature" of a black hole, you're really just measuring the temperature of the event horizon. We don't know what the temperature of the singularity is, because no heat can escape.
My head just exploded. I can't fathom anything here. I thought that I understood about a black hole but now I have no idea. You really confused me with black holes with the mass of Ceres, that doesn't make sense to me at all. If (visualising space-time as the rubber sheet) gravity distorts space-time to form a well is a black hole like a bottomless pit?
We need to clarify that the Bekenstein Hawking temperature is what observers far away from the BH's event horizon would measure. Observers hovering above the event horizon will see a much higher temperature since they're on a highly accelerated trajectory. Free-falling observers will see something completely different (I want to say that they won't see any radiation but I haven't actually worked it out so I'm not sure right now).
What would be the difference between a black hole explosion / blast and a supernova? How would we decipher that an explosion in space was from a primordial black hole instead of a star?
going back in time to the beginning of the galaxy prior to sgr*a going nova and creating the milky way, how big do you think it could have been as a primordial star?
I know you guys all know this, but from a _distance_ it may appear as though the BH is radiating, but really, it's _absorbing_ half a pair. It doesn't appear to be _loosing_ anything at all. Just _gaining _*_half_*. But, if they're entangled, that would mean Einstein-Rosen Bridge for *every* pair! Wormholes coming off like hair from all around the BH.
We've done 3 episodes on Hawking energy. Here's part 1: ua-cam.com/video/MJb6colKwzo/v-deo.html Here's part 2: ua-cam.com/video/Kn5PMa5xRq4/v-deo.html And here's part 3: ua-cam.com/video/LRtvGABJC2Q/v-deo.html
Could black holes just be a 5th state of matter? You have solids which melt into liquids, heat is up it turns into a gas but compress so much you get plasma, and the entire weight of a star is on a single point. So could that just make the 5th state of matter? It could explain why things disappear to us with them since the gravity crushes it into the state of matter of a black hole. But that’s a theory as most of these since we can’t know for sure. Only make guesses
Hi Fraser, I keep hearing that inside the event horizon the escape velocity is higher than light speed. Great, but isn't escape velocity only relevant to objects without engines? You can leave Earth having any speed as long as the engines of your rocket are powerful enough, right? Do the laws of physics forbid the existence of an engine powerful enough to escape an event horizon?
It is impossible to create an engine shooting things into the black hole with greater force than the GeForce’s pulling on the rest of the ship. So the only way to increase the force of the engine beyond the gforces of the black hole would be to have Yoda in the ship.
Does a blackhole gains mass when one of those particle-antiparticle pairs (the whole pair) falls into it before self-annihilating? If so, is there a size at which a blackhole gains more mass that way than it loses with Hawking radiation?
No, if both go in, then nothing happens. The black hole doesn't have to pay any price. Remember, they're not actually particles, they're wibbly wobbly fields. ua-cam.com/video/Kn5PMa5xRq4/v-deo.html
Could the spin of the black hole be what allows radiation to escape? Something similar to the P-factor of an aircraft propeller and how it imparts energy to the aircraft body - a smaller particle than a photon of light would require less energy to escape the event horizon.
am i stupid when i assumed you measured the temperature of a black hole in its singularity (even though you probably can't). measuring the event horizon of the black hole just seems like measuring the vacuum of its surroundings. plz correct me so i know why this is wrong
Hmm, I'll do another video at some point. Like, "why don't black hole singularities make any sense?" Then we can talk about why temperature, time, physics, everything gets all mushed up inside the singularity.
Personally, not a big fan of a lot of Hawking's theories but this was pretty interesting. But it's always bugged me what the temperatures would look like around black holes, in the event horizon, and the singularity. Heat is created by energy, and black holes are pure energy being compressed to unfathomable measurements. So naturally I'd imagine the singularity would be just as immeasurably hot with a little heat escaping due to some "evaporation" if it isn't currently taking in substantial amounts of energy at that point in time. As for the event horizon, I would imagine it's extremely hot too assuming there is a detectable temperature. Gravity, itself, is energy or a force that pushes energy. That and the fact that you move exponentially faster towards the singularity (as speed is directly related to energy) would further suggest that it only gets hotter the closer you are to the singularity. But whatever, not that I think any of this truly changes anything even if we have the answer, I suppose it's fun to think about.
As I understand it in a *very simplistic* way is that if matter/energy inside a black hole is packed in tight enough, it wouldn't be able to "wiggle around" as much. "Heat" is caused by particles wiggling and vibrating, bumping each-other. the more mass, the less "wiggle room". Eventually something can become so dense (super-massive black holes) the material that makes it up is almost not bumping around inside itself at all. I say almost, because eventually it will be able to radiate energy, but that is a lonnnggggg way off. Am I wrong? I am not a scientist. :)
Nothing can jump out of the event horizon because, in a sense, behind the BH horizon space itself is 'moving' inwards faster than light. So there is no way to move outwards behind the horizon. Even if you think about quantum mechanics you'd refer to uncertainty in position / momentum, not average motion outwards, which would be the quantum analogue. So the only such case worth considering would be entangled pairs that are released at the vicinity of the event horizon. But I digress. The point is that black holes need to have a finite nonzero temperature or they would be destroying heat content. So applying notions of thermodynamics necessitates that black holes will emit thermal radiation. That's what Bekenstein managed to show. Hawking also showed that *and* provided an explanation for why it happens from a 'microscopic' point of view. When you are far away from the black hole you will see the Hawking-Bekenstein temperature. But if you hover above the event horizon you would be seeing a far grater temperature, since you would have to accelerate outwards to prevent falling in. So it's analogous to the Unruh effect (described shortly after the Bekenstein-Hawking entropy).
The definition of Absolute Zero, is the lowest temperature that can be reached where no further energy can be extracted. Because of quantum mechanics, the particles are still moving a little bit.
hard to believe that black holes can even become so small as to get "hot". Sice the formation of the hole requires a certain sized star or certain minimum amount of mass to begin with I would've assumed that this amount of mass is required to keep the black hole in this black hole state. Has anyone ever proposed the idea that a black hole that shed too much of its mass just becomes a visible (neutron) star again or even explodes? Is it fact that a black hole is a fixed object that can only die by shedding all its mass as hawking radiation or is there a possibility that a black hole is just an extreme state of matter like a Bose-Einstein-Condensate which could collapse back into regular/visible matter once some conditions stop being met?
the tidal forces close to a black hole would tear the fallen apart, atom by atom. from the fallen atoms perspective when they cross the event horizon they reach the speed of light, so they experience no time. from a distant observer it would happen in the infinate future. so...never
Fraser Cain but people must agree on causality, and if they never see you cross the event horizon, but could still observe your effect on light, even though they may need super sensitive equipment to pick up low energy light, then both observers would have to agree that the black hole evaporates before you can cross the event horizon
Fraser Cain thanks, that's basically exactly what I was saying. But I do have one question, is there a difference between mass stick just outside the horizon and the mass that used to be outside the horizon, bit the blank home grew so now it's inside the horizon? Would time dialation make it go backwards in time? Including time dialation, what does matter do inside the event horizon?
But what about the temperature at or near the core of a Black Hole? Certainly all that crushing near-infinite mass would be generating some kind of heat. Ad in the fact there is no way for that heat to quickly dissipate or escape, and there should be a runaway greenhouse effect in there the likes of which boggle the mind!
Could we consider the background temperature to drop down when galaxies have expanded a lot due to dark energy? What could be the consequences when a black hole is isolated in a single galaxy, would it absorb the galaxy until it evaporates?
This discussion of virtual pairs forming at the event horizon led me to ask what is the width of the boundary itself. Turns out, the event horizon boundary is infinitely thin. In other words, apparently, the event horizon around a black hole is a surface consisting of a sphere of points. A point is a mathematical concept, but it has no real existence. Wouldn't that mean that an event horizon exists only mathematically, but has no meaning in reality? Then doesn't that mean that "reality" is just a mathematical concept?
I have an astronomy question unrelated to Black Holes. Can the mass of super-earths and mini-neptunes overlap (IE are the least massive mini-neptunes less massive than the most massive super-earths)? If so, has anyone looked into why this could be?
Talk about what it would look like if you could set up a lawn chair on the surface of a black hole and look out to watch the universe from that perspective(Edit: with and without gravitational distortion). It would look like a 4th of July fireworks finale, right? Everything comes into existence and explodes in seconds....billions of years passing each minute? If you sat on that black hole since its beginning looking at your watch the whole time, the black hole would only appear to be minutes old, even after the last star burnt out?
in other words, if you fell into a black hole, you would freeze in an instant. So you would never feel the pull of the black hole because you would already be dead.
This answered a question, but not my question. My question is: what, if anything, does general relativity and/quantum physics, say about conditions, in local proper time, about the interior of a black hole? It's actally a tough question, as there is no working theory of quantum gravity.
I am doing a project on this subject, and i just searched up on google "how cold is a black hole?" and it had a script of writing that is EXACLTY the same as his script in 3:22 XD
Fraser Cain so pretty unlikely hahaha. If I rephrase it to: Would we ever be able to extract energy from out space-time? i.e. use a wormhole to a star and extract it's energy?
Could black holes be extremely cold spots in space and the laws of thermodynamics say that cold tries to absorb heat and those cold spots are absorbing any heat they come in contact with and it goes down the black hole to who knows where the black hole is anti star the exact opposite of a star
Taking the temperatures of black holes is pretty damn hard to do, For starters, if you use a thermometer to measure the black hole's temperature and you put the thermometer on to or next to the event horizon, it will fall into the black hole, never to be seen or heard from again. If the black hole you're taking the temperatures of is surrounded by an accretion disk, the disk would likely interfere with the measurements you were attempting to make. Then there would be the task of actually FINDING a black hole in the first place, as black holes are invisible because their gravity is too strong for even light to get out of the black hole. The only visible indicater that would give away the presence of a black hole would be the gravitational lensing effect around the event horizon. These are the reasons why it's mighty hard to take the temperatures of black holes
There are ways to take the temperature of something without actually putting your thermometer into it. You can just measure the temperature of the radiation coming from it.
+Fraser Cain well, if you think of a photon as a marble falling through the deep hole, in principle, the marble has no way to get out of the hole by its own. Either the gravity gets inverted or the hole destroyed, otherwise the marble would stay there forever. If the hole was theoretical it could be infinitely deep. But the black hole "folds" in a kind of a fourth dimension that isn't one of the three we're used to doesn't it?
Why would we expect a supermassive black hole to explode once it's no longer massive enough to maintain itself as a black hole? Wouldn't gravity continue to hold it together like a quark star or something, just teetering on the edge of gravitational re-collapse?
I was wondering Ok if this is a holographic universe then is it possible that we are on the event horizon or past that of a black hole ? This could explain the expanding universe or dark matter as a still feeding black hole. The speed of light is unbreakable because then we could leave the black hole were already in. Also, quantum entanglement at large scales and wormholes could be explained as not faster than light transfer of information or bending of the entirety of space but just jumping one grove of information to another on the 2-d plane we exist on. Leonard Susskind has shown that information isn't lost inside a black hole as Hawkings previously speculated. Just an uneducated thought. I love this channel and enjoy every video.
Cluster Reduction i was thinking the same thing hence all the filter theories of us even traveling in universe its simple math in relation to fermi, distance time space and our current understanding of the universe
you aren't just feeling the infrared... you are feeling every photon that your skin will absorb. That includes visible light photons and lots of others that aren't "infrared"
One thing is absorption, and the other is feeling what's been absorbed. Is our skin capable of feeling radio, microwave, visible light, UV, X-ray or gamma rays?
i wonder if hawking ever watches youtube videos of other people explaining his theories and chuckles to himself at our feeble attempts to understand.
I'm sure he's laughing right now.
Simon we all have a little troll in us 😈
Yoshiko Akiyama damn man, you beat me to that comment
If you like this stuff you'll love (do da math)
@@Simon-hb9rf i dont think hes watched much youtube lately
Actually, you do a fantastic job explaining it Fraser. Thank you and love the vid.
Phew. :-) Thanks!
So, could you tell me if there are currently any evaporating black holes or will only evaporate once the background temperature is lower?
Yeah, they won't start evaporating until the Universe is much colder.
*For the particle pairs that appear next to the event horizon:*
wouldn't an equal number of matter and antimatter halfs be pulled in?
Why would only the antimatter get pulled in?
I don't think the pairs mentioned here are matter and antimatter. I think they're some sort of photon?
I dont think you are correct.
I second your question. As I understand virtual particles they spring out of nothing as particle and anti-particle. Some vanishingly short time later they collide, annihilate, thus returning to space the energy they borrowed to come into existence. Hawking radiation would suggest that the anti-particle is the only one that ever falls into the singularity. Really!? That's awefully lucky! I'd think that the odds were 50/50 thus balancing between radiating and growing.
It doesn't matter which particle falls into the black hole. Whether it's photons, protons or antiprotons coming from the black hole, this violates the laws of thermodynamics. So the black hole has to give up mass to let them escape.
Most of the time, they're photons, which are their own antiparticle. But other particles can be created this way too. You might want to watch this collaboration with Dr. Paul Matt Sutter to better understand them: ua-cam.com/video/Kn5PMa5xRq4/v-deo.html
Correct me if I'm wrong but seems like we still don't understand the temperature of the inside of a black hole.
Because from what I understood the way we figure out the temperature is from whats being released . I believe the temperature inside a black hole is much hotter than a stars, because if you look at a flame the color is orange and the hotter it gets the color becomes white eventually now BH could be the next level.
Appropriate colour shirt and T-shirt ...!
Yup. :-)
I've got the following question, hope that it would be interesting. Suppose that there are 27 people forming 3x3x3 "cube" and they are falling into black hole. Let us consider the guy which is in the center of this cube : this guy has exactly one another guy before him, behind him, over him, under him, from the left from the right and so on. What this guy would see looking at his companions while faling into the black hole, say first entering the region where the circular orbits are unstable, then to the region where are no circular orbits and finally while crossing the event horizon? There is often repeated slogan that when one crosses the event horizon one does not notice anything special however I think that in such circumstances this is not the case. For simplicity let us assume that our black hole is not consuming any star at this moment. Could you make the video explaining such a scenario? It would be fascinating to understand what actually happens
I have many question about black hole.
(1) 3:56 If black hole can gain mass when they absorb light, is it possible to create black hole from only EXTREMELY HUGE amount of light ?
(2) Can I destroy or explode black hole by throwing EXTREMELY HUGE amount of charge particle to make it have EXTREMELY HIGH positive or negative total charge?
(3) Can I destroy or explode black hole by throwing EXTREMELY HUGE amount of anti-matter?
(4) Can EXTREMELY HUGE amount of dark energy cancel black hole's gravity and destroy(or explode) it?
1. Yes, you could make a black hole only out of light.
2. No, you can't kill a black hole with charged particles. You just make it bigger.
3. Nope, antimatter just makes it bigger. ua-cam.com/video/6zw5DuWAyco/v-deo.html
4. We don't know what dark matter is, but black holes probably eat that too.
3:00 "The larger the event horizon, the less paths there are that a photon could take"
I'm having trouble understanding that part. We can think the event horizon as a sphere, right? Wouldn't a bigger sphere have the same number of perpendicular paths as a smaller one?
I wanna know this as well
Hi Fraser, is it reasonable to comment that a Black Hole is a "System" which converts mass into complete energy, if so will it be logical to say that it can reverse the process too and execrate matter from raw energy too. Also can it be assumed that a black hole rips the particles off the "Weight Component" of every particle and stores them as "Weightless Energy" inside the black-hole and releases them in a blast when they evaporate. Would be really grateful if got some sort of reply from you regarding these questions .. thank you :)
Is it possible that heat/energy can't escape a black hole so it is not detectable- so it would be "cold". But if you where close enough within it's gravitational pull, you would feel/detect the heat, because you are in the stream of it towards the pull?
I find myself frequently searching on the topic of singularities in black holes. I have read many articles and watched many videos on the topic, yet none seem to go as deep into the subject as I would like. One specific point that bothers me is that assuming there is a single point of infinite density and gravity where massive amounts of matter fall into, only to disappear into the infinitesimally small point and yet retain all of the mass. If it 'disappears' from the known universe, how then does it have any mass, and then by definition, any gravity?
Did you ever see this video? We don't really know what's inside the event horizon.
ua-cam.com/video/FjP8u4O1uQU/v-deo.html
I like these hard topics. Keep it up!
Thanks!
I dont get the "hard topic " thing here. It all make sense, was explained simply and with images. We were not killed with huge math blocks trying to prove the talk right etc. So I think it was nice. Although I was missing an estimation of how long black holes can live, for example black hole made from earths' moon vs average brown dwarf life span expectations or something :D
he just probably meant very interesting and non-trivial topics, calm down!
I meant that indeed. Thanks for clarifying.
:D
I LOVE THIS CHANNEL! YOU GUYS NEED MORE SUBS!
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@Dylan T Energy isn't lost in redshift it's spread as space expands and becomes less concentrated, so we observe less energetic, longer wavelengths.
'Blast of Primordial Black holes.'
2020: Lemme check my schedule.
What is the mass (or radius) limit for an evaporating black hole to stop being black hole and fall apart? I mean, there has to be a point, where there is so little material, that the gravity of the stuff cannot hold the black hole together any longer and it is torn apart by repulsive forces of particles. Right?
Whatever may exist behind the horizon cannot come out by "repulsive forces" - there is no force capable of tearing the signularity itself apart.
However small black holes will keep shrinking and radiating; at the final stages this process will be very rapid. But it is the shrinking of the horizon that drives this process.
Jason93609 Aha! So that means that once event horizont is formed, there is no way back - space is so curved that until the black hole pops out of existence entirely, there is still event horizont... wow. That's quite mindbending. Thank you!
It's not the gravity, it's the evaporation that makes it disappear in the end.
3:08 you say that energy can not be created nor destroyed:
*yet you taught me that red shift from the expansion of the universe causes a loss/destruction of energy.*
It infinitely approaches zero, but never reaches zero. Heat death is the inability of particles to interact.
You made me wonder (strictly hypotheticly) if the the loss of energy due to red shift has something to do with the space time's gain of dark energy. Then again im quite sure if this would be the case it would be explored and activly researhced by now.
So what is your conclusion ?
A universe that dynamically changes size (i.e. has a time-dependent scale factor) is not expected to conserve energy in general.
But even then you can account for all energy contributions.
Energy can be handled as potential difference, and potential difference disperse over distance (space) and so conservation of energy can be violated this way which also implies that time symmetry violated as well which still seems fine on large scale where expansion takes over gravity. So this can explain the time evolution of the universe from the BB to the heat death while on smaller scales like particles we can have our time symmetry and energy conservation. But this is all well understood, the question is how is it that the dark energy does not dispers the same way through space but keeps its density (thats why it takes over gravity on vast distances) Answering my firts question though which wasn't rly thought through ( you can tell), that there is most likely a correlation between the two thing but its almost definatelly not a causation.
I have a new question that might be interesting. How cold are neutron stars at their core? My (amateur) understanding is that they are very dense at the core, so it seems to me that there should be very little wiggle room and therefore very little in the way of temperature. Surface temperatures of newly formed neutron stars would be an exception, but my question can be stated as follows: _"are old neutron stars colder than the space around them?"_ My gut feeling on this is "yes", but I haven't looked into it for myself.
The temperature inside a newly formed neutron star is from around 10^11 to 10^12 K. However, the huge number of neutrinos it emits carry away so much energy that the temperature falls within a few years around to 10^6 K.
You're welcome. 👌
Actually I thought yours was a very interesting question I had to look for the answer myself. 👍
L Galicki Thanks for that. Astronomy is not my field, but it's a fascinating subject. I imagined them being a bit toasty at the start and then cooling off quickly (millions of years). The figure you gave is warmer than I imagined, so I'll try to steer clear of them as best as I can. :)
it will be hard to steer clear of that heat when you're as hot as a neutron star ;) I'm really sorry lol I will slap myself for you now
Dale Docker Your calculation didn't take my icy cold stare into account. Haha.
Haha well the heat would definitely melt that but right now I feel the intensity of the icy stare lol
Black hole may seem very cold, but seeing as they cant emit anything when not feeding(except hawking radiation, perhaps), couldnt it actually be scorching hot at the singularity?
We don't know what happens once you get inside the event horizon.
but what tempreture is past the horizon? considering how dense black holes are I suppose 10^infinity
We have no idea. That region is beyond our ability to measure... for now.
Absolutely brilliant explanation, rivaling Isaac Arthur himself!
Theoretically what happens to a black hole when is dies in this blast you mention? Could it allow for new stars/planets to form from the particles that are released?
It's a final blast of photons, so nothing new could form from that.
How can it be that those virtual particles that appear randomly everywhere and unrelated to the black holes cause a black hole to evaporate just because half of the pair falls in?
We talk about this here: ua-cam.com/video/MJb6colKwzo/v-deo.html
Fraser Cain Thanks for the link, but that video doesn't really explain the reasoning either. Just that it is what happens. Is it because the particle that falls into the black hole will find it's counterpart and annihilate each other, thus reducing the mass of the black hole?
Balázs Suhajda Did you see this one? ua-cam.com/video/Kn5PMa5xRq4/v-deo.html
For a second I thought I'd be able to relax with the comfort of a clear answer...
But then the physics of virtual particles and wibbles, wabbles of fields said NO. Or as Paul put it "It's not exactly tied to the mathematics of Hawking radiation, but it's not exactly wrong either". Just going to have to accept that black hole evaporation doesn't add up for a noob like me. :)
Does anyone know if this is still the case that we haven’t found any explosions? Also, I understand how temperature is related to mass but aren’t these particles that pop into existence and causing hawking radiation based on probability? So saying a big explosion should happen? Meaning millions of pairs of particles are being created a second? If this is the case is there a higher probability of these pairs being created because there’s such a high energy density in the field due to there being a black hole?
But how can you know the temperature of the core of a black hole?
Really cool video that really put black holes in a picture that i can grasp
When blackholes are feeding on other stars, do they or are they creating heavier metals/elements than what's already known? or is it only Gamma Ray/pure energy release?
They create starlike conditions in the accretion disks around them, which probably fuses heavier elements, but then the black holes eat it up. The only thing that can really escape is the energy, and individual particles.
I posit my query again, from a second video: How fast would something need to move in order to pass into a black hole without experiencing speghettification? Is something like that even feasible?
The more massive the black hole, the smoother the event horizon. A stellar mass black hole would tear you apart almost instantly, while you could fly into a supermassive black hole for days and not even realize you've crossed the event horizon.
+Fraser Cain Oh, cool! I wasn't aware they were THAT powerful! So it is pretty much impossible to pass through the Event Horizon without being turned into a pasta dish. Thank you for the reply!
ive read something about a month ago that a bunch of astronomers from around the world were starting a project that would take the first picture of a black hole thats at the center of our galaxy
Yup, this is the Event Horizon Telescope. we'll do an episode on it eventually.
Just wondering
if there is a limit to how cold an object can be (absolute zero), is there a limit to how hot an object can be?
Maybe? We'll be doing an episode on this shortly. But there's not a clearly defined limit in physics like there is with Absolute Zero.
+Fraser Cain Ahh I see. Thank you for your reply :)
Thank you for explaining in an easy way
Here in 2020
Thanks, I'm glad you enjoyed it.
Is there a captain here that can explain me this :
I don't understand how the black hole can lose energy. Because when the pair of particle/antiparticle that was created in the vacuum of space is separed, the blackhole will lose the mass of the particle that goes away but will gain the mass of the other particle that was in the event horizon...
It has to be exactly at the event horizon, which is part of the black hole, therefore inside albeit just barely.
I think the mass is not of the particle that got away, but of the energy required to extract a particle-antiparticle pair out of the vacuum.
+TiagoTiago thank you :)
+Grégoire Kubler (Gvreergo) No problem :)
The extreme density would create lots of heat though right?
That's what I would imagine. I don't know how they got the "cold" idea.
That black hole just absorbs its own heat.
I have a question, Can a black hole die or do they Stay around forever?
Black holes evaporate over vast periods of time. Here's a video: ua-cam.com/video/MJb6colKwzo/v-deo.html
Amazing explanation. Thank you.
I was thinking this was going to be about the temperature of the mass (or whatever bizarre stuff it has become) inside the event horizon. As mass gets compressed, it gets hotter, and the mass in the core of the black hole has been compressed to a ridiculous extreme, so it should be incredibly hot, like the universe a tiny fraction of a second after the big bang.
Because it is so compressed there are no space for particles to move around. Temperature "is the agitation of molecules". So the core of a black hole is probably much closer to 0 K.
Once you get inside the event horizon, the concept of "temperature" no longer makes sense.
That's why I am dissatisfied with this video. I hoped that you will say something about singularity, not about event horizon. Maybe the video will be better if you will explain in 30-60 seconds why temperature no longer makes sense inside the event horizon, for amateurs like me.
Wouldn't that be the temperature of its radiation and not the temperature of the black hole itself? If the temperature you are talking about is related to free paths leading away from the event horizon and if this temperature is a function of mass it would have to be the temperature of the Hawking radiation and not the black hole itself. Or did I miss something?
That's right. When you measure the "temperature" of a black hole, you're really just measuring the temperature of the event horizon. We don't know what the temperature of the singularity is, because no heat can escape.
Why do we use underpants to measure temperature?
Profit?
Because it's thermal underwear. :)
To not let the black hole pop out on winter.
Like, what kind of underpants you'll need for different temperatures?
So if my Kelvin Klein underpants are 1.0 Kelvin they are far hotter than a solar mass black hole at 0.00000006? I think I'm getting good at science.
My head just exploded. I can't fathom anything here. I thought that I understood about a black hole but now I have no idea. You really confused me with black holes with the mass of Ceres, that doesn't make sense to me at all. If (visualising space-time as the rubber sheet) gravity distorts space-time to form a well is a black hole like a bottomless pit?
where on the black hole do the virtual particles escape
We need to clarify that the Bekenstein Hawking temperature is what observers far away from the BH's event horizon would measure.
Observers hovering above the event horizon will see a much higher temperature since they're on a highly accelerated trajectory.
Free-falling observers will see something completely different (I want to say that they won't see any radiation but I haven't actually worked it out so I'm not sure right now).
Thanks!
Would an exploding black hole produce heavy elements like a super nova? Even more so? Or is it just a bunch of radiation?
Black holes can't explode. They evaporate, and then at the very old it's a flash of gamma ray radiation. No actual particles.
Mind. Bent. Well Done, Fraser!
Also, Well Done Commentators! These threads are some of the most civil and intelligent on YT!
Glad to bend it. :-)
What would be the difference between a black hole explosion / blast and a supernova? How would we decipher that an explosion in space was from a primordial black hole instead of a star?
Yes, the final blast from a primordial black hole would give off a very specific energy signature, like a special kind of supernova.
If the partials just pop into existence l. Wouldnt those particles have to be from the material thats in the blackhole.
This virtual particles are appearing all the time, it's just when they happen close to a black hole that things get strange.
Nice explanation
going back in time to the beginning of the galaxy prior to sgr*a going nova and creating the milky way, how big do you think it could have been as a primordial star?
I know you guys all know this, but from a _distance_ it may appear as though the BH is radiating, but really, it's _absorbing_ half a pair. It doesn't appear to be _loosing_ anything at all. Just _gaining _*_half_*. But, if they're entangled, that would mean Einstein-Rosen Bridge for *every* pair! Wormholes coming off like hair from all around the BH.
Hi Fraser, I'm a fan of your videos! I have one question for you: could you explain me how the mechanism of the Hawking Radiation work?
We've done 3 episodes on Hawking energy.
Here's part 1: ua-cam.com/video/MJb6colKwzo/v-deo.html
Here's part 2: ua-cam.com/video/Kn5PMa5xRq4/v-deo.html
And here's part 3: ua-cam.com/video/LRtvGABJC2Q/v-deo.html
Fraser Cain Thank you very much!!! You're the number one!
Could black holes just be a 5th state of matter? You have solids which melt into liquids, heat is up it turns into a gas but compress so much you get plasma, and the entire weight of a star is on a single point. So could that just make the 5th state of matter? It could explain why things disappear to us with them since the gravity crushes it into the state of matter of a black hole. But that’s a theory as most of these since we can’t know for sure. Only make guesses
does a black shrink forever or does it stop at some point?
Here's a video for you: ua-cam.com/video/FjP8u4O1uQU/v-deo.html
Hi Fraser, I keep hearing that inside the event horizon the escape velocity is higher than light speed. Great, but isn't escape velocity only relevant to objects without engines? You can leave Earth having any speed as long as the engines of your rocket are powerful enough, right? Do the laws of physics forbid the existence of an engine powerful enough to escape an event horizon?
Maybe a dimensional drive engine...whenever we make those, or they tell us that they have made them lol.
It is impossible to create an engine shooting things into the black hole with greater force than the GeForce’s pulling on the rest of the ship.
So the only way to increase the force of the engine beyond the gforces of the black hole would be to have Yoda in the ship.
Does a blackhole gains mass when one of those particle-antiparticle pairs (the whole pair) falls into it before self-annihilating? If so, is there a size at which a blackhole gains more mass that way than it loses with Hawking radiation?
No, if both go in, then nothing happens. The black hole doesn't have to pay any price. Remember, they're not actually particles, they're wibbly wobbly fields. ua-cam.com/video/Kn5PMa5xRq4/v-deo.html
Don't those oscillations have mass?
Considering the deficit of observational technology and facilities we have it's no surprise no primordial black hole deaths have been observed.
More telescopes = more better.
Could the spin of the black hole be what allows radiation to escape? Something similar to the P-factor of an aircraft propeller and how it imparts energy to the aircraft body - a smaller particle than a photon of light would require less energy to escape the event horizon.
But this might also happen that even heat is not able to escape the event horizon and hence it "looks cold" but its actually not
am i stupid when i assumed you measured the temperature of a black hole in its singularity (even though you probably can't). measuring the event horizon of the black hole just seems like measuring the vacuum of its surroundings.
plz correct me so i know why this is wrong
Once you're inside the event horizon, the concept of temperature doesn't make sense any more.
thanks Fraser! btw, love the videos! :)
Fraser. do you know somewhere I could read about why it doesn't make sense? :)
Hmm, I'll do another video at some point. Like, "why don't black hole singularities make any sense?" Then we can talk about why temperature, time, physics, everything gets all mushed up inside the singularity.
+Fraser Cain thanks! :)
Personally, not a big fan of a lot of Hawking's theories but this was pretty interesting. But it's always bugged me what the temperatures would look like around black holes, in the event horizon, and the singularity. Heat is created by energy, and black holes are pure energy being compressed to unfathomable measurements. So naturally I'd imagine the singularity would be just as immeasurably hot with a little heat escaping due to some "evaporation" if it isn't currently taking in substantial amounts of energy at that point in time.
As for the event horizon, I would imagine it's extremely hot too assuming there is a detectable temperature. Gravity, itself, is energy or a force that pushes energy. That and the fact that you move exponentially faster towards the singularity (as speed is directly related to energy) would further suggest that it only gets hotter the closer you are to the singularity.
But whatever, not that I think any of this truly changes anything even if we have the answer, I suppose it's fun to think about.
As I understand it in a *very simplistic* way is that if matter/energy inside a black hole is packed in tight enough, it wouldn't be able to "wiggle around" as much. "Heat" is caused by particles wiggling and vibrating, bumping each-other. the more mass, the less "wiggle room". Eventually something can become so dense (super-massive black holes) the material that makes it up is almost not bumping around inside itself at all. I say almost, because eventually it will be able to radiate energy, but that is a lonnnggggg way off. Am I wrong? I am not a scientist. :)
Nothing can jump out of the event horizon because, in a sense, behind the BH horizon space itself is 'moving' inwards faster than light. So there is no way to move outwards behind the horizon. Even if you think about quantum mechanics you'd refer to uncertainty in position / momentum, not average motion outwards, which would be the quantum analogue. So the only such case worth considering would be entangled pairs that are released at the vicinity of the event horizon. But I digress.
The point is that black holes need to have a finite nonzero temperature or they would be destroying heat content. So applying notions of thermodynamics necessitates that black holes will emit thermal radiation. That's what Bekenstein managed to show. Hawking also showed that *and* provided an explanation for why it happens from a 'microscopic' point of view.
When you are far away from the black hole you will see the Hawking-Bekenstein temperature. But if you hover above the event horizon you would be seeing a far grater temperature, since you would have to accelerate outwards to prevent falling in. So it's analogous to the Unruh effect (described shortly after the Bekenstein-Hawking entropy).
Leonard Susskind is the man he won the black hole war.
exploding black holes!? the universe sounds like a relatively unstable place to be, anything we can do?
Not really, you just need to wait an incomprehensible amount of time.
If the temperature is near absolute zero, can the virtual particle that is escaping even move?
Even particles at absolute zero are still moving a little.
how can it be absolute zero if they are till moving?
The definition of Absolute Zero, is the lowest temperature that can be reached where no further energy can be extracted. Because of quantum mechanics, the particles are still moving a little bit.
If somebody could figure out a way to release all the energy inside a supermassive black hole all at once. How far would it explode?
If you converted the Milky Way's supermassive black hole into pure energy via e=mc2, you'd get 7.327176×10^53 joules. That's a lot.
That energy dissipates by an inverse square relationship to distance, so even though there's a lot of energy, the energy felt far away is small
If they absorb all the energy and mass that gets near. How can they be close to absolute zero? Where does the heat go? Shouldn’t they be super hot?
The heat can't escape the black hole. All the heat they absorb just gets turned into more black hole.
Is it possible that SRB's are primordial black hole evaporation events?
Mind=blown. I didn't know what a quasar was. Thanks Fraser!
We did a whole video just on quasars, if you're interested: ua-cam.com/video/fThGKOgSo5I/v-deo.html
I'll watch it immediately. Thanks Fraser.
Good vid!
Thanks!
Black holes are so cold that if Ralphie put his tongue on one, he would never have gotten it off.
I cringe just thinking about that scene.
1.4x10 to the -14 kelvin and a solar mass black hole may have a mass of 0.00000006 kelvin
Or
3:30
Thank me anytime
4:00
Too
Great, spoiler alert.
hard to believe that black holes can even become so small as to get "hot". Sice the formation of the hole requires a certain sized star or certain minimum amount of mass to begin with I would've assumed that this amount of mass is required to keep the black hole in this black hole state. Has anyone ever proposed the idea that a black hole that shed too much of its mass just becomes a visible (neutron) star again or even explodes?
Is it fact that a black hole is a fixed object that can only die by shedding all its mass as hawking radiation or is there a possibility that a black hole is just an extreme state of matter like a Bose-Einstein-Condensate which could collapse back into regular/visible matter once some conditions stop being met?
it's it possible to fall into a black whole? wouldn't time dialation make it impossible?
the tidal forces close to a black hole would tear the fallen apart, atom by atom. from the fallen atoms perspective when they cross the event horizon they reach the speed of light, so they experience no time. from a distant observer it would happen in the infinate future. so...never
If you're falling into a black hole, you experience it in real time. But for people outside, it looks like you slow down when you get to the surface.
Fraser Cain but people must agree on causality, and if they never see you cross the event horizon, but could still observe your effect on light, even though they may need super sensitive equipment to pick up low energy light, then both observers would have to agree that the black hole evaporates before you can cross the event horizon
Samuel Owens You're talking about the information paradox. Watch this: ua-cam.com/video/vzQT74nNGME/v-deo.html
Fraser Cain thanks, that's basically exactly what I was saying. But I do have one question, is there a difference between mass stick just outside the horizon and the mass that used to be outside the horizon, bit the blank home grew so now it's inside the horizon? Would time dialation make it go backwards in time? Including time dialation, what does matter do inside the event horizon?
But what about the temperature at or near the core of a Black Hole? Certainly all that crushing near-infinite mass would be generating some kind of heat. Ad in the fact there is no way for that heat to quickly dissipate or escape, and there should be a runaway greenhouse effect in there the likes of which boggle the mind!
Nope, all that energy just gets absorbed.
When you feel the heat radiating from a toast fireplace.. XD
What is the absolute high of temperature?
Where exactly do these virtual particles even come from?
Awesome as always. On an unrelated matter - anyone notice his doggelganger in episode one of Stranger Things?
Hah, a few people have been telling me that. :-) I loved Stranger Things.
what kind of stuff is inside the event horizon?
We don't know, it's beyond our reach.
Could we consider the background temperature to drop down when galaxies have expanded a lot due to dark energy? What could be the consequences when a black hole is isolated in a single galaxy, would it absorb the galaxy until it evaporates?
No a black hole won't necessarily absorb the entire galaxy. We talked about this here: ua-cam.com/video/qRJ5Ddf2WQE/v-deo.html
This discussion of virtual pairs forming at the event horizon led me to ask what is the width of the boundary itself. Turns out, the event horizon boundary is infinitely thin. In other words, apparently, the event horizon around a black hole is a surface consisting of a sphere of points. A point is a mathematical concept, but it has no real existence. Wouldn't that mean that an event horizon exists only mathematically, but has no meaning in reality? Then doesn't that mean that "reality" is just a mathematical concept?
Wow you could be a scientist. You are so intelligent man!!!Keep up the good work!!!I want to know more!!!
수미최 What is "intelligence" other than regurgitating information from an outside source.
I've been wondering that for a while, whether black holes eventually explode. Thanks Fraser! Wonder if we'll spot one.
Astronomers are looking for them.
it would be awesome if you made a video on Hawking's no boundary principle
I'll look into that, thanks!
Topic idea: black hole farming. Civilization in a post-stellar universe
We actually talk about this at the end of this episode: ua-cam.com/video/qPZdF1Hormc/v-deo.html
+Fraser Cain Oh cool, thanks!
I have an astronomy question unrelated to Black Holes. Can the mass of super-earths and mini-neptunes overlap (IE are the least massive mini-neptunes less massive than the most massive super-earths)? If so, has anyone looked into why this could be?
Sure, you should have a smaller planet made out of gas. Astronomers are still learning all the different kinds of smaller planets around other stars.
Could you do another Uranus video? I got some more jokes I thought of :D
You got it. I think I'm going to collect them all together into a book.
Talk about what it would look like if you could set up a lawn chair on the surface of a black hole and look out to watch the universe from that perspective(Edit: with and without gravitational distortion). It would look like a 4th of July fireworks finale, right? Everything comes into existence and explodes in seconds....billions of years passing each minute? If you sat on that black hole since its beginning looking at your watch the whole time, the black hole would only appear to be minutes old, even after the last star burnt out?
in other words, if you fell into a black hole, you would freeze in an instant. So you would never feel the pull of the black hole because you would already be dead.
This answered a question, but not my question. My question is: what, if anything, does general relativity and/quantum physics, say about conditions, in local proper time, about the interior of a black hole? It's actally a tough question, as there is no working theory of quantum gravity.
I am doing a project on this subject, and i just searched up on google "how cold is a black hole?" and it had a script of writing that is EXACLTY the same as his script in 3:22 XD
I repost the script on Universe Today, is that where you saw it? I also let people repost my articles on their own sites. But I wrote it. :-)
Can we ever extract energy from a different space-time?
We would have to find other universes first.
Fraser Cain so pretty unlikely hahaha. If I rephrase it to: Would we ever be able to extract energy from out space-time? i.e. use a wormhole to a star and extract it's energy?
mind blown... again.
Happy to bend your brain.
yay another video
Yay!
Very cool!
Is electrically-charged Hawking radiation possible? Can it ever add up to a detectable change in the black hole's charge?
why the temperature of a black hole is higher when it radiates? It's counter intuitive.
Could black holes be extremely cold spots in space and the laws of thermodynamics say that cold tries to absorb heat and those cold spots are absorbing any heat they come in contact with and it goes down the black hole to who knows where the black hole is anti star the exact opposite of a star
Black holes can absorb other black holes too.
Taking the temperatures of black holes is pretty damn hard to do, For starters, if you use a thermometer to measure the black hole's temperature and you put the thermometer on to or next to the event horizon, it will fall into the black hole, never to be seen or heard from again. If the black hole you're taking the temperatures of is surrounded by an accretion disk, the disk would likely interfere with the measurements you were attempting to make. Then there would be the task of actually FINDING a black hole in the first place, as black holes are invisible because their gravity is too strong for even light to get out of the black hole. The only visible indicater that would give away the presence of a black hole would be the gravitational lensing effect around the event horizon. These are the reasons why it's mighty hard to take the temperatures of black holes
There are ways to take the temperature of something without actually putting your thermometer into it. You can just measure the temperature of the radiation coming from it.
But, isn't asking the temperature of a black hole like asking the temperature at the rim of a very deep hole?
Sort of, but the deep hole can still connect to the rim. Nothing gets out of a black hole.
+Fraser Cain well, if you think of a photon as a marble falling through the deep hole, in principle, the marble has no way to get out of the hole by its own. Either the gravity gets inverted or the hole destroyed, otherwise the marble would stay there forever. If the hole was theoretical it could be infinitely deep. But the black hole "folds" in a kind of a fourth dimension that isn't one of the three we're used to doesn't it?
Why would we expect a supermassive black hole to explode once it's no longer massive enough to maintain itself as a black hole? Wouldn't gravity continue to hold it together like a quark star or something, just teetering on the edge of gravitational re-collapse?
As it gets smaller, it just gets hotter and hotter until all its remaining mass is converted into photons.
I was wondering
Ok if this is a holographic universe then is it possible that we are on the event horizon or past that of a black hole ?
This could explain the expanding universe or dark matter as a still feeding black hole.
The speed of light is unbreakable because then we could leave the black hole were already in.
Also, quantum entanglement at large scales and wormholes could be explained as
not faster than light transfer of information or bending of the entirety of space but just jumping one grove of information to another on the 2-d plane we exist on.
Leonard Susskind has shown that information isn't lost inside a black hole as Hawkings previously speculated.
Just an uneducated thought.
I love this channel and enjoy every video.
Cluster Reduction i like the theory
Cluster Reduction i was thinking the same thing hence all the filter theories of us even traveling in universe its simple math in relation to fermi, distance time space and our current understanding of the universe
you aren't just feeling the infrared... you are feeling every photon that your skin will absorb. That includes visible light photons and lots of others that aren't "infrared"
One thing is absorption, and the other is feeling what's been absorbed. Is our skin capable of feeling radio, microwave, visible light, UV, X-ray or gamma rays?
+L Galicki yes. when absorbed it increases the energy of the atom. it gets hotter.
I feel... every photon. Even the ones tearing my DNA apart.
Don't be so sensitive!