18 Subatomic Stories: When black holes evaporate
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- čas přidán 19. 06. 2024
- Black holes seem to be timeless, lurking in the cosmos, forever eating and growing. However, astronomers believe that there is a way for black holes to shrink in size and eventually evaporate away. In episode 18 of Subatomic Stories, Fermilab’s Dr. Don Lincoln talks about Hawking radiation, the ultimate fate of black holes.
*Correction: The force numbers for objects 15,000 meters above the event horizon for a supermassive black hole were incorrect. The correct numbers are a force of 860,000 pounds for a 1 kilogram object. A one kilogram object a meter farther away from the black hole will experience a force that is only 7.3E-5 pounds lower.*
Gravitational waves explanation
www.forbes.com/sites/startswi...
Hawking radiation: Technical explanation 1
backreaction.blogspot.com/2015...
Hawking radiation: Technical explanation 2
www.scholarpedia.org/article/H...
Fermilab physics 101:
www.fnal.gov/pub/science/part...
Fermilab home page:
fnal.gov - Věda a technologie
Doctor Don Corleone over here gonna make us a lesson we can't refuse
Mr Devitt teach🙏🎤
Nice comment!
No mames 😂😂😂😂 el mejor en CZcams
Why are there so many comments about Don's name lately?
@@jullialipniitskaia VIEWER QUESTIONS
Suddenly realised it is the 18th episode. Time flies way faster when you are near Fermilab youtube channel.
Dr. Don has the most lovely disposition. I can listen to him all day.
Maybe we could do a joke section at the end of each episode? Let me start:
Why don't white bears dissolve in benzene?
Because they are polar bears.
And this would be the sound effect: czcams.com/video/GCAWmGY2lPQ/video.html
Bruh....
What if the white bear was just an albino other type of bear?
@@tbird81 well if this isn't serious enough for you then go study physics in grad school or pay for a serious course. This is just CZcams and part of Don's charm is his fun light humorous attitude.
@Bries Monis lololol boo chemists suck! Physics is *everything!*
7:51 falling trasversally into the black hole, a spaghetti will become a lasagna: #lasagnification :D
Dr Don: easing his audience on the pronunciations
Also Dr Don: gifs (7:08)
As a Pastafarian, I rejoice in the fact that everything in the universe will eventually be spaghettified.
All will serve the FSM... with meat sauce and a nice Chianti.
@@nmccw3245some sharp cheddar and a little lemon juice would be nice
My time to shine!! As Don would probably say, "the description of how 'Don' is used in Spanish is true, but there is a more accurate one". Yes, 'Don' is used as honorific BUT it is an honorific for people that doesn't have a college degree title, like Dr. for medical doctors and PhDs; Ing. for engineers, Mtro. for master degrees, etc.
When introducing a person that does have a college degree, one would NOT use 'Don' as honorific, one would say something like: Honorable Dr. Don Lincoln, or Venerable Dr. Don Lincoln, etc; The 'Don' is used as a replacement for the college degree title. If one introduces a person that doesn't have a college tittle that is when the 'Don' would be used. As a replacement for the Dr., PhD., or Ing. before the name. That's why it could have sounded a little odd.
Also, the Don as the Don Corleone, I think it's like a title in the Italian mafia, and it's a different, I don't think it's used as a replacement for the college title, one could be a doctor and still be called The Don, it's like his rank or position in the mafia.
Usage of mafia aside (which anyway concerns a limited area of Italy) generally in Italy Don is used as title for priests, usually before their first name. The priest in the village where I grew up was Don Isidoro, in Italy there’s a very popular tv series where the protagonist is a detective priest Don Matteo, etc.
if dr Lincoln was a priest in Italy he would be addressed as Don Don. 😂
@@pansepot1490 wow, detective priest!? you've piqued my interest!
@@pansepot1490 The mafia usage is in India as well (at least, in the Bollywood movies 😆)
@@MusicalRaichu czcams.com/video/Vo5_HYX_9gE/video.html
Fun fact, Don comes from Dominus, Latin for "Lord". Donna and Dame are female versions of Domina, i.e. "Lady".
Love waking up to these uploads ☕
It's the best even better than morning sex JK 😂😂😂🤣🤣🤣
Monty Python and now Wayne's World. Awesome.
Awesome? Excellent!
You are living legend sir , the discover of top quarks, Higg bosson and Hundred of research paper , I remember the video in which you were saying about that higgs bosson could be discovered in 2009 and now you had discovered it . And Thank for your reply sir ,
Ayush Joshi
Thank you very much for these videos. I've learned and enjoyed them a lot, Dr. Lincoln, Don of the Subatomic Particles (Marlon Brandon's voice). Greetings from Colombia.
My question didn't got in this one, hope it gets in the next one.
Q: how can someone call into a black hole if the time stops at the event horizon?(ofc time will run normally for the falling person ). Isn't the black hole supposed to evaporate away before the person fall in ?
Time only stops at the horizon relative to a distant observer. An infalling observer won't notice anything at the horizon, other than tidal forces. Relative to a distant observer, the black hole does evaporate before the infalling one hits the horizon, but relative to the infalling observer, he passes the horizon, and eventually gets spaghettified and then crushed at the center.
in some other sources, i read that time "freezes" for an outside observer only, due to severe time dilation, and any light reaching (from the falling body) acquires a longer wavelength, becoming red shifted, then , as the wavelength further increases, the light is no longer in the visible spectrum...In your statement, a black hole will evaporate that quickly only if it is microscopic & emits a large amount of radiation in small time (radiation temperature is inversely proportional to the black hole's mass). stellar mass monsters would take billions of years to evaporate. So , yes, a body will cross the event horizon ... hope this is helpful, buddy :) I recommend PBS spacetime channel
Answer to my question by @thedeemon:
When it gets very close to the horizon (it takes finite time to get to R+delta), total gravity of the black hole + the object makes for a new horizon that covers it, so now it’s below the new horizon.
@@ratajs Šimon to popsal nejlíp
Time is relative time only stops from the perspective of observer watching someone falling into the black hole
Time doesn't stop for the observer falling into the black hole
Its just the nature of relativity
Have we any ideas about what would happen with those remnant photons at the end of the universe? Like how they will be affected by the accelerating expansion?
The will all get stretched into ever longer wavelengths, and cluster at the horizon, eventually giving rise to Boltzmann brains as thermal and quantum fluctuations act on them over huge timescales.
They might start getting converted into mass.
Thanks for the show. Make another soon, Good Doctor.
Hi doctor Don! Thanks again for the video series! It's very insightful and funny!
Does spaghettification happen for black holes orbiting each other?
Given that black hole isn't a physical object composed of matter as we know it but rather an extreme deformation in space and time no not unless you consider the two merging event horizons during the final in-spiral as some analog of spaghettification
@@Dragrath1 what happens to the event horizon under the influence of a powerful external gravitational field?
Grateful for all the videos,
Much love from India
Even more love from America AKA The great USA 💟😍🤣😂
@@DarkLunaPath No disrespect to Americans but your country is pretty awful
@Bries Monis The cosmos truly are beautiful, but unfortunately most people don't get to worry about space and have to worry about economics
Thank you very much doctor Don!
Damn, the quantum soup of virtual particles episode is the halfway point of the series thus far? That’s gone fast. Great job in releasing these nice educational videos on interesting physics topic Don
Could you please show us your T-shirt collection?
I swear he must write the jokes print them himself for each episode. I've never seen that many science shirts in my life.
I was told temperature was randomized kinetic energy among particles, so what does it mean for the temperature of empty space to go up or down?
What you questions so confusing my guy
It means the spectrum of the Cosmic Microwave Background. Objects emit radiation that's specific to their temperature, so radiation can be "matched" to a temperature in matter, even if that matter is no longer around. The CMB was emitted by the very first atoms formed in the universe at the temperature they had at that time, which was a couple thousand degrees Kelvin iirc. Since then it has been redshifted by the expansion of the universe so now it has the spectrum that matter would emit at 2.7 Kelvin.
Temperature fluctuations and density fluctuations are one in the same. You have to assume that particles are freely moving, combining, or being destroyed at all times and that this is taking place at all points in space. Since the universe is static different fluctuations produce different temperature variances.
Nowhere in the universe is a 'true vacuum', you'll always find some particles, just not very many.
he was referring to the cosmic microwave background. It is effectively the background temperature of our universe.
Ooh, I love it when Don uploads
You guys must be close you call him by his first name! First name basis my guy you're a lucky guy to know him so personally LOL JK
No one uploads like our Don...
Hey Don! Im a new viewer and I love your channel! If the energy that gets taken from the black hole gets ejected from it, doesn't that particle then become spread across the universe, assuming our universe isn't infinite(I suppose Torus shaped-universe or something) doesn't that particle then mean that even though the black holes evaporate, other black holes will just consume that matter and grow in size as well? Another question I have is, does it matter if its a particle or an anti-particle being consumed by the black hole? Like would anti matter particles decrease the energy of a black hole or increase it? Thanks a ton if i could get an answer!
I suppose that even supermassive black holes will spaghettify you--it will just happen well inside the event horizon.
Hello Don! I am not a native English speaker but isn't GIF pronounced with a soft "G"?
Amazing videos, keep up the excellent work!
It's a point of contention that linguists and nerds alike like to gnash their teeth over. The acronym stands for Graphical Interface Format, so the creator of the standard uses the "Guh" (sounds like "gift"). However, the "gi" combination in the English language usually produces a "Juh" sound (Sounds like "JIF", as in the peanut butter brand). But, it's not the English language if it didn't have more holes and exception than a leaky ship. Also, the English language steals a lot from other languages, so good luck trying to keep any of it straight.
Long story short: "English language is a messed up language to learn, and nerd fights abound over the 'GIF|JIF' pronunciation." Good Luck!
Steve Wilhite, the person who invented the Graphics Interchange Format (GIF), pronounces it like Dr. Lincoln.
mashable.com/2013/05/21/jif-not-gifs-pronunciation-steve-wilhite/
I pronounce it GIF. PTHHHHHHHH.
Please let's not go into religious topics here :-)
I love your stuff. Thank you
Thank you for explaining this. I never could wrap my head around Hawking Radiation.
It's pronounced "GIF," not "GIF."
ROFL 🤣😂🤣🤣 oh no you didn't!!! LMFAO WTF haahaa
7:11 animated yiffs
Dr. Don Lincoln,
I watched every video you have made at\for Fermilab. Are there any more places you have videos available?
In my opinion, you are a great teacher and have much to offer. Thanks for sharing and giving out your
knowledge so freely. "You the Man."
Dr. Don has made several Excellent courses for "The Great Courses" (TheGreatCourses.com). BUT, they are Not cheap. Even "on sale", these courses cost about $50 per course (more for DVD). These courses typically consist of 24 thirty-minute lectures. You could also try "The Great Courses Plus" which is a subscription service costing $22.00 per month. All of Dr. Don's courses are available on The Great Courses Plus.
Yes, I found Dr Lincoln’s web site, and the site links back to U-tube.
Ed Rupp is correct. There are also a handful of TED videos.
drdonlincoln.com/videos
I remember sometime ago that physicists were throwing the idea that there was some kind of firewall at the event horizon of a black hole (not sure for what observer...the falling in observer maybe which would get vaporized).
Where did that firewall come from and what happened to that theory?
I don't remember where but one of the Leonard Susskind lectures on youtube he didn't agree with the firewall. If you search black hole firewall you can find it.
Large masses shrinking in size overtime, is this a weight-loss advertisement? Haven’t heard of something so wild since the hollywood cookie diet.
Hey slow down their guy I don't think you should knock the Hollywood cookie diet so fast he just probably were not eating enough cookies to properly lose the weight! I see this kind of thing all the timeif you don't eat three boxes of cookies a day you're not going to see the weight loss 😂🤣😂🤣
ugh, here we go with 'gif' pronunciations. This show has a surprising amount of linguistics for a physic-based channel ;P
He pronounced is the not ugly donkey sounding way
Question : Can you talk about pilot wave theory and and make a video about it and what are the new discoveries in this theory today
in 2020 ?
Can't believe you came to Colombia! It's such a shame a miss your event here. Question: if space-time bends, does it mean it has some kind of mechanical properties, such as a modes of vibration? What is the freq of the 1st harmonic? Is space-time a continuous?
Love your videos but gosh darn it you're such a nerd guy! I only say this because "PHYSICS IS EVERYTHING" 😂🤣😂🤣 KEEP UP THE GREAT WORK MY GUY
A man walked into a clinic
man: i'm getting really fat..i wanna reduce my weight
doctor: well... u should not interact with mr.Higgs. It will help to reduce ur mass.😎😎
good one but you should change the "man" to electron (baryons get most of their mass from strong interactions)
Dad's joke intensifies
@jumbonium &?
i prefer the tunnelling explanation, it paints a picture of why the larger the black hole the colder it is, as the bigger the black hole (larger radius) the longer the wave length(lower energy) of light needs to be so part of it can stick out above the event horizon and be emitted
@Fermilab How come photons can experience redshift (decrease in engery over time as the space they are embedded in expands) when from their perspective they don't experience time as they are lightspeed phenomenoms? Can photon energy be seen as a property of space rather than a property of the photon? Thanks for making these awesome videos, btw!
Have to say it. I want someone to look at me in the way Dr. Becky Smethurst looks at black holes. Also, what are you doing talking about black holes without doing a collaboration with her?
Hello Don, I'm a fan (from France) of your videos. I'm sure it's a lot a work to find simple understandable explanations; you make it look so pleasant. Please keep them coming. Question: How could the first gravitational wave detected (which was a binary black hole merger over a very brief timespan) emit more energy than all the stars in the observable Universe combined, given the law of energy conservation? Where did this energy come from? Thanks
the energy comes from potential and kinetic energy of the merging black holes. You start with two bodies that orbit each other at a distance and end up with a single stationary body. The energy had to go somewhere.
THANK YOU... PROFESSOR
LINCOLN...!!!
I'm going to have to call you out there Don on your answer to the "why does the amplitude fall with distance^-1?" question. Firstly, Don's 100% correct that gravitational radiation is quadrupolar; two objects falling directly towards eachother along the same axis correspond to a changing gravitational dipole, but do not emit gravitational radiation. And in static systems, the fields (gravitational, electromagnetic, or what-have-you) of dipolar systems do scale differently with radius to those of quadrupolar systems. However: radiation, but it's very nature, means the propagation of energy "to infinity". The energy in gravitational waves, just like the energy in electromagnetic waves or, for that matter, the waves on the beach or you waving your hand, scales with the square of the amplitude. However, as the waves radiate outwards, the surface area over which they are spread increases with radius, r, square. Hence, their amplitude must be proportional to 1/r, so that their energy per surface area falls as 1/r^2. This is because the area over which they are spread increases as r^2 and thus their total energy stays constant with increasing radius, i.e. it is transported to infinity. This must be the case regardless of the underlying source of the radiation, and it is also true of gravitational waves. Hence, the underlying answer to the question is simply: conservation of energy implies that the amplitude must fall as 1/r. A couple of caveats: in the particle world, radiation can be thought of as a real particle - one that obeys E^2=M^2 c^2 + p^2 c^4, as opposed to virtual particles which temporarily can violate this law - heading out of a Feynman diagram. This is equivalent, since that real particle's wave function is not exponentially attenuated, and hence it can carry its energy to infinity. Next caveat: this kind of definition ignores absorption in a medium, which is not expected or observed in gravitational waves, but does occur for e.g. light radiated from a light bulb. In that case the energy that would be transported to infinity goes to the medium.
Also: I do not like you Don encouraging people to imagine all sorts of craziness going on beneath an event horizon, and much prefer Kip Thorne's answer until we have some indication of what the form of quantum gravity looks like. Otherwise we'll keep getting very strange endings involving tesseracts to otherwise good movies.
Regarding spaghettification and SMBH: I assume you mean that there is no spaghettification outside the even horizon, but at some point inside of it, a falling object would experience it. We are just comparing a constant, c, with a wider exponential curve.
That’s very handy to save the Interstellar movie, by the way.
Yes.
@@drdon5205 thank you :)
Hey Don, love your videos. I was wondering what happens to the photons. Are they just "perpetually doing their thing" since they dont have mass and dont experience time? or do the wavelengths just get "flattened out" due to the expansion of the space they are traveling through till they are indiscernible from the ground state of the field? Sorry if this is a bit non-technical; Im not an expert in this stuff by any means.
Their wavelengths do get stretched out. That's why the CMB now looks like it's from a 2.7 K source and not a 3,000 K source, like it was when it was emitted.
Please talk about gravastars. They're almost impossible to learn about and I really can't find any good discussions about them. Thank you!
Love your videos sir ,
Just curious to know sir , if SMB doesn't do spaghettification , can it theoretically can be used as wormhole ??
Hi Don. Love your videos. With the announcement from the Borexino experiment that solar C-N-O neutrinos have finally been detected, would you be so kind as to explain why this is an important discovery and how we can know the actual source of neutrinos?
Great episode, I learned a few new things; enjoyed it. You mention stars eventually will "clump together". Will tidal forces from galactic cores cause inspiraling in ten to the gazillion years? (And, how will dark matter affect that process... not expecting an answer to this one!)
Alas, you never got one either....
thanks for the interesting videos on black holes. could you do one about neutron stars and degenerate matter?
OK, a simple explanation why amplitude falls as inverse of distance:
Power per unit of area always falls as inverse square of distance, because of conservation laws (are of sphere grows as square of distance). Also wave power is proportional to the square of its amplitude (for most types of waves: EM, sound, gravitational). Thus amplitude would fall as inverse of distance.
Exceptions to that would be if there's dispersion (or red shift) which increases the observed length of a pulse. Red shift would also decrease the full observed energy of a pulse.
I really enjoy your videos Dr. Don. keep up the good work and just know that there are many just like me who watch, but don't comment. I'm a lurker.
Oh yes a creeper I have heard the stories of the lurker or creeper I thought it was just things people made up around campfires I didn't know that it was real my goodness I need to buy me a gun for protection now LMFAO just kidding
This is the best explanation about Hawking radiation I've ever seen/heard. Thank you, Dr. Lincoln!
I found Alessandro Roussel's (ScienceClic) and Nick Lucid's (The Science Asylum) explanations to be even better:
• ScienceClic: czcams.com/video/isezfMo8kWQ/video.html
• The Science Asylum: czcams.com/video/rrUvLlrvgxQ/video.html
According to the multiple expansion, the gravitational radiation is not dipolar radiation but quadripolar radiation in case of equal masses. For pairs with different masses , it is somewhat dipolar but essentially quadripolar and reciprocaly dies out in the 3rd power of the distance (not r^2 but r^3).
Les presento a don Don. Él tiene un gran don para las bromas. Algunos nos reimos.
La gente inteligente se ríe.
Hatschi!
I have a question about black holes... several astrophysisicts have made videos about rotating black holes, and they take it as a given that the event horizon can't rotate faster than light speed. Why is that? Real 'things' can't move faster than light, but you can get apparent superluminal motion with things like shadows. So why can't the black hole spin so fast and be so big that it's event horizon is moving faster than lightspeed?
Can you post a gallery of your tee shirts, which seem to always be unique to each episode? Some I can read fully are delightful, and I would like to know where you get them, as I'd proudly wear some of them if I knew your source.
Working on it.
I wish you had started with the Unruh-related explanation of Hawking radiation first (or at least right after the popular explanation), because the popular explanation would only apply to black holes with a very high Hawking radiation temperature (thus, to very small ones).
Hey, Don! Is there an upper limit to the theoretical size of black holes?
I'm not Don, but i suppose i can give some kind of answer. Don't take serious, i'm not a physicist at all.
And here we meeting several problems which does not allow to give clean answer.
1) At first, as Black Hole gets bigger, pressure in it's center should grow. As pressure grows, properly of matter changes significantly. Actually it may be already so different that we cannot even imagine that. So let's guess that matter property does not change significantly, and it becomes simply packet tightly, very tightly, to be precise. In this case we can go some ways:
a) Quarks, leptons or whatever else makes matter itself are packed as tight that they creates one big "particle" which is the blackhole singularity itself. This makes weak force not working as we might guess, and thus there's no problem to keep it growing
b) Quarks, leptons or whatever else makes matter itself keeps their property to push each other away, and this force grows more and more the bigger pressure is. This way after reaching certain huge pressure next portion of fallen matter will cause explosion so strong, that black hole will either disappear completely or throw away significant amount of it's mass. This is possible in spinning black holes, and explosion itself, assuming it's not completely simmetrical, may create even faster spinning.
2) Singularity may not be not as small as we guessing, again, due to the inner pressure, which means the further from the center certain point is, the less density it will have. After some calculations it happens that black hole of the size of whole observed universe will have average density approximately equal to the current average density of the observed universe.
Probably sounds speculative, but there is the possibility that the entire universe is the black hole, which would mean that here's kinda no size limitation for it.
Nice link to one of Sabine's articles, just watched her on PBS spacetime live
Also she has a yt channel. I follow her, pbs and this.
yess! i believe in the weinstein- Sabine debate, Sabine totally won !!
Why was the video removed?
@@plexiglasscorn one person spent too much time with the mic talking about things they knew 99% audience wouldn't understand (and lots of off topic opinions) Matt et al may have decided it didn't meet quality standards
Kyle Bowles you noticed that too, he wouldn’t give a word to Sabine towards the end. But I missed first half, and the reason why two people left 😕
sir please explain some stuffs about the firewall paradox and does sphaggetification occurs when two black holes merge together ??
Does higher temperature from energy of black hole lower entropy which in turn holds more information?
I always thought -- but can't remember the source I heard it from -- that two virtual particles forming near the event horizon of a black hole reduced its mass because the one that ends up falling into the black hole has negative mass. In the explanation given in the video, how does the process lead to the black hole potentially shrinking to nothing and eventually vanishing? Thanks!
In that particle-pair analogy indeed the infalling particle must have negative energy. But it's only a bad analogy and shouldn't be taken literally. See the links in the video description.
Hi, do gravitational waves get "stretched" by dark energy like electromagnetic waves do?
Hey Don, what was it that made you want to study particle physics?
Since you're covering Black Holes at the moment, I have a question that has been puzzling me for years. In Kip Thorne's book on the "Science of Interstellar" he says "The common idea that a black hole is just made of very compacted matter is wrong. It may have been created by very compacted matter, but the matter is gone. It's been completely destroyed, it no longer exists."
If I'm interpreting this correctly, and I assume I am not, then I have a big problem. Firstly, if the extreme warping of spacetime, that is a black hole, is formed by a large mass in an incredibly small volume, if that mass "disappears" what stops the fabric of spacetime from springing back to being flat. Secondly, and has happened to the mass anyway?
The mass didn't disappear, the matter did. The mass-energy of that matter is still inside the black hole. We don't really have a useful, agreed on description of what happened to the matter, though. All we can say from outside the black hole is that there is an energy density big enough to create a horizon, and very little about what goes on inside.
What Narf Whals said. That's why he's in the hall of heroes.
@@drdon5205 :) if you're taking recommendations for that thedeemon seems to be talking a lot of sense
@@narfwhals7843 I am in total agreement.
3:49 no one expected to see stock videos in a Don Lincoln video )
How did you calculate the weight of 1kg near the black hole? I can't reproduce these numbers.
Could be an error, but it was done simply. It was Newtonian gravity at a radius of Schwarzchild radius plus 15,000 m.
why gravitational force between two masses varies for different masses. Why there is not a constant pull for a particular mass?
Speaking of BH temperature, what happens to heat energy of in-falling objects?
Does it contribute to the mass or somehow get converted to BH kinetic energy or radiated away?
Question
Can black holes can clear the mystery of gravity particle and complete the standard model
What about the evaporation of fast rotating black holes? Do they evaporate faster and faster? Could this lead to the explosion of such black holes?
Hey Don ! Hope this is noticed ! i'm unable to grasp how virtual particles can be "boosted" into becoming real particles, this virtual-to-real particle conversion, cuz, the escaping stuff only "appears" as electromagnetic radiation & must be massless, is E=mc sq. used? Is the quantum fluctuation somehow "trapped" & made a permanent excitation in a quantum field?
See the links he posted in the video description. It is quite unintuitive.
E=MC^2 only works without movement, it changes at higher speeds
Question: Since virtual particles of the quantum foam have a measurable energy as seen in the Casimir effect, doesn't empty space have a non-zero temperature way higher than the temperature of a black hole? Won't the virtual foam prevent black hole evaporation?
This vacuum energy is not in the form of real particles that have temperature, empty space doesn't have any non-zero temperature. Our universe is currently not that empty, meaning there's a lot of cosmic microwave background in the form or real photons with real energy.
Question: Dark stars from the early universe can be reason for formation of supermassive black holes?
You talked about blackholes absorbing radiation and growing. This got me thinking. Could blackholes have formed before recombination and how much of their mass could be accounted for by absorbing all of that abundant light even if they only formed after recombination but possibly still near it?
Weight reduction through virtual particle divergence is not a short term strategy. It also requires that you stop accreting mass.
Doctor Lincoln,
Do you have any idea about what would happen to a black hole once it evaporates to a point where ir is no longer massive enough to remain a black hole?
There's no such limit, it can be a black hole with any mass > 0.
Does the "lifetime of a black hole" take into account the time the univers need to cool down ? Or do we need to add that time ?
We need to add
*I have a question*: if someone falls into a black hole, time slows down, so wouldn't the black hole shrink down before you're able to enter it?
Ps in Italian, Don is a prefix that means "sir", it's like lady but for males
not from the perspective of the observer falling in time would appear "normal for them at least outside the event horizon (who knows what goes on inside lol) The outside universe would indeed rush by towards heat death but what that would look like is hard to say.
On the other hand an outside observer would see the guy falling into the black hole slow down and get red-shifted towards being unobservable.
Dragrath1 since from one prospective it falls into the black hole and for the other one it doesn't, doesn't that break general relativity? Because if you drop a large quantity of mass into a black hole (enough to make it significantly bigger) you will se it grow but at the same time that big mass thing never crossed the event horizon, how's that possible
Hello Mr. Don. Can you survive gravitational waves when you are with your spaces let’s say just a few AU’s away from 2 colliding black holes? How far away do you need to be to stay safe?
In a recent episode, it was shown that the effect is negligible from 10,000 km.
If the time "stops" for the particle when falling inside the black hole, wouldn't that particle be "frozen in time" then?
I would expect, in order to "pay the bill" and annihilate the pair of virtual particles, the escaped one would have to disappear instead.
How can we be so sure, it's not the other way around, having the outside particle to evaporate and the black hole to grow instead?
You're drawing concusions from a heuristic illustration that wasn't ever adequate. To reason about what happens there you need to see the actual Hawking radiation mechanism, see the links in the video description.
En nuestra clase de hoy, nuestro profesor será don Don .... That's how we introduce you in spanish, saludos!!
Assuming a copper atom falls into a black hole all by itself. What becomes of it and/or it's components as it takes its place "inside" the black hole? i.e., does it remain a copper atom (only smaller) or are all the quarks, gluons and electrons squished out?
Sir what do you think is more fundamental to the universe vibrations or energy?
Hi "Don" Don or "Don of Dones". I have a question you can't refuse about blackholes family and the fact(?) that singularity forms in the distant future(?). Can we fall into a blackholes and never get close to the singularity before the black holes evaporates and we get outside? maybe a little toasted but consevating our infomation and send you regrets. Thx very much "Don" Don, I owe you a favor.
Question: If we take two entangled particles and throw one of 'em into a black hole and measure the spin of the other, can we predict the spin of the one that fell into the black hole?
Yes, we can predict the spin of the entangled particle that fell into the black hole. But we can never verify the prediction so it isn’t a very useful prediction. If we toss one glove of a pair without looking at it into a black hole, we can look at the hand of glove retained and predict the hand of the one that went in. The two situations are similar except for a quantum mechanics rule making the decision for the entangled particle pair.
OK ,but this glove analogy you gave is called hidden variables and quantum entanglement is much different from that.
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I’m just explaining the idea, what it is you know afterwards. How the spin or glove decision is made isn’t really important here. The word “similar” means comparable but not the same.
Besides, quantum entanglement is based on hidden variables like gloves are. But quantum entanglement uses hidden *global* variables, not hidden *local* variables like gloves, at least to the best of our current understanding. Hidden local variables have been ruled out for quantum entanglement. The only other possibility is faster than light information travel and that is also ruled out. Do you have another explanation that doesn't entail magic?
Once our ship pass the event horizon of a rotating black hole , could we send information outside by resisting or not resisting gravity using our engines ? I mean, as we are also rotating , accelerating inwards or outwards should change the rotational speed and the dragging effect of the black hole differently, which could be measured from the outside ( same as a skater moving the arms inwards or outwards ...)
What happen to singularity after evaporation of black hole ???
I tried to find on internet but not satisfactory answer
Please answer
Do rotating black holes really have two event horizons? & if so how weird will that be for someone who's observing someone falling into that black hole?
Is there information on surface of black hole that is radiated (Hawking) away with energy from black hole?
In the way virtual photons carry the interaction of electrons, could the spontaneous virtual particles in quantum foam be the result of interactions of dark matter or some as of yet unknown field?
I have a question
According to E^2=(mc^2)^2 + (pc)^2 Photon does not have energy
But according to Planck's constant/wavelength Photon has energy
Please explain.
m=0 but p > 0, so E > 0. In this case E = pc. Photons have momentum. Momentum in quantum mechanics is defined quite differently from classical mechanics, it's not mv, it has to do with a wave's frequency in space.
Does black hole evaporation happen by only emitting photons or are other virtual particles emitted?
Others too, but massive ones later, when the temperature (energy flow) is high enough.
Sir, can you please explain C,P,T and symmetry ??
Hi Dr. Lincon,
Great series, better than Netflix! I am curious with a may be wrong assumption, If a black hole losses mass because Hawking radiation, but it precisely became a black hole because the enormous mass, in some moment it is not any more and turns in some kind of strange star?
No, because it always stays smaller than its Schwartzchild radius.
No, while the mass is positive it remains below the Schwarzschild's radius and so it remains a black hole. The space cannot "unwarp" until the last moment of the BH where it explodes and leaves flat space.
Hi Don, will black holes always evaporate completely? There is a mass limit for objects to collapse into black holes, is there a reverse where an evaporating black hole will spit out a remnant that doesn't project a Schwartzschild radius beyond its own radius? (Above the size of a particle)
This is still an open question. When a black hole gets small enough (round about Planck length), its temperature is so high, that the particles it is suppose to emit have the same energy as the black hole itself. It can't emit particles with smaller energy, because that would make the black hole so small and hot, that it should radiate particles more massive than itself.
This is one of those things that breaks physics, and requires unification of general relativity and quantum mechanics to get a sensible answer.
Can a gravitational wave stretch and squeeze it black hole?
Thanks for answering my question about the evaporating black holes..... still, there is another question left... photons are a way of energy... is there a possibility that this energy will cluster, maybe start creating new gasses and thus creating a new universe? I once was told that enery doesn't cease to exist. Philosofically it would mean that universe is able to recreate itself.