15 Subatomic Stories: The truth about black holes
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- čas přidán 22. 05. 2024
- Black holes are one of the most perplexing phenomena in the cosmos. There are many misconceptions in the popular press about their properties. In episode 15 of Subatomic Stories, Fermilab’s Dr. Don Lincoln begins a several-episode mini-series talking about this fascinating phenomenon.
Subatomic Stories Episode 14: Quantum gravity
• 14 Subatomic Stories: ...
Big Mysteries: Extra dimensions
• Big Mysteries: Extra D...
Fermilab special relativity videos (playlist)
• How to travel faster t...
History of Fermilab logo
history.fnal.gov/exhibit/imag...
Fermilab physics 101:
www.fnal.gov/pub/science/part...
Fermilab home page:
fnal.gov
Black hole image credit:
NOVA/WGBH - Věda a technologie
Dr Don Lincoln you are awesome!
Dr. Lincoln, thank you for always seperating Math, Philosophy and Science.
Of course - it's like a toddler's food, where they don't want foods touching.
Don't want the math and philosophy touching the good stuff!
@@drdon5205 If we ever come to know everything, you'll still have your comedy career to fall back on!!
sepArating*
@@hardcard254 www.thefreedictionary.com/seperate
I will use A from now on.
After several weeks away from my You Tube subscription page, I had a lot of videos to watch, so I had to pick and choose the ones I wanted to catch the most. No surprise that Dr. Don was at the top of the list.
Thank you so much for putting these out! Just re-watched the subatomic stories series today, now this yay!
At last I hear someone say "singularities are maths things not physics things" 👍
On the other hand, the distinction between the physics thing and the math thing in this case is essentially just philosophical.
That is the most lucid statement I've heard a scientist say in years. 👍
Thank you for clarifying that the singularity is a mathematical quirk! That always confused me. I'm sure a real singularity violates many many things, but the Pauli Exclusion Principle comes to mind
well actually it could easily not violate that, it just needs to be a bosonic singularity.
Watch ZapPhisics' video on that, it's great
@ could not find it, could you send it over here?
@ Kugelblitz!
@ As the matter that went into the black hole is crushed beyond neutron degeneracy, there is no matter left that is governed by the PEP. The matter has been converted to energy(not sure?) and the spacetime curvature that is left behind causes the gravity well - and this is the opinion of today's best gravity expert - Kip Thorne. Although I probably didn't explain very well.
Ol' Bluelips The Pauli Exclusion Principle is certainly broken for smaller black holes. That’s what makes black holes different from neutron stars. And that’s why we have trouble describing the inside of the black hole.
love these videos, just wish they were longer!!! like maybe 10 minutes longer? i always leave wanting more.
When this is all over, I'll miss these bookshelf-side chats.
Agreed, always happy when these are posted
This all will probably be happening to some degree for at least 3 years.
Dr. Lincoln mentioned the phrase "non-rotating" several times in this video. But doesn't every star have some (or quite a bit) angular momentum? If so, isn't likely that a black hole that results from a collapse of a star also has angular momentum? So the big question is: how are rotating black holes different than non-rotating black holes?
They are different (I'm sure that will be in a future episode), and yes, it is thought that all real BHs should be rotating, but in the early days of the theory's development it was much easier to start by assuming a non-rotating BH to work out the maths.
The Kerr metric is weird. Other universes, time travel, ringularities, etc.
As far as I know, non-rotating black holes are just theoretical constructions meant to simplify the calculations while retaining some key features of the phenomenon.
About the difference between rotating and non-rotating black holes, I think both Veritasium and PBS Space Time have videos on it.
They are called Kerr Black holes czcams.com/video/UjgGdGzDFiM/video.html
@@evandroserafim733 Yes, like extremal black holes.
Question: I read an article recently about algebraic geometry, and how it might be the key to unifying general relativity and quantum mechanics. What have you heard of this, and what are your thoughts about the potential for this approach?
Dr Lincoln, I love your series - great video as always. Only one remark: since Karl Schwarzschild was a German, he was most definitely not pronounced „Schwarzs-Child“. „Sch“ is the German writing for the English „sh“. „Schwarz“ is „black“ and „Schild“ is „shield“ (and is actually pronounced quite similarly in German, only with a briefer „i“ like in „to build“) So he was litterally called „black-shield“ - which makes the „black-shield“ radius of a black hole even more fitting! (And less „child“ish!) 😀
shwarts-shillt /ʃwɑʀtsʃilt/
I'd just like to say that one of your colleagues, Paul R., is woefully underappreciated. His groundbreaking work clearly merits doubling his salary and giving him one of those emeritus positions where you don't have to actually work. It's entirely coincidental that we attended college together.
Hey Dr. Lincoln, thank you for these short videos! They're so informative and I love the viewer comments section. I have a question though about gravity and the higgs field: if the higgs field gives mass to matter, then is there a connection between the higgs field and gravity?
Gravity is not about mass, it's about energy. The higgs field gives mass to fundamental particles like the quarks inside protons, but most of the mass of the matter we interact with is in the binding energy in the proton, not fundamental particles. And that is what bends spacetime and creates gravity.
@@narfwhals7843 that's really fascinating! Thank you for clarifying!
Question: You spent a life dedicated to academia and then directed it towards youtube and digital outreach. In honor of the third law, how has a life of youtube and digital outreach affected you as an academic?
😂
Whats a third law? 😂
@@plexiglasscorn Newton's 3rd law.
@@plexiglasscorn for every action, there's an equal and opposite reaction.
I know Newtons third law, but never heard of third law 😁 besides, it does not apply to cats
Subatomic Stories is such a wonderful thing! I come for the subject and stay for the addressed comments. Keep it up!
I think this topic has set a record for the number of questions that can be answered with a simple "No."
Wow, I got in there 1 minute after release and was the 21st to watch. Just shows you've gotta be at the right place at the right time! Thanks for the videos.
I got the video notification on my phone app 10 minutes before I could see the video on my PC. Pretty sure it's a relativity thing since my PC is so much faster than my phone it's clock must run slower.
That story of the Fermilab logo is super cool! (....get it? :D)
Awesome explaination
Interesting video as always Dr. Don! I am hoping that you are going to discuss the temperature of Black Holes & why it approaches absolute zero. Also, what are the differences between Anyons, Fermions, and Bosons? Thanks for these awesome videos! Stay safe......
what is the smallest object that we have ever measured gravity effects coming from it?
Gravity can only be seen in small objects by its effect. Dust can be in orbit around a planet, but the gravity of the dust mote is much too small to measure as yet.
dbmail545 “smallest” in size, I think black holes but smallest in mass that HUMANS can notice it’s deffo those lead ball experiments they did to find G
Love from my wife.
@@brogant6793 just remember that Newtonian gravity requires both gravitational objects have gravity or the math doesn't work.
A neutrino.
A minor pronunciation error, Don. Schwarzschild doesn't end with the "child" pronunciation. In German, schwarz means black and schild means shield, and is pronounced very similar to shield in English. Just make it short, like shild instead of shield, and you'll be spot on!
Did pronounce it right the first time though!
That's true. I'm not criticising, only educating. I like Don.
@@crouchingtigerhiddenadam1352 Not quite, but almost. Still too much child in the first one. 🙃
@@johngrey5806 it's hard not to be a fan (even if there is the odd mistake.)
Correct. The banking family is Roth-shield not Roth-child as it is commonly pronounced in America. English is not our first language.
You absolute chad, Don. You didn't mention it or reply to the comment, but you (or whoever controls it) renamed the episodes of this series with numerical labels involved. However, I might request (15) or [15] or something like that for more clarity, as I almost thought this was a compilation for a moment. Sorry to be a pain, but it's absolutely a step in the right direction, you guys. Thanks a zillion planck-doodads.
Excellent.... thanks.
Hi Dr. Don, thanks for that answer! I've heard of gravity being diluted by extra dimensions but I didn't know about the link between the extra dimensions and "massive" gravitons. That's a really cool connection! Sadly I think extra dimensions siphoning off gravitons has become less likely because of results from the LHC but I can't off hand remember what led to that conclusion.
Wild thought, what if dark matter was a non-local excitation of a field? An electron is where the electron field is excited, in one place, what if what we see as dark matter was a large excitation of that field so that no particle is seen, but just energy in that field has built up?
It wouldn't have to be the electron field either, it could be the Higgs field or a quark field or even the neutrino field.
Now how to test that…
That's the thing about quantization: Fields can only have discrete energy levels. There is no energy level of the electron field between an electron existing and not existing, much like there is no energy level of the hydrogen atom between the 1S and 2S states.
@ disks form because of collisions and the averaging of momentum. If the excitation is not "matter" in the classical sense but something like a higher ground state (not exactly but it sort of explains the idea) then there may be nothing to collide.
@@ozzymandius666 They can however carry energy at non discrete levels, that energy could have a mass like effect.
@@emmettobrian1874 I have never heard of any excitation of a fermion field between the ground state and its first harmonic. QM forbids them. Look up the quantum harmonic oscillator.
@@ozzymandius666 the fields are in constant flux and can have various states of excitation. Vacuum fluctuations are the ground state of a field but they can be more or less active. Who knows what the vacuum energy looks like in regions with no "dark matter"
Note: It's Schwarz-Schild, not Schwarzs-child. There is no child. Schild is German for shield and pronounced more like sheeld. Schwarzschild means black shield. And the "a" is pronounced like English people pronounce the "a" in "can't". Shwuhrts-sheeld. 😄
It's always fun to see that even the smartest of people can be ignorant in things that you think are elementary. Seemingly he never studied the German language.
Exactly, what I was about to say. But - by the way - don't you agree, that 'black-shield-radius' is a fantastic name for the event horizon?
@@romanissimo3371 It's in fact a common misunderstanding when learning about it in German. People think it's a descriptive name and not the name of a scientist. 😄
Don't get me started on how he pronounces "quark!"
@@jeffwells1255 quirky!
Six related Questions: 1) Since most of the mass of a proton is not "rest mass" shouldn't a measurement of proton mass look "fuzzy". I.e. on a normal distribution around an average value? 2) Have we seen such a distribution experimentally? 3) If so, what does it look like? 4) If rest mass is a result of the Higgs Field shouldn't rest mass also be on a distribution? 5+6=2+3 for rest mass.
Awsome! Thank you👏
🙀wait! You didn’t explain the moustache! 🙃
Is it possible that cores of black holes, at least those of solar remnants, are held by neutron degeneracy pressure but obscured from observation due to extreme curvature of space-time at the event horizon?
Not neutron degeneracy pressure, but yes. Plank stars. It seems that QM may suggest a maximum density on the order of 10^94 kg/m^3.
@Dr Deuteron That fact is not observable locally nor from infinity. It simply means that a collision with the singularity is inevitable.
@Dr Deuteron I get that part, where all future light cones point to the singularity inside the event horizon. My question is though, if one ought to speculate (because observation is impossible beyond the event horizon), could the neutron degeneracy pressure known to hold most neutron stars intact, also be responsible to keep the singularity at the core of black holes from solar remnants, if that makes sense.
@@ozzymandius666 Ah, I see. Thanks!
Question about the density of a black hole:
I got it that we assume that the matter in black hole is not crushed to literal zero size. But do we have any idea how it is actually distributed? Is it crushed in the middle to a small, but nonzero size? Or is it evenly distributed within the Swartzchild-radius? Or is it unevenly distributed?
I’m thinking about the thought-experiment where we fill the volume of the solar system with athmospheric air, which will immediately be a black hole due to its mass versus size, even though its density is really low, so atoms are not crushed together. And since time stops for an outside observer, we won’t even see any change, it will stay low density.
I don't think there's consensus. However, you could certainly have a black hole with nearly uniform density when it formed. From the inside, the singularity is a moment in time, not a point in space. The universe inside a such black hole would be shrinking towards a big crunch, while staying at roughly uniform density. Sort of like our universe, time-reversed. Very much like, in fact, as the big bang singularity is at a distance in time equal to the Schwarzschild radius of the mass of the observable universe.
Skorj Olafsen There is certainly no consensus, but I don’t know if there is any leading hypothesis.
My other comment right next to it describes how I would imagine the inside of a black hole.
There is no matter inside a black hole, its been converted into the warping of space time. That's covered on one of the Kip Thorne interviews
search for this in youtube "kip thorne closer to truth"
Brandon LastName That’s a maybe. We don’t have the “theory of everything” about what happens with the matter in the black hole, so you cannot say this with certainity. Kip Thorne has one idea, Steven Hawking has another idea, and there are more. We don’t know exactly.
If Dr Lincoln was my primary school physics teacher I can bet that today I would study particles for sure!
Is it possible that gravitons are just really big and we’re looking in the wrong place?
No.
They say dark matter is 85 percent of the universe... an exotic matter that is undetectable but manipulates normal matter... if that is a plausible explanation, then so is yours.
@@tommygunrunner4656 no, we've observed the effects of dark matter. That's why it's plausible
@@olbluelips Nonsense. Galaxy after galaxy is being discovered without the need for the dark matter variable.
Some galaxies do require the extra mass suggesting a lack of understanding. Phenomenon being observed does not shoehorn dark matter as the explanation.
@@tommygunrunner4656 Sorry, dark matter is not "shoehorned" in. There is very good reason to suspect that dark matter really is made up of particles
Is a blackhole’s favorite meal meatball spaghettification?
Thanks for sharing.
Thanks to the best show on youtube😍 Q: How big would a black hole be (Schwarzchild radius), if it contained all the mass in the univers?
13.7 billion Lightyears en.wikipedia.org/wiki/Schwarzschild_radius#Parameters
By no coincidence, it's the age of the universe. It would be the radius of the observable universe but for "inflation" of the early universe. It's not so obvious why this is true, but it's clear that it's no accident. Personally I think it's because the universe is a black hole, just with the singularity in the past instead of in the future - the arrow of time is a tricky business, after all. Reverse time and the observable universe is pretty much what you'd expect the interior of a large block hole to look like, as the singularity is a moment in time, not a point in space, from the inside.
Born too late to crack electromagnetism, born too early to sail throughout the galaxy, born just in time to hear Dr. Lincoln's jokes!
Dr. Lincoln, could you summarize why/how the known dimensions are shaped up the way they are? And, since "singularities" are mathematical entities and not physical, what then the idea of "naked singularity" would stand for?
Fun video. Thanks Don.
You are getiing better and better at making videos. Keep it up
Well I mean there are singularities not only in gravity... Even something as simple as Flow of liquid has singularities in Navier-Stokes equation at a corner... But what we get in real world is turbulence there which we have hard time describing rather than some weird infinities...
no math to describe what happens at those scales. gravity or space wise.
"Subtle is the Lord, malicious He is not." -Einstein.
He may throw dice behind event horizons, but he would not suffer a singularity to live. ;)
@@scottmiller4295 Navier-Stokes doesn't describe stuff at those scales, and its still full of singularities.
@@ozzymandius666 that because singularity = errors your do not have the math to operate there, like quantum gravity.
geometry could describe it just fine and dandy, but QG and other missing pieces your out in the weeds.
@@scottmiller4295 Such is life.
Thank you for the answer, very cool! :D
So interesting!
Awesome sir
Karl is a true hero. Died way to young
As a designer, thanks for short explanation of Fermilab logo. Appreciate that even artsy people like me get attention.
Obviously the answers are classified and they will never spill the beans. I have heard the same story my entire life and nothing changes. 50 years ago I described the
black hole the same as you did almost word for word when my father asked how I was on it.
I really like that crazy part at the end about the haircut. Haha.
🤣🤣🤣
I imaged the bow shockwave from Cygnus x-1 last weekend and even made a CZcams video on it. Black holes amaze me for numerous reasons.
Dr. Lincoln, Subatomic Stories are amazing. Thank you!!!
Kip Thorne said that black holes are the objects made from pure warped space-time, and there's no matter or antimatter under their event horizons: the worldline of every particle the matter made of ends its life in central singularity, which is under event horizon not a location in space, but inevitable future.
He also said that technically these objects are "gravitational solitons": spacetime is curved so strong, that enormous energy of this curvature make the process of spacetime warping to self-sustain itself due to non-linear gravitational effects. Can you explain, please, how does this mechanism work?
Somehow I hadn't realized that the event horizon was quite so close. "Semi-respectable idea" :)
Very interesting series even for non-physicists like myself. At what point/size/mass does something become part of the quantum realm? Is it a cliff-edge or a very fuzzy border?
this guy gets physics .. i graduated with > 90% average for both 1st and 2nd year physics at uni, i wish i had this guy as a teacher, i might have stayed on to do 3rd instead of finishing electronic engineering and becoming a slave to middle management
Your joke about haircuts being so trivial to a "quasi-diety" cracked me up!
@9:24, you nailed the pronunciation!
Hi Dr. Lincoln,
Big fan from Iraq, thank you and all Fermilab to make such hard subject fun and easy to all non physics specialists .
My question is .
What will the discovery of neutrino bring to our daily live or at least to the science community ?.
Hi
I tried to research the black hole heartbeat phenomenon, and I was very confused with what was happening
I'm hoping you can shed a little more light then the black hole itself about this :)
Thank u
Can you explain the Pauli Exclusion Principle as it relates to black holes? I know I'm not the first to ask, but consider this a vote.
I've always vaguely thought Pauli limits the density of a neutron star. Do we know what allows black holes to bypass this limit? Does all their mass get converted to bosons? How?
Thank you again for the fantastic video! One thing that I have real issues with regarding a black hole is how they move through space/time? I have heard a few times that if you are unfortunate enough to be pulled next (and ultimately into ) the event horizon, someone observing from the outside will actually see you slowing down as your time dilation will go up exponentially as you approach that line of no escape. That said, if time is getting massively compressed near the Schwarzschild radius- how does that even horizon makes it way through normal space time? How can it move if the time is being so squished that it has actually stopped? Isn't that area now effectively halted for the entire future of the universe? I hope this question makes it!
Horizons can move. Ask yourself, how can you fly past a black hole? From your POV, the horizon is moving past you.
Thanks for the reply. I guess I am confused with the special case of a black hole where the event horizon represents the massive compression of space/time so I can't really think of it as a "normal" horizon if you know what I mean.
Oftentimes, elementary particles are described as being 'point objects' that occupy zero volume. Could you explain why this is allowed, but a black hole having zero size is not?
That will be explained away as quantum phenomena...the uncertainty principle. They will also argue that black holes evaporate due to hawking radiation which is a quantum phenomena in itself.
Don, thanks for your always excellent and enjoyable videos. A minor comment: The pronunciation of the German name Schwarzschild is not "Schwarzs-child" (which suggests something like "black child", "schwarz" being the German word for "black"), but "Schwarz-schild" (which means "black shield", suggesting perhaps a black shield for the singularity). Wikipedia has the correct pronunciation, also as audio file.
I've already came up with the theory of everything that can't be disputed. How does the universe work? It just does.
Please stay in touch, the Nobel Committee will have good news for you soon.
🤣
In special relativity: When an object is traveling at a significant fraction of the speed of light an external observer would note the object's: clocks run slower; the object has a greater resistance to changes in velocity; and that objects length, measured along the direction of travel, is shorter. All to ensure that both the observer and the object's respective measurements of the speed of light agree.
With General Relativity,
Question: would a distance observer see a similar set of effects to an 'stationary ' object in a strong gravitational field? (Gravitational time dilation is well known, I am curious if gravitational length contraction or gravitational inertial mass are predicted)
Thank you for providing this wonderful and informative series.
Yes, gravitational length contraction also exists. From the point of view of a distant observer distances near the event horizon seem shorter.
Hello, I admire your videos and don't miss any of them. I have two questions:
- During supernovae, I know that the core of the star collapses and forms a black hole while the outer layers are thrown outward. How can the outer layers escape the black hole? Why are they not immediately sucked into the newly created black hole?
- I know that empty space has energy and thus an outward force opposing gravity (so that the universe expands and accelerates). But I can't grasp behind the science of the inflation during the first moments of the universe. Where does the energy of inflation? Could you please explain briefly?
Thanks very much! Cheers!
Watch yesterday's PBS Spacetime video.
Nice
Man I love this guy
Hello DR. Lincoln, Does dark matter can be affected gravitationally and fall into a black hole? Can we theoretically detect a black hole gaining mass without a visible disk of matter around it?
Can the last episode of this series be on the frontier of particle physics. Like what are the next biggest problems to find out and how long until we likely discover them.
Sir I would really appreciate if you shed some light on Electromagnetic molecular black holes. I read in the papers 3 years back SLAC creating molecular black holes with electromagnetic impulses.
How are these different from a gravitational black holes?
Question/introduction: Drop two stones to Grand Canyon (vacuum, Newton's physics) with one second interval. They will pass every horizontal level with that one second time interval even if their speed and distance grows.
Actual question: Drop two stones to a black hole (vacuum, Einstein's physics) with one second interval. What is the time interval the stones hit the singularity?
My guess: there is not much time in the singularity, not a full second. The stones may come down at the same moment.
Fermi Lab's logo is beautiful
Thank you. Always wondered if aliens use dak matter to communicate through. No electro magnetic interfence.
My black-hole inspired question: People talk about space-time moving (especially when explaining why light can't leave a black hole or explaining frame dragging near a spinning black hole). How does space time move near Earth, for example? And why doesn't this end up looking like luminiferous aether?
Specifically, (AIUI) the movement of space time causes the frame dragging which pulls people around with a spinning black hole. Also, light (or anything else) can't leave a black hole event horizon and one of the explanations given is that space time is falling in towards the center at faster than the speed of light, so even at the speed of light, you can't make progress outwards.
So, if we can assign a velocity to space time, then presumably we can describe the velocity of space time around me here on the surface of Earth. So, let's have observer A be inertial and stationary relative to local space time and observer B be inertial and moving at .9 c relative to A. They should be able to measure the frame dragging and therefore determine their speed in an absolute sense, which would violate relativity. (At least Special Relativity and Galilean Relativity. Maybe General Relativity has a way to avoid this issue (like the Lorentz contraction allows the speed of light to be constant in SR)?)
So, did I misinterpret what it means for space time to move? Or is this an analogy that I've applied beyond it's useful range? Is something else going on here?
I'd love if I could understand this issue by the time you finish your series on black holes.
It is an analogy, and a misleading one. Much like the stretching sheet. But it is much easier than explaining how the geometry of spacetime changes. What happens is that the pythogarean theorem, the definition of distance, gets changed so that a step in any direction is also a step in the direction of rotation. But to understand that requires a bit more involvement than imagining spacetime pulls you with it.
General Relativity basically was invented to solve exactly your problem. Observer A thinks he's inertial and moving in a straight line in spacetime and Observer B is accelerating away. Observer B says, oh but Observer A is in a gravitational field, so hes the accelerated one. GR gives us Relativity for accelerated frames, that's why it's "General".
Hi professor , i recently watched a 60 symbols video claiming that the black hole information paradox had been resolved - does this mean that there are no firewalls?
It was resolved long ago by Dr. Leonard Susskind.
Would you say black holes are our best observations of gravity working on small scales (or at least originating from small scales) and are there any plans to utilise them to test general relativity’s limits? As clearly the “ singularity” is indicates some dodgy divergence of maths and physics?
Have you watched that science fiction show on SyFY called "Dark Matter" that ran for three seasons? What did you think of it?
Dear professor, thank you for this amazing series.
If black holes are not literally singularities in space-time, then is it possible that a black hole smaller than Planck length might exist ? Could we expect a black hole of every possible mass ?
If hawking radiation exists, which we're fairly sure it does, then small black holes would evaporate almost instantly. But they can theoretically exist. How they would form is another matter.
@@narfwhals7843 Yeah, process of formation of black holes vary for different mass range, and it is a quest which would require different theories .........
Hi Dr. Lincoln, i have two questions:
1. i´m not sure if im right, but is it correct that inside of black holes time slows down to the point you would think it´s a direction of space? and if its true, would it be possible at least in theory go back in time?
2. Maybe its a silly question but... how does a balck hole looks like? is it a 3D structure? like a sphere?
Inside a black hole space and time swap. There is a PBS Spacetime video on this (I don't remember which one)
*What did we learn from the EHT that we didnt already know or was is so far it just confirmed things* ?
Hey Dr Lincoln. Thanks for being better than any Uni lecturer I had other than the Prof that gave me my first job :)
So I read the universe is bathed in neutrinos, I saw an estimate of 300 odd per CM^3.
What would happen to the neutrinos as a black hole, say Sagittarius A* plows through this medium, and would it leave a neutrino depleted region and/or neutrino jets in its wake ?
How to measure black hole's charge? Is it possible for 2 black holes to have so big negative charge they would repel each other, even if in other circumstances they merge?
Don - From our POV, time becomes indefinitely slow as an object nears the Schwarzschild radius. Doesn't that imply that nothing ever gets around to happening inside that radius? Not to worry about the singularity. When would one ever form?
Hey Dr. Lincoln! Regarding the recent paper concerning hypothetical Planet 9 potentially being a primordial or small black hole, could the implied prevalence of small black holes account for dark matter? Thanks!
Doctor Don Lincoln, I read somewhere that Hawkins radiation has been referenced on a recent paper as a possible indication that information is not lost on a black role. If memory serves, it was stated that an attempt to measuring a particle would cause the appearance of a wormhole linking to another part of the entangled pair inside the black hole. If this is theory holds, would it be reasonable to consider that we could somehow get some information from beyond the event horizon if we send entangled photons strait to it while measuring the others outside? Oh Boy! my brain is about to explode. Cheers!
Hope you don't mind me use this opportunity to ask a real physics pro a very specific question!: Is it accurate to say, while from the outside of the black hole time near the horizon almost seams to stops, from the inside time would move very very fast indeed? Or from another point of view: Is it fair to say that, observed from the outside, black holes do exist long enough for galaxys to form around them, from the inside of the BH the same galaxy is being build and destroyed in the blink of an eye? Thank you so much for sharing you knowledge! Awesome channel!
Hi Don.. if light can scape.from black holes what are those gamma ray bursts from the center of some (quasars)?
You are the Bob Ross of physics ♥️
Nothing but happy little accidents...
Hi Don !
I can't understand the frequently given explanation of Hawking Radiation : pair of particules pop into existence near the event horizon, one escapes, the other is captured. You see radiation coming from the black hole so it must have lost mass. But from the black hole point of view, you see particules coming in, I can't see how it loses mass. Isn't the black hole extracting particules from vacuum energy instead ?
Actually, the energy of the gravitational field is converted to particle/anti-particle pairs, with an energy of the same order as the photons with the same energy as the horizon's radius.
@ Yes we can, just not at the singularity. Horizons are quite well understood, as long as they are bigger than the Plank length by a considerable factor. (say about 10^15 or so)
The story about pairs of particles there is such an oversimplification that it doesn't really work. The actual mechanism is quite different. backreaction.blogspot.com/2015/12/hawking-radiation-is-not-produced-at.html twitter.com/duetosymmetry/status/1283231172160622592 Explaining why the black hole loses energy takes a lot of math, I haven't seen a simple explanation.
@@thedeemon thanks for the link, very interesting
Could you do a video explaining the Pauli Exclusion Principle?
Also yes please could you explain the plank length sorry that's not how you spell it. Is there similarly a plank mass, time, voltage, energy, momentum etc?
Sean Carroll did a video yesterday that covered the exclusion principle and lots of related things. For Planck units, see en.wikipedia.org/wiki/Planck_units
Does the Pauli Exclusion Principle apply to matter within an event horizon?
Question - in your previous videos we learnt that strong force gives matter most of the mass, we also know that mass is responsible for the bend in space time, I may be misunderstanding but what does it imply?
Nothing particularly special. It is any kind of energy that bends spacetime. The mass of the particles comes from the strong force binding energy. That energy bends spacetime.
The next step beyond a neutron star could be a quark star, which would be a single huge nucleus made up of quarks all glued together, but not in triplets. That could be a candidate for what a black hole is.
Hi Don, what's the deal with asymptotic safety? Does it buy you anything for calculations?
Dear Dr. Lincoln,
I have a question about the space around and in black holes:
I have heard many times that the space around black holes essentially flows into the black hole. At the event horizon the space flow exceeds the speed of light, therefore you cannot get out of one. Is this just an analogy or is this what is believed to be the case? To me it makes somewhat sense that space can act similar to a fluid...
I also heard that the particles that falls into the black get crushed down so much that they get annihilated completely similarly to matter and anti matter. and therefore there isn't a singularity instead the mass of the black hole is due to the potential energy of the warped space. Is this believed to be true or also a oversimplification?
It seems plausible that the way quantum gravity works may prevent the formation of black holes smaller than a certain mass. If "cosmic inflation" in the early Big Bang turns out to actually have been variable (higher) speed of light, gated off high density (quark-gluon plasma values), then the minimum black hole mass might even be in the low stellar mass range, and anything of lower mass would never form anything denser than a neutron star (except possibly for transient black hole formation due to overshoot of initial collapse in the case of something just under the minimum mass). Variable speed of light gated off high density might be testable by seismic observations of the most massive neutron stars, if these turn out to have quark-gluon matter cores.
Could you get rid of a black hole by firing electrons into it till you build up enough charge to overcome gravity?
Dr Lincoln, are we sure gravity follows the inverse-square rule at all scales? For instance at the scale of a proton and the scale of a galaxy?
Dear Don,
Thanks for all the great shows.
I have a complex question nobody answered to me so far. Can you?
We can't see behind the event horizon because light would have to be faster than it is to come out at a distance closer that that. On the other hand the closer we come, the slower the time passes so in a subjective way this would change the perception of the relative velocities needed.
I have an idea...
In that case I understood the event horison is nothing fix but instead the distance from the center for an outside "objective" observer and if you get closer to it, with time distorted when being near, the radius moves as well closer to the center.
Or in another interpretation, if your time becomes "slower" when getting closer to the black hole, your event horizon should also become smaller since the subjective time distortion becomes smaller to compared to the "original event horizon position".
So doesn't that mean, sending some drones each one a few kilometers away from each other connected as a "chain", we could look closer to the center than we could from the far outside? Every one would only need to send its observations a bit outside to the next one and we eventually would get a view we couldn't from our sace position. They just have to be close enough to each other to be able to send a signal to the drone next in line (so the relative distortion of the signal being slowed down would be just enough to "refresh" and resend it themselves to their next relay... and eventually outside to us.
Would that work? Could we see past our "normal" event horizon? Why not?
Thanks a lot!
In your own reference frame your clocks always tick at the rate of one second per second. Other observers, farther than you from the gravitational source, will see your clock ticking more slowly than their own clocks, but you will always see your own clock as normal. Also, the size of the event horizon depends only on the mass, not on time.
@@michaelsommers2356 so you mean the distorted time doesn't change anything and even a person right at the event horizon will perceive it at the same position (directly in front of them)? I heard their event horizon would shift since their reference shifts too when coming closer.
Isn't it the case that the time passing will approximate to the one in the black hole for the one "falling down"? I underatood, to an observer falling down the black hole it is not a hard cut as one might assume but more a slowly fading out the nearer they come. So why can't they send a signal a minute before entering "our" event horizon and tell us what they see ahead?
In string theory, additional dimensions are hypothesized to be squashed into an extremely small, subatomic tangle. I'm curious if these sub-atomic folds, these compactified dimensions, could give rise to gravity? We know that mass and frame-dragging produce a gravitational effect-- which is curvature or distortions of spacetime. These sub-atomic folds would be a distortion of spacetime which when added together creates an emergent gravity. Or so my thinking goes.
What does it mean that the roles of space and time flip past the event horizon (or whatever boundary it is)? I can comprehend space becoming like time in the sense that one is inexorably drawn toward the center of the black hole, but what does it mean for time? Does it mean that, according to general relativity, one can move backward in time inside a black hole? Wouldn't that allow someone to indefinitely postpone their movement toward the center?
Actually, it's the opposite. It means that once you cross the event horizon, all your possible world lines lead to the singularity. And because non-accelerating/freefalling reference frames experience the longest proper time, accelerating in any direction will only cause you to reach the singularity *sooner.* So the singularity, once a point in space, has become your future, and trying to move around only affects the duration of your trip.
A video that isn't choked with ads? Rare as a black hole