A Brief History of Black Holes 

Waw, that was a really good prediction! 5:49 October 6th 2020: Sir Roger Penrose won the 2020 Nobelprize in physics "for the discovery that black hole formation is a robust prediction of the general theory of relativity," which he shared with Reinhard Genzel and Andrea Ghez.

I'm addicted to her channel. She has such a rare quality of expression when it comes to complex concepts.

Thankyou Sabine. I’m the kind of person who wants to know, but is utterly incapable of following the math. You have made the cosmos less elusive, even though I still don’t know how the toaster works.

Penrose definitely deserves the Nobel. He is such a refreshing thinker.

She has changed my pronunciation of Einstein.

Thanks for the great video, Dr. Hossenfelder! Although I would like to mention that the possibility of gravitational bodies so massive that light could not escape them has actually been around for a long time. In the 18th century, John Michell speculated that extremely massive stars might have gravity so intense that light could not leave their surface. Around the same time, Laplace also hypothesized similarly massive stars, calling them corps obscurs (dark bodies). Certainly these classical black holes based on Newtonian physics are very different from Einsteinian black holes as we know them, but they were discussed in scientific circles and even had mathematical models.

Dr Hossenfelder, I think the Nobel prize committee watches your videos 😅. Congratulations to Penrose 🔥 truly deserved.

Sabine explains so heartwarmingly clearly what happens at the limits of the physics I know, that it is a pleasure to listen to her, even if I only understand a fraction of it.

Not only great videos, but also prophetic gifts. Keep them coming! ;)

Not only does Penrose deserve a Nobel Prize for his Black Hole work, he needs to be taken seriously on his Cyclical Universe theory.

Thank you - lucid as always. it has also been my opinion, albeit as a layman, that Penrose has earned the Nobel. Also, much of his thinking is so original that many of his ideas have yet to see fruition.

Thank you much for your link. I was involved in the first LiGO data project. The wave process was a wonderful way to celebrate Albert's equation. 100 years past...

Love the outfit, you look like you’ve come straight from tatooine

A great video, as usual. A small typo: "The Schwarzschild radius of the Sun for example is a few *thousand* miles..." If we drop the thousand we're good.

Roger Penrose won the Nobel Prize today - and you called it!

Thanks for the video. Somehow, you make it easier for us, not physicists, to understand the beauty of astrophysics . Greetings from Brazil !

The Penrose Diagram incorporates an Event Horizon. If I understand it correctly, it implies that once you've breached the Event Horizon, Space-Time becomes Time-Space. & any physical motion through space, does not end up being physical motion through space; but rather it translates as motion through time. So your fate is sealed. You can only go to The Singularity. Even turning your head to try to look back out at the universe is not even an option. You can & will do only 1 thing: Go to The Singularity. Totally off topic, but my wife is on the phone talking about making Mutzbraten on our Grillstand & Grillspieß this weekend, & my mouth is already watering!! Sorry, but that makes me like a kid on Christmas Day🤣

Thank you for captions and translations.

I agree Roger Penrose should have a nobel prize for this. I'd also love to hear you and him discuss cosmic inflation :) I just finished reading your book by the way. I find your central argument very compelling: i suspect most scientists shy away from wanting to consider it because it's so very far from what they are interested in. Namely: you describe a highly psychological effect, whilst physics is generally mathematical. Trying to grapple with your question takes them out of their comfort zones. But physicists are also humans and this does need to be taken into account, especially when there's a lack of experimental data. I notice that some of the greatest physicists were also quite comfortable discussing emotions and science, but it's rare (Einstein, Feynman).

Einsteins Math of General Relativity was created out of the typical architect approach of 1.function 2.form and 3. formalization. Einstein reasoned that attraction (1.Function) can be explained as a contraction of spacetime (2. Form) for which he needed (new) tensor calculus to make the according geometry work (3.Formalization). So this math is actually the only logical result of the very PHYSICAL idea that gravity could be explained by contraction of spacetime. Sure, developing the math was a brilliant achievement of Einstein but the key insight is that contraction of spacetime is the underlying cause of gravity. So once you figure out which math goes with this notion, it is rather trivial that this very same math can then next 'predict' additional things in retrospect as well. But again Math is only a tool (any machine can nowadays generate such formalization). The key insight is that 'molding of spacetime' is the underlying form and this insight requires CREATIVITY, which is our greatest asset. So I am very sorry for all math geeks; you are NOT the ones that give humanity new paths, your job is just to create the correct road signs that go with them...

I'm a simple man. When I see a new video by Sabine, I click.

It seems incredible that until so recently we had such limited grasp of what most children now understand as almost mundane fact. I wonder how long before we grasp that we also cannot consume indefinitely lest we turn our own world into an inescapable black hole for life.

I'm on a Sabine Hossenfelder bender. Great content, much of which is not available in other physics channels.

Sabine way better pace in your videos now! For those which English is out second language it's really helpful!

When I first clicked on this video the image of Sabine against the starlight background was SOOOO impressive, she appeared as a goddess of knowledge. Her lectures are no less impressive.

Sabine, congratulations! Roger Penrose was awarded the Nobel Prize, as you suggested he should. You certainly know that, I just wanted to congratulate you!

Thank you for captions!

You are the prettiest scientist I love your channel

I was a child in Europe, your Closed Captions are not needed. I understand you just fine. Thanks anyhoo.🐾

Thank You! I love everything that deals with these mysterious things.

you are my newest addition to Heroic Thinkers, Doers and Illuminators. Thank You. I am a proponent of a gentle investigation of "Our " nature as formed by "Nature" . . .

Again another absolutely fantastic informative and well presented video, just as I have come to expect from you. But seriously, „miles“? Is that your way to appeal to a more general audience?

Hello there Sabine. Informative presentation. Thank u for explaining it in an easy to understand lesson.

What a beautiful presentation, thank you.

I love the Professor Doctor's enunciation.

Thanks for captions

Congratulations Sabine you called it. More importantly many thanks to both you and Sir Roger for helping us understand a bit more hopefully.

Hey Sabine, great video as usual. Just wanted to ask, does your theory of superdeterminism rules out quantum randomness?

Sabine! I absolutely love your channel. Thank you for this content.

I love your videos. They appeal to my secret nerd in me. 😀

I agree with you about Roger Penrose! While he has not been in the public eye he has certainly been the backbone of proving the theories of Einstein and of course Hawking. WIthout his ideas and no doubt influence on Hawking and others we would not have the current understanding.

Sabine, please add some more equations to your video as you have done in others. Like the Schwartzschield radius calculation. Just to see it without explanation would be nice.

Thoroughly agree regarding Penrose and a Nobel Prize. He's been on a number of very interesting podcasts lately where he's discussed a lot more than just black holes and despite his never getting the Nobel he seems incredibly at ease in his accomplishments, for which I rather think he deserves 2 Nobel Prizes. Cheers.

Sabine's lectures are always fascinating for my life

I see Dr Hossenfelder as a wise Jedi with that outfit on. Loved this video. Thank you!

Sabine, if you were a baseball pro you would knock the ball out of the park every time you stepped up to the plate. Outstanding. Thank you.

This complexity creates the potential outcomes to establish the loops that form the structure of the form

The trickiest thing to explain about black holes is that the center, the singularity, is a finite inevitable future, not a geometric center that things move toward. Once inside the horizon, things don't "fall" but "exist" to the singularity. Imagine this: it's 3:15 pm and you are sitting there minding your own business, pondering astrophysics and philosophy. Soon it'll be 3:17. Do you "move" toward 3:17? Do you have a choice? If you did get up and walk, or ride a bike, or drive a car, or flew in a giant nuclear powered space rocket with racing stripes, you'll still find the time to be 3:17 pretty soon. Who sees what on whoever else's watch or digital alarm clock, doesn't matter, though relativity can give you all the details. It's about existing, and you "arrive" at the future. You can't stop it any more than you can stop time itself. Except, once you "arrive" at the singularity, you're crushed by space itself in all three dimensions, in a space that if you could measure it infinitely fast (not using light) you'd find circular boundary conditions, space goes only so far in any direction and loops back to the same point, like a great circle on a globe, but in all three dimensions. And that distance around shrinks at the speed of light to zero. Once it's zero, you won't exist, and time, as you experience it, simply ceases.

Roger Penrose 2020 Dr. Penrose was awarded ½ the 2020 Nobel Prize in Physics for “the discovery that black hole formation is a robust prediction of the general theory of relativity.” To understand Penrose's contributions, we must first understand the state of black hole science in the early 1960s.Oct 15, 2020

I love how she pronounces "Schwarzschild'', i'mma use it from now on.

I love your accent! English is not my first language and I like to hear different accents! excellent video as always, thank you!

It is rather amazing that mathematics can indeed be the precursor to actually finding the derived physical object. Yet, there is more. I derived earlier that speed inside the black hole is to be defined as E/kg or M2/s2 or C2 as a constant. The event horizon is the only place where an object must have equal speed both in (outside) spacetime terms (C) as well as in it interior virtual energymass terms (C2). Hence it solves mathematically for C2=C meaning C is either 0 or 1, which predicts the entropic 'qubit' value of a singularity as per Erik Verlinde entropic approach of gravity....Sabine, could you therefor pls also provide a short history of the concept of an ENERGETIC singularity, and (both) its Schwarzschild solutions. It is a topic hardly anyone touches upon, yet rather important, when applied e.g. to understanding our Sun and our wider solar system as outer barrier....Thnx!

Interesting video. It would be even better to mention the discovery of gravitional waves from black hole pairs by LIGO Virgo detectors as that corresponds well with the GR prediction.

Love your accent and straight delivery

What happens inside a black hole? Do atoms and sub atomic particles still exist? Could I invite people over? Is there room for guests? Or is there just complete cessation of everything? Please discuss Sabine.

Andrea Gezz: ".....bigger IS better!" [with a hint of a giggle in her voice]

I have enjoyed Penrose books. His Road to Reality is more a labyrinth than a road but I never tire of opening it. I hope too he is awarded in this cycle of the universe.

Ms Hossenfelder, I would really appreciate your opinion on the recent claims that the universe itself might be conscious, please? Many thanks for your kind attention and for all the high-quality and very informative content you produce.

And he's got the the Nobel prize!

000 on Y Axis toward 003 is activated to store, retrieve and manage the build process

This form, is manifested on the form level, but needs to close its loops at 3.5 for 3.6 control of location to be able to read the next instructions

I'm not anglophone but I use the language to communicate outside my sphere. It is always very pleasing to hear different accents and especially how some words are pronounced in their natal language. I speak a language which evolved from Vulgar Latin and nowadays it has speakers and fans all around the planet. So, yay to different accents!

Correction 6:16-18 :) Thanks für deine Videos, Sabine! :)

Sabine - Would you kindly do a series on thermodynamics?

Sabine, some people still think a black hole is a hole. Can it be mentioned clearly by a scientist that a black hole is not an empty hole but physically a spherical object like any stars, except that its mass is so dense that it doesn't permit even light to escape.

A couple of questions, if I might: 1. How is it that we know, or alternatively why do we believe, that once the mass compresses below the Schwarzschild radius, it will compress to a point? I ask that because: 2. If the necessary condition for a black hole is that light is unable to escape it, then isn't it sufficient for the mass to be compressed below the Schwarzschild radius even if it doesn't compress to a point?

If we can never observe something falling into the black hole because for us, external observers, the crossing of an object by the horizon of events takes an infinite amount of time, how then can we detect actual black holes? Shouldn't we only detect a bunch of matter in the vicinity of the event horizon but not the black hole itself because it's yet to be created? From Wikipedia While most of the energy released during gravitational collapse is emitted very quickly, an outside observer does not actually see the end of this process. Even though the collapse takes a finite amount of time from the reference frame of infalling matter, a distant observer would see the infalling material slow and halt just above the event horizon, due to gravitational time dilation. Light from the collapsing material takes longer and longer to reach the observer, with the light emitted just before the event horizon forms delayed an infinite amount of time. Thus the external observer never sees the formation of the event horizon; instead, the collapsing material seems to become dimmer and increasingly red-shifted, eventually fading away.

Penrose deserve a Nobel, a Knighthood, a key to most city's and a night at a Strip club!

Thanks so much Sabine. 💫💫💫💥

Please don't burn or bury me after I have up and died. Drop me down that one-way well. Let me be spaghettified!

Remember, Sabine has said that a scientist will say a thing exists if it is useful to explain an observation. This doesn't mean that black holes have no ontological reality, but it does leave the door open, and while scientists who study black holes may indeed have no doubt of their existence, as a free human, I reserve the right to doubt everything.

Great summary.

Can you make a video about rotating Kerr black holes? As I understand it, they are more realistic than Schwarzschild black holes due to rotation, and also inside their horizon(s) extremely interesting things happen!

As I have said many times, I wish I had the math to be able to deeply understand what you are telling us. Maybe it's not too late. In any case, please keep up the great work -- I learn a great deal from your videos!

Sabina rocking the Franciscan drip

The notion of black holes originates with Oppenheimer and Snyder’s metric in 1939. In 1965, Roger Penrose claimed that the O&S metric gave rise to trapped surfaces, i.e., regions of space from which no light rays could escape, and that within such surfaces black-hole formation is inevitable. But the metric is faulty. Trevor Marshall’s landmark article (2012) uses differential geometry to show that a simple modification of the O&S metric, fully consistent with GR, enables all radial light rays originating in the interior to escape to the exterior. There is no trapped surface and no black hole; on the contrary, there is a stable end state with finite density, contained within a sphere of Schwarzschild radius, contracting ever more slowly on itself over infinite time. Such solutions may be seen as counter-intuitive if, above a certain density, “no force can countervail against gravity”. Indeed, they require gravity to be repulsive in the extreme high regime, where its energy density is comparable to mass densities. It therefore fits intuitively with the field interpretation of gravity. By contrast, the purely geometric interpretation based on the extreme form of the equivalence principle has no light-ray connectivity, so is not consistent with causality, so is counter-intuitive. Stephen Hawking, in 2014, also said they do not exist, because there is no event horizon (Stephen Hawking: 'There are no black holes': Notion of an 'event horizon', from which nothing can escape, is incompatible with quantum theory, physicist claims-nature.com; Information Preservation and Weather Forecasting for Black Holes-arxiv.org). Laura Mersini-Houghton, a physics professor in the College of Arts and Sciences of UNC-Chapel Hill, has proven mathematically they can never form (There Are No Such Things as Black Holes, 2015-universetoday; Carolina’s Laura Mersini-Houghton shows that black holes do not exist-uncnews.unc.edu; Rethinking the origins of the universe - unc.edu; Black holes do NOT exist: Big Bang theory wrong claims scientist, math proves it-dailymail.co.uk). She shows that as a star collapses, in conventional physics scenario, it should give off "Hawking radiation," which should convert the collapsing mass to energy and thereby cause this mass to shrink in amount, so much that it no longer has the density needed to become a black hole. This also invalidates space tunnels and stargate portals. It also calls string theory into question, at least its claim that as a superstring moves in time it warps the 'fabric' of space around it producing black holes, space tunnels, and other fantasy structures. The April, 2019 'photo' is a simulation, because of missing information, not a real photo, and the algorithms were "tuned" by checking that they produced the expected results using trial data from quasar observations, so it was made according to how scientists think a black hole should look like--they are built by assumptions instead of facts, so it's entirely subjective (see 'Black Holes' Refuted by Wallace Thornhill - You Tube; Claims of a Black Hole Image, Sky Scholar, You Tube; Scientific Analysis: the Claim of a Black Hole Image, Sky Scholar, You Tube; The Black Hole Image: Data Fabrication Master Class, Sky Scholar, You Tube). And the image was hyped and used as a publicity stunt and propaganda ploy.

Sabine spoke and the Nobel Prize Committee happily obliged ;-)

Congratulations Mr. Penrose.

Sabine, one topic I'd love to hear you discuss is the details of event horizon formation. As we know not only mass density but also energy momentum fluxes and especially pressure contribute to the stress energy tensor. Many people have a mental image of a star shrinking and the event horizon beginning to form outside it, but is really so? Does the pressure at the center matter ( heh heh heh ) more at some point? -- not a physicist, just a humble numerical analysis guy

It is amazing how blackholes were considered impossible and probably uncommon. Your explanation implies it’s a definite outcome of Einstein’s equations and that they appear an exceedingly common event. It appears that blackholes are very numerous. They certainly appear massive energy drivers of our galaxy and perhaps provide gravity stream to their local vicinity to drive the orbit and movement of other celestial object. So nice summary. Thanks. . Do you have any idea how many there are?

Merci C’est toujours un grand plaisir

Sabine, I think we are missing something in our interpretation of Bells' theorem and the superdeterministic and probability aspect that comes with it. Just bear with me for a second and consider this: Suppose the error we have been making for 100 years now, lies in our hidden shared assumption that there is only ONE way do define the grid in which any movement can occur: Namely: we only consider the spacetime continuum. However, if we assume there is actually an additional and concurrent DUAL grid setting (where energy forms the grid, like in expressing electron distances in eV's) governing the subatomic world, then all issues we have with Bell's theorem can be classically solved. For starters, we would not be limited to the burden of C limited speeds. Moreover, if indeed there is such an 'energy as a grid setting' then this means that if we have two particles which have the exact same spin energy along all three axis (and at the same 'mass' clock) then we would have the dual version of SPATIAL locality , namely ENERGY locality or 'quantum entanglement'. This in turn means there is NO INFORMATION that needs to cross the spacetime continuum at speeds higher than C. The two entangled particles simply ARE already ADJACENT in energy grid terms so we can manipulate one by changing the property of the other, just like we can in the case of SPATIAL locality. Please tell me you see the inherent logic in all of this ? if so, you may also see how this dual setup solves the religious quest for people regarding symmetry in physics (namely: what you gain as 'energy as a particle' , you lose in terms of 'energy in its surrounding grid' ). So you get an ultimate answer as to why people got lost in math (!!) and how to get out...Can you pls do a video on this idea of continuum DUALISM?

Sabine - Your videos have gotten better and more interesting since I found your Channel (or was that RU-vid’s click-bot?) … anyway … Thanks for keeping me “engaged” … 🖖🏽

Thank you

Can you please make a video explaining our current understanding of binary black hole systems?

The universe is expanding for the further away, the faster it moves from us. What would we observe differently if our 'universe' was falling in one big black hole?

Yup, Sir Roger

Very interesting video. Thanks 😊

if you could watch someone fall into a "Black Hole" you would never see them cross the event horizon because it would take till end of the universe. On the other hand if you were the one falling you would see all of time passing in an instant and you would not cross the event horizon until the end of the universe even if it only took a few seconds for you. The point is that this happens for any matter that fall in. So while there are extremely compact objects that are close to the Schwarzschild radius they are not yet true black holes as it will take till the end of time for anything to cross the event horizon. Abhas Mitra has proven this mathematically with his eternally collapsing object paper. I would love to see a video from Sabine Hossenfelder on this!

Well, some thoughts: *Schwarzschild's original solution was concerned with a masspoint; it didn't contain what we nowadays call the 'singularity' (where the curvature blows up as r^-6 - cf. MTW), and the 'event horizon' corresponds to that same masspoint. For the details, check arxiv.org/pdf/physics/9905030.pdf - the key equation is the definition of his new radial coord, R(r):=(r^3+a^3)^1/3 *What warrants us to talk about this solution even for non-points is a result known as Birkhoff's theo; basically, it's the GR version of Newton's shell theo... *Of course, not all BHs are Schwarzschild; nowadays, the term BH refers to a family of equilibrium solutions called Kerr-Newman *the Penrose-Hawking theo, like any other math theo, is as good as the assumptions used in proving it; violate those, and you can bypass a BH altogether *the distinction is scarcely made in the literature, but there are _astrophysical_ BHs, whose existence nobody really questions (Sag A*, M87, etc.), and _theoretical_ BHs, which the first part of the vid talked about; identifying these two is, I believe, far from indisputable, as I hope you can glimmer from some of the bullets above...

Loved the video and have sent it to a few others to take a look.

Interesting summary. In principle the "spherical collapse" isn't so easy to explain, since you'r expect Rayleigh-Taylor instabilities during the compression, which would render it non-isotropic. This is something that inertial confinement fusion [and nuclear weapons] scientists know well.

I like your stuffs,the way you present it, just astonishing!

I always thank you for your videos. I like a lot. 👍

Danke schoen Sabine

Yes sir penrose deserves noble prize

Sabine should do a full "video course" on "Modern Physics" for Great Courses.

Penrose surely does deserve a Nobel, but we would have stumbled upon it because of the need to explain astronomical observation, galactic motion, quasars, etc.

Each galaxy was a single mass of quark-gluon plasma when it was born. They were shrapnel from a collision. Their rotation rate determined if they would be spiral or elliptical galaxies. Our galaxy spread the matter into a disk with a bulbous center. The center separated from the disk and our black hole was formed. Black holes have cooled the least. They are still quark gluon plasma so there is no light. As they cool, light is finally emitted as they slowly turn into neutron stars.

if a BH can have a charge how can the charge escape? if I take a ton of electrons and compress it into a BH the negative charge is an information that escaped the BH.