How to Understand the Black Hole Image

  • Published: 09 April 2019
  • We have just seen the first image of a black hole, the supermassive black hole in the galaxy M87 with a mass 6.5 billion times that of our sun. But what is that image really showing us?

    This is an awesome paper on the topic by J.P. Luminet:
    Image of a spherical black hole with thin accretion disk
    Astronomy and Astrophysics, vol. 75, no. 1-2, May 1979, p. 228-235

    Using my every day intuition I wondered: will we see the "shadow" of the black hole even if we're looking edge on at the accretion disk? The answer is yes because the black hole warps space-time, so even if we wouldn't normally be able to see the back of the accretion disk, we can in this case because its light is bent up and over the black hole. Similarly we can see light from the bottom of the back of the accretion disk because it's bent under the bottom of the black hole. Plus there are additional images from light that does a half turn around the black hole leading to the inner rings.

    What about the black hole "shadow" itself? Well initially I thought it can't be an image of the event horizon because it's so much bigger (2.6 times bigger). But if you trace back the rays, you find that for every point in the shadow, there is a corresponding ray that traces back to the event horizon. So in fact from our one observing location, we see all sides of the event horizon simultaneously! In fact infinitely many of these images, accounting for the virtually infinite number of times a photon can orbit the black hole before falling in. The edge of the shadow is due to the photon sphere - the radius at which light goes around in closed orbits. If a light ray coming in at an oblique angle just skims the photon sphere and then travels on to our telescopes, that is the closest 'impact parameter' possible, and it occurs at sqrt(27)/2*r_s

    Huge thanks to:
    Prof. Geraint Lewis
    University of Sydney
    Like him, I'm hoping (predicting?) we'll see some moving images of black holes tomorrow

    Prof. Rana Adhikari

    Riccardo Antonelli - for excellent images of black holes, simulations and ray-tracing code, check out:

    The Event Horizon Telescope Collaboration
    Check out their resources and get your local link for the livestream here:

    Special thanks to Patreon supporters:
    Donal Botkin, Michael Krugman, Ron Neal, Stan Presolski, Terrance Shepherd, Penward Rhyme

    Filming by Raquel Nuno
    Animation by Maria Raykova

Comments • 14 415

  • Veritasium
    Veritasium   8 months back

    OK, just over an hour to go! This is the link to the Washington DC National Science Foundation livestream:
    Click here for links to other live streams (there are several available in different countries):

    • Pradeep Yadav
      Pradeep Yadav  2 months back

      @Rayagoldendropofsun Sunlightelectrorays nothing is trapped in a solid if you heat it the whol solid will get converted to vapour or react with air to form other gaseous compound

    • Pradeep Yadav
      Pradeep Yadav  2 months back

      @Rayagoldendropofsun Sunlightelectrorays nonsense it's not the way you mention actually water molecules in cloud do not get separated as hydrogen and oxygen they remain in h2o form in vapour state they can only be separated by electrolysis or similar kind of method in which energy is required which is much larger than that is used to convert it into vapour state

    • Rayagoldendropofsun Sunlightelectrorays
      Rayagoldendropofsun Sunlightelectrorays  2 months back

      Pradeep Yadav - Credence clear water revival is a super fine music band with a mega hit song: "Have U ever seen the rain coming down" ?
      If U did, U have in live motion experienced a physical act of Gravity being DEBUNKED . Water/ rain falling downward was once atmospheric gases roaming free oxygen and hydrogen, but when trapped together making water they lost their motion and falls downward, as another song goes, "raindrops keep falling on my head".
      Whenever rising atmospheric gases oxygen and hydrogen bonds together making water, which is a state of solid motionless mass, they fall downward as RAINDROPS from lost it's gaseous molecular motion. This shows downward falling motion has nothing to do with Gravity. The factual cause, and rightful owner of downward falling motion is TRAPPED GAS MOLECULES/ GAS BONDING. This is a simple physical fact visible to the naked eyes, unlike Newton's and Einstein's mythical theories so complex they themselves don't believe it.
      Another way to put it. Solid objects on fire releases trapped gas molecules with new life in rising motion upwards into the atmosphere as gas smoke visible to the naked eyes ! Those gas smoke/ gas molecules was once trapped within that solid objects keeping it grounded. All solid object stays surface grounded because of its motionless trapped gas molecules, which are connected to the earth ENERGY CONSERVATION SYSTEM by way of its Electrons, including us humans.
      This is grade school science, and should be easily understood.

      "Where is the gas molecules in a solid".
      Strange U ask this question when it's clearly stated in that post saying, GAS BONDING the making of solid objects. The universe is made of gas molecules, so is earth and it's solid objects !

      Einstein Gravitational equations is a concepts of math and not physics, if it is, bring me a physical connection to the physical universe, same as the mechanism of GAS BONDING is physically connected as a see and touch part of the wider universe.

    • Pradeep Yadav
      Pradeep Yadav  2 months back

      @Rayagoldendropofsun Sunlightelectrorays why would gas molecules go up why not it goes down and what is weight can you explain based on your theory ???? Stars motion ??? Etc the current theory of gravity has the answers and these things can be explained by Einstein gravitational theory but what you propose sounds absurd to me it doesn't make sense and you are not able to explain clearly what you are trying to say

  • Mr Pickle
    Mr Pickle  6 hours back

    0:29 hehe

    • Yours Truely
      Yours Truely  6 hours back

      Its not a photo its a radio cgi. No pixels involved.. Vlbi.. Radio telescopes.. They won a prize... Fundrazing.

      • N E W
        N E W  1 days back

        I did not understand a single word you said as you are too elony

        • PLAYER X
          PLAYER X  2 days back

          Omg you got it right

          • Ven Vex
            Ven Vex  2 days back

            Then how come Quasars are spitting out light?

            • Souvik Dutta
              Souvik Dutta  3 days back


              • John De Jong
                John De Jong  3 days back

                My questions are : If the material and gases within the secretion disk move with a substantial part of the speed of light being milions of degrees hot and' it leaves the edge of the secretiondisk into the black hole 1. Why does it become invisable? 2. If it travels so fast what within the black hole puts a end to it's increable speed. 3. Does te speed of the material and gases increase if it moves towards the centre.

                • John De Jong
                  John De Jong  2 days back

                  @Thomas Kundera that is correct however onely when it pases the eventhorizon but ther is a lot of space between the inner adge of the secretion disc and the eventhorizon of the black hole.

                • Thomas Kundera
                  Thomas Kundera  2 days back

                  When the matter pass the horizon, you can't see it anymore: no light will ever go out.

              • Nick Venture
                Nick Venture  3 days back

                Does the view of a black hole always look the same no matter your orientation bc of how it bends light around it? Still trying to wrap my head around a 2d object in a 3d space..

                • Kevin Anthony
                  Kevin Anthony  4 days back

                  Lol...the "gravity" of the situation...

                  • Mimoh Joshi
                    Mimoh Joshi  4 days back

                    That was truly amazing.. it's crystal clear right now !!

                    • Kobil Shakur
                      Kobil Shakur  5 days back

                      1.5 SSR? Wouldn't it be like just outside of it?

                      • K Z
                        K Z  5 days back

                        Minf*ed and I love it!🤩

                        • Gambit
                          Gambit  5 days back

                          fail lol

                          • RobertsMrtn
                            RobertsMrtn  5 days back

                            This is based on the assumption that the so-called Accretion disk exists. It could be a sphear of objects orbiting the large mass and not a disk. I would also like to point out that this image does not prove the existence of so-called Black Holes. It shows only that there is a large mass present which is bending light in this way. I have good reason to be skeptical about these things. Please message me for more information.

                            • Thomas Kundera
                              Thomas Kundera  11 hours back

                              @RobertsMrtn : Why did you had to publish in a scam journal?
                              None of the regular ones would accept your work?

                            • RobertsMrtn
                              RobertsMrtn  1 days back

                              @Thomas Kundera I had it on but the journal asked me to delete it because it was being picked up by their plagiarism checks. I can give you the gist of what the paper is about. It uses the Equivalence Principle developed by Einstien to drive formulas relating time dilation and acceleration due to gravity. It concludes that it is not possible to slow the propagation of light to zero with gravitational fields.

                            • Thomas Kundera
                              Thomas Kundera  1 days back

                              @RobertsMrtn : [repost] It's not already in preprint on arxiv or something?

                            • RobertsMrtn
                              RobertsMrtn  2 days back

                              @Thomas Kundera I have written a paper on this topic which is being reviewed for publication by Annals of Mathematics and Physics. I will be happy to provide you with the link if/when the paper is published.

                            • Thomas Kundera
                              Thomas Kundera  2 days back

                              _". I have good reason to be skeptical about these things. "_
                              Fine. Then you should be one of the top world-class astrophysicist of the word. May we see your credentials?
                              And links to the certainly very praised scientific publications where you develop your ideas?

                              Or, way more likely, maybe just another EU crank?

                          • Arpad Farkas
                            Arpad Farkas  6 days back

                            Most likely many people before me realized this, but I truly am amazed by that in theory, by looking at a black hole, we could see the past of our own planet. I guess that that is not too probable, since we are not stacionary, to be in the way of the returning photons, wich started their journey a couple million years ago from Earth...

                            • phail89
                              phail89  6 days back

                              You just blew my mind like 2 or 3 times in one video 😂 haha

                              • Brent Caldwell
                                Brent Caldwell  7 days back

                                0:32 - the GRAVITY of the situation you say? 🤣😉

                                • Fox Dylan
                                  Fox Dylan  7 days back

                                  Came here from Joe Scott, looking to be mesmerised

                                  • Aspartame Is Healthy
                                    Aspartame Is Healthy  1 weeks back

                                    Thank you, this is explained so clearly, especially with visuals.

                                    • Nirmal kumar
                                      Nirmal kumar  1 weeks back

                                      U cleared my doubts tq u

                                      • Professor Davidson Viana

                                        O conteúdo deste canal é excelente! Fiz um vídeo bem simples sobre o assunto que gostaria da apreciação dos interessados: Sou doutor em Física e estou iniciando timidamente um canal com a proposta de mostrar que com materiais de baixo custo (ou nenhum) podemos entender conceitos chave da ciência atual entre outros temas variados. Quem quiser apoiar, inscreva-se neste canal/perfil (professor Davidson Viana) e me sigam também no instagram @vianadavidson. Serei humildemente grato pelo apoio e farei por merecer cada inscrito com bastante trabalho! Abraços!

                                        • Prabin Paudel
                                          Prabin Paudel  1 weeks back

                                          See you in few months or year perhaps, as youtube commands, again.😌

                                          • Chrissen Gemmill
                                            Chrissen Gemmill  1 weeks back

                                            Why are they not called black balls? no, seriously...

                                            • vikas srivastava
                                              vikas srivastava  1 weeks back

                                              I have a couple of questions -
                                              1. Why is that part of the of accretion disc not visible which is diametrically across the black hole.
                                              2. Why is imaging of black hole at center of our galaxy more difficult that imaging the M87 black hole.

                                              • Oleg Orlov
                                                Oleg Orlov  2 weeks back

                                                Чувак то почти угадал...

                                                • SmartrMelons
                                                  SmartrMelons  2 weeks back

                                                  Memories of you and Bill Nye on gender binary still has me questioning your veracity. Sorry, but you should know there's only two sexes. Unless you can name a third? That was the most embarrassing video I've ever seen from people who claim to be scientific. Cred. -10.

                                                  • Sk C
                                                    Sk C  2 weeks back

                                                    From Which calculation or a idea, the black hole was introduced and at how much degree it’s an accurate.
                                                    Plz say me 👍👍

                                                    • AgentQQ8
                                                      AgentQQ8  2 weeks back

                                                      Really well laid out explanation, thank you - subscribed!

                                                      • PanzarMetal
                                                        PanzarMetal  2 weeks back

                                                        Does anyone else have a feeling he's parroting other channels?

                                                        • Juan J 11805 Rodriguez
                                                          Juan J 11805 Rodriguez  2 weeks back

                                                          Starts off with "on Wednesday, April 10, 2019" me: *checks date it was uploaded* Date: *April 9th 2019*

                                                          • Jay Williams
                                                            Jay Williams  2 weeks back

                                                            Wow, now I can explain it to my 5 year old son... Wish there were pics of Black Holes when I was 5 lol...

                                                            • Thiago Trevisan de Souza

                                                              Very good !!

                                                              • 검정색
                                                                검정색  2 weeks back

                                                                7:27 그럼 어느 방향에서 블랙홀을 보더라도 다 저렇게 보일려나? 예시에서는 종이로 표현했으니 옆에서 보면 옆면이 보이지만..실제 블랙홀을 네명이 동서남북으로 쳐다보면 다 같은 이미지를 보게 되는 거겠죠?

                                                                • Siddarth Nair
                                                                  Siddarth Nair  2 weeks back

                                                                  This is the best and simple explanation of how a black hole is. Thank you!

                                                                  • Bobo Kesen
                                                                    Bobo Kesen  2 weeks back

                                                                    You are a genius! :) fantastically explained... Thank you! :)

                                                                    • Nagyitas
                                                                      Nagyitas  2 weeks back

                                                                      saying "looking perpendecular to the acc disc" doesn't make a lot of sense. we see the exact same shape/pattern of the disc on every angle.

                                                                      • Abidin Shaik
                                                                        Abidin Shaik  2 weeks back

                                                                        I have a question, where god stands here?

                                                                        • Ben G
                                                                          Ben G  2 weeks back

                                                                          8:13 could someone try to explain to me why the matter traveling towards us looks brighter?

                                                                          • Ben G
                                                                            Ben G  2 weeks back

                                                                            @magnvsmarcvs ill look into it. thanks

                                                                          • magnvsmarcvs
                                                                            magnvsmarcvs  2 weeks back

                                                                            Doppler effect , wavelenghts compression and shieeet .

                                                                        • multilen ten
                                                                          multilen ten  3 weeks back

                                                                          That's the best explanation. But my question is,
                                                                          Black holes are always represented as 2d with well and singularity.
                                                                          🌍. 🚀 🕳️
                                                                          So is it a black sphere?

                                                                          • magnvsmarcvs
                                                                            magnvsmarcvs  2 weeks back

                                                                            Sphered hole , everything you observe is 2d , you cannot percieve 3d . NOBODY CAN :)

                                                                        • philippe illinger
                                                                          philippe illinger  3 weeks back

                                                                          Black holes don't exist !!! Have a look to JANUS ( JPP )...Very very interresting !!!

                                                                          • philippe illinger
                                                                            philippe illinger  2 days back

                                                                            @Thomas Kundera Black holes, dark energie, dark matter, are Voluntary gridlocks...used to wasting time...

                                                                          • Thomas Kundera
                                                                            Thomas Kundera  2 days back

                                                                            Why dd you chose to believe that ?

                                                                        • Aberdolph Linkler
                                                                          Aberdolph Linkler  3 weeks back

                                                                          Can someone please explain to me why infinity is not an acceptable answer in math, but it's accepted when it comes to physics...

                                                                          Kind of creating the basis that everything we know in physics is wrong because physics constantly uses infinity.

                                                                          • Thomas Kundera
                                                                            Thomas Kundera  2 days back

                                                                            Infinity is way more acceptable in math (see transfinite numbers for example) than in physics.
                                                                            Usually, in physics, when you come to some "singularity" that doesn't means reality goes "infinite", but that our physics touched its limits.

                                                                            There may be another physics that would be needed to understand what those infinity means...

                                                                        • samual williamson
                                                                          samual williamson  3 weeks back

                                                                          Eiffel 65 predicted it 👏🐼🎍👀👀👀👀👀👀

                                                                          • wate wut
                                                                            wate wut  3 weeks back

                                                                            ive got eyeballs

                                                                            • ItsFamLesPanda
                                                                              ItsFamLesPanda  3 weeks back

                                                                              good job ^_^ even me understood what u want to say ^_^

                                                                              • multilen ten
                                                                                multilen ten  3 weeks back

                                                                                Thank u, great content and best explanation

                                                                                • blessing xaba
                                                                                  blessing xaba  3 weeks back

                                                                                  Thanks what a brilliant explanation, I was confused about a black hole but now I have a better understanding, you're super,my thumb is up

                                                                                  • Praveen Kumar
                                                                                    Praveen Kumar  4 weeks back

                                                                                    Oh lol... you are saying what i just imagined!!😲😳
                                                                                    I too have something inside my head