How to Understand the Image of a Black Hole

Publicerades den 9 apr 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


  • 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):

    • Not images like a snapshot of your mother. You're looking at virtual reality as per algorithms predicated on assumptions, with these assumptions predicated on some facts and plenty of theoretical bias. Astrophysicists haven't even tested the results against other theories regarding what the image(s) represent due to academic consensus thinking-permitted protocol for funding. You might consider another explanation before you justify to the gullible and uneducated public all the monies, grants, endowments and salaries needed to conduct science as it's conducted today, often without experimental evidence. For scientists bent on truth, not glory, look here to consider another point of view:


    • And you only say that nothing can come out of a black hole because there is no proof that hawking radiation exists?

  • I’ve watched this several times and recommended it to friends. Great explanation!! I really appreciate how you carefully introduce each aspect and then build on it in a logical and understandable way.

  • Mind = Blown! 5/5. Veritasium is the highest quality of content on youtube.

  • As usual Hollywood was ahead of nasa

  • Funny how the new space race came back when flat earth became huge lmao

  • Of course, nowhere „in“ that black hole will exist a singularity. Due to relativistic effects and us being an outside observer, the formation of a singularity will not happen until an infinite amount of time will have passed. All the matter that went „into“ the black hole has yet to pass the event horizon, but since apparently (to us) no time is passing for this matter, it just can’t. It takes quite literally forever for that matter to form a singularity.

  • If we can detect Hawking Radiation. Could we not paint a picture with that?

  • I wish I could have watched this when it came out because he called it exactly

  • This is an image of the plasma torus at the galactic centre with the Birkeland current which extends from it photoshopped out.

  • Helpful thank you

  • ...1.5 shwar...1.21 gigwatts or 65,000,000,000,000,000,000au it's all hogwash lol

  • yawns,, gotta go back to school to even get any idea what he just said.

  • You should have started with SPOILER ALERT!

  • It match well what the photo show

  • im offended

  • Hats off.. Very well explained and indeed image was the way you described before release of image

  • Great explanation, cheers!

  • A+

  • The difference in brightness around the ' hole ' indicates a rotation ? (the axis of rotation being the line dividing the areas of intensity ? Effecting the doppler beaming ?)

  • Paint Shop Joke!!!!!

  • thx for this I used it for some cool stuff

  • Thank you - my brain, is now broken

  • Can you please make it a bit more simplified?

  • Ull r totally wrong,,,I'll explain it to you

  • Wonderfull video. But are you sure the photon has no mass? I recall from high school physics the conclusion of the photon having the 'heavy' mass, in the context of it being bent by the nearby gravity (solar exclipse experiment which confirmed Einstein calculation). In other words, you could also reason why would photon be affected by gravity at all, if it had no mass?🤔😊 Photon is an electromagnetic field. Substance and the field are the two forms of the existance of matter. So, seems logical that the field has a (albeit small) mass, and is thus affected by gravity...(of the situation😋).

    • Mass of the sun or black hole curves significantly space-time, light goes straight lines in space time, I.e in a significantly curved space, so the trajectory is curved. No need for mass to the photons, and it would break the standard model in ways that would be really tough to reconcile. No observation ever disproved the absence of mass to the photons and EM field.

    • Paint Shop Joke!!!!

  • Thanks for the explanation. My students love your videos... I love your videos. Haha had my chemistry students create their own chemical bonding songs after we watched your atoms and bonding song videos haha Keep up the good fight!


  • So Basically, we are looking "into your deep black hole?!?!?! and it is skewed like we don't understand it?" But it is our own black holes?!?!

  • Inside the black hole the trapped light will make it white!

  • Nice explanation..... 😁

  • ada yg dateng dari kok bisa ?

  • Nice Prediction..Awesome....

  • Nice job.

  • Once you go black you dont go back

  • My friends, wait no further! If you wanna see the black hole, get a mirror, turn around, bend over and spread your büťt cheeks. There at the center, you will find the black hole! And as a bonus, I shall tell you how to obtain the elusive dark matter! Next time you take a dump, look at the bottom of the toilet bowl before you flush. There you will find the dark matter!! Kthxbye!!!

  • Please explain to me how I can look into a black hole and see the back of my head because I cannot wrap my head around how that is possible? I mean, I understand it's not physically possible for me to get there and do that, but how is it theoretically possible?

  • If you enjoyed this .... you will love this video

  • I thought that I will learn something about cgi and photoshop but there is just a bunch of religious crapping

  • PLEASE Make A Video or Two on NEBULA!

  • To be totally honest I want to know what happens once the threshold of the even horizon is crossed. I have a lot of questions. Why are there so many paradoxes involved if the "Black hole" is spherical in nature? Why can we theoretically see the back side of it? So if we are talking about possibly and infinitesimal object with infinite gravity that light photons can not escape aren't we talking about what may describe the Bing Bang event? I would love to know. Maybe it is taking the energy from this space time and regurgitating it out in another reality. which would be another universe. We may be looking at the first part of a big bang in another Universe which could be deemed the Multiverse theory. We have theories about our "Big Bang" but what if our Universe started a long long time ago with Light and energy being sucked up in a black hole in another Universe? I think what worries me more is that we are looking dead on on the earth and what happens when the jets let go in common perceptions of Astrophysics? We have never witnessed it in real time because how can we? We witness the past and it seems plausible and say what does 500 years mean in the timelines we are talking about? We think we know but we just don't. As for the jets I think we are lucky looking at the image. It seems like we are looking at it sort of tilted toward us and explains why the bottom is brighter than the top. Regardless of everything I am still in awe. I am surprised very few people are though. Ahh, Black hole, who cares? The first image of one and no on cares it seems. We are looking at it how it was in time and not how it is in space. But to me it holds great physical awe and great philosophical awe and it is a big deal. It should be a big deal with everyone too. Ask most people and it was just a passing news story.

  • The team producing a fuzzy photo from literally 8 telescopes scattered across the globes is not nearly as impressive as this ni🈁a perfectly drawing their photo beforehand... This dude just put the G in Genius...💯

  • rowan and martin WOLFGANG very interesting but i tink you're STUPID

  • There are no such things as black holes. What is at the center of every galaxy is a plasmoid. It is an electrodynamic effect of electromagnetism. Black Hole or Plasmoid?

  • When the great Walter Lewin himself declares your video as the best explanation yet on youtube he has ever seen, you know you have reached new heights. Amazing video! Keep rocking :)

  • Very good video! Always keep creating nice content and you will get bigger very quickly! Subscribe to our channel and so we should subscribe back to you!

  • How could you keep a straight face, talking about something no one has seen. The Black Hole Surrounded by The White. The Black Hole is the Ghetto and the Poor Areas. The White Surrounding the Black Ball is the White Elites Living Outside the Continents. Waiting for Us to Die off.

  • love the explanation

  • can black wholes more likely einstein rosen bridges or time travelprotals

  • Your totally wrong. I've been around a black hole and all I saw was nappy pubes and it stunk. Oh wait! That was a black chick I banged in the ass. Sorry

  • Black holes feel good

  • The visual aids were great

  • Not images like a snapshot of your mother. You're looking at virtual reality as per algorithms predicated on assumptions, with these assumptions predicated on some facts and plenty of theoretical bias. Astrophysicists haven't even tested the results against other theories regarding what the image(s) represent due to academic consensus thinking-permitted protocol for funding. You might consider another explanation before you justify to the gullible and uneducated public all the monies, grants, endowments and salaries needed to conduct science as it's conducted today, often without experimental evidence. For scientists bent on truth, not glory, look here to consider another point of view:

  • Wouldn't what we call neutron star that is massive enough look just the same if it had accretion disk? How can we positively tell if it has an event horizon or not? What would be the lowest electromagnetic radiation frequency emitted by a massive neutron star?

  • What would it look like top down? Just a solid light mass?

  • Dude, Dr. Walter Lewin mentioned you on his channel as the go-to for this image. 👏👏👏

  • Where can i bow down before you? The prediction was on point.

  • if that matter is going close to the speed of light, then time must be moving really incredibly slow for it... so for it to throw out enough light for us to be able to see it this brightly, then it must be insanely powerful. I can't imagine how much light it must be emitting for each of it's own local seconds. what sort of energy output are we even looking at here?

  • The image was created using algorithms based on what they already expected to see. Half the image is CGI, basically. Veritasium, it would be interesting if you could do a response video to this:

  • this work by kaite about black hole not true because her algorithm fourier inverse transform ,this algorithm tends to pool anarchic values toward the center but if an algorithm is used DCT instead of in fouirer inverse The market results do not show up correctly


  • “That misses the GRAVITY of the situation” 😂

  • Ah Derek, you found your niche for sure. You're a science lecturer who make things easier to understand. Thanks!!! and dead on!

  • what do you mean light has no mass

  • 6:15 How can something be infinite and yet have an edge or end?

  • Good enough for me. Thank You, for the effort.

  • man why is it everytime i visit this channel lately my description is auto translated.. yet not on others??did veritasium create this.. so annoying, i want on english ;o

  • Best video about black hole😍 Clarity in his explanations 👌 Simply marvellous

  • Very nice video! Where did you get all the numbers? Do you have any suggestions for further reading?

  • I think it's spinning, extremely fast by compression. The harder it compresses the more energy it spins. Think about a spinning object, once it goes fast enough as if the light goes through it, but it's not. It's that simple.

  • So would we ever see an accretion disk exactly perpendicular to our telescopes, since black hole's gravity would bend away from us? What we might possibly see is light rays further away from 2.6rs since those at 2.6rs would just be bent away from the line of sight of our telescopes, unless they're able to complete the full orbit and just escape towards us. Am I wrong here?

  • forget to mention radio waves

  • Walter Levis recommended this.

  • Thanks for a very accessible and visual explanation of this phenomenon. I've learned some new curious things today without fully submerging myself into hardcore science for tens of years :)

  • In that darkened studio setting I find the blindingly white teeth intolerably distracting. Either have a cup of tea and a decent curry, mate, or issue a sunglasses warning. Do teeth like that fluoresce in UV light? Ye gods. It's beyond a pantomime joke. Yes, of course I'm being rude, insensitive, judgemental and cruel. But hey, it's like having a tattoo or a piercing: people do it to stand out and draw attention to themselves. Well, you've succeeded. You drew my attention. I'm truly sorry that my response isn't what you paid all that money for. ;-)

    • How is it possible that you can possible have such a long-winded response to the way someone looks? If pearly teeth is all it takes then I hope you don't get out that much or else you'll be writing a novel every day.

  • Kate Bauman did 6% of the Work but Got 100% of the Credit :)

  • you got it right!

  • A black hole is a sphere? Or is it like a funnel?

  • Excellent explanation Veritasium ! Thank you.

  • Dude, you bet your .... everything..... on science! And YOU won!!!! Bravo!!! What can I say? Jos palaria!

  • If light rays are being bent around the black hole and a black hole is spherical shouldnt the black hole then be encapsulated in a shell of light. Shouldnt some black holes be a giant ball of light? (obviously ones with matter around it)

  • Please guys stop saying is a hole I couldn't even find a name for this thing is out of our known science maybe the mechanic Quantico can explains that

  • So if a black hole is black, and we can see the color black, shouldn't we call it invisible then?

  • How the black hole obtains very high gravitational field ? likely Nuclear force is also very high ?

  • not even space is straight

  • is there any similarity b/w Sun & Black Hole ?

  • Isn't 1:30 wrong....or is messier 87, and saggitarius a the same

  • My question is , that the black hole is 500 million light years away . How can electromagnetic waves travel that large a distance without getting completely auttenuated , nothing comes in the way for 500 million light years , and also wouldn't the data we receive be 500 million years old?

  • I wonder, does the fact that we do not see a line going through the "black circle" in the middle mean we happen to look perpendicularly to the accretion disk ? It seems to me that is the only spacial configuration that explains this particular lack. Well, either that or a lack of image definition...

  • How many of u watched the video more than once to understand it

  • The chalkboard nailed it.

  • Just look at our butt. The black hole is always there!

  • I hope to see 4k footage of a black hole in the next years.

  • Mock black hole Of Science! You made my childhood smile with that Bill Nye reference

  • Your prediction in the 20 first seconds was actually not too far.

  • I could care less about Space...I'm only concerned when an asteroid will hit earth. Everything about Space sounds like science fiction to me, and another alien language.

  • So if the image of the black hole is face-on to us rather than edge-on, shouldn't the relativistic effect disappear, since no part of the accretion disk is traveling at relativistic speeds towards or away from us?

  • Black holes hurt my brain. I'm just going to look at funny cats instead. Do you like cats?

  • Thanks for such a brilliantly clear and easy to understand, visual description of a black hole. Great work!

  • Thanks. Great video. Referred by Joe Scott: Answers With Joe.

  • 3:30 Oops. I think something broke inside my brain. Damnit!