How to take a picture of a black hole | Katie Bouman

How to take a picture of a black hole | Katie Bouman


In the movie “Interstellar,” we get an up-close look
at a supermassive black hole. Set against a backdrop of bright gas, the black hole’s massive
gravitational pull bends light into a ring. However, this isn’t a real photograph, but a computer graphic rendering — an artistic interpretation
of what a black hole might look like. A hundred years ago, Albert Einstein first published
his theory of general relativity. In the years since then, scientists have provided
a lot of evidence in support of it. But one thing predicted
from this theory, black holes, still have not been directly observed. Although we have some idea
as to what a black hole might look like, we’ve never actually taken
a picture of one before. However, you might be surprised to know
that that may soon change. We may be seeing our first picture
of a black hole in the next couple years. Getting this first picture will come down
to an international team of scientists, an Earth-sized telescope and an algorithm that puts together
the final picture. Although I won’t be able to show you
a real picture of a black hole today, I’d like to give you a brief glimpse
into the effort involved in getting that first picture. My name is Katie Bouman, and I’m a PhD student at MIT. I do research in a computer science lab that works on making computers
see through images and video. But although I’m not an astronomer, today I’d like to show you how I’ve been able to contribute
to this exciting project. If you go out past
the bright city lights tonight, you may just be lucky enough
to see a stunning view of the Milky Way Galaxy. And if you could zoom past
millions of stars, 26,000 light-years toward the heart
of the spiraling Milky Way, we’d eventually reach
a cluster of stars right at the center. Peering past all the galactic dust
with infrared telescopes, astronomers have watched these stars
for over 16 years. But it’s what they don’t see
that is the most spectacular. These stars seem to orbit
an invisible object. By tracking the paths of these stars, astronomers have concluded that the only thing small and heavy
enough to cause this motion is a supermassive black hole — an object so dense that it sucks up
anything that ventures too close — even light. But what happens if we were
to zoom in even further? Is it possible to see something
that, by definition, is impossible to see? Well, it turns out that if we were
to zoom in at radio wavelengths, we’d expect to see a ring of light caused by the gravitational
lensing of hot plasma zipping around the black hole. In other words, the black hole casts a shadow
on this backdrop of bright material, carving out a sphere of darkness. This bright ring reveals
the black hole’s event horizon, where the gravitational pull
becomes so great that not even light can escape. Einstein’s equations predict
the size and shape of this ring, so taking a picture of it
wouldn’t only be really cool, it would also help to verify
that these equations hold in the extreme conditions
around the black hole. However, this black hole
is so far away from us, that from Earth, this ring appears
incredibly small — the same size to us as an orange
on the surface of the moon. That makes taking a picture of it
extremely difficult. Why is that? Well, it all comes down
to a simple equation. Due to a phenomenon called diffraction, there are fundamental limits to the smallest objects
that we can possibly see. This governing equation says
that in order to see smaller and smaller, we need to make our telescope
bigger and bigger. But even with the most powerful
optical telescopes here on Earth, we can’t even get close
to the resolution necessary to image on the surface of the moon. In fact, here I show one of the highest
resolution images ever taken of the moon from Earth. It contains roughly 13,000 pixels, and yet each pixel would contain
over 1.5 million oranges. So how big of a telescope do we need in order to see an orange
on the surface of the moon and, by extension, our black hole? Well, it turns out
that by crunching the numbers, you can easily calculate
that we would need a telescope the size of the entire Earth. (Laughter) If we could build
this Earth-sized telescope, we could just start to make out
that distinctive ring of light indicative of the black
hole’s event horizon. Although this picture wouldn’t contain
all the detail we see in computer graphic renderings, it would allow us to safely get
our first glimpse of the immediate environment
around a black hole. However, as you can imagine, building a single-dish telescope
the size of the Earth is impossible. But in the famous words of Mick Jagger, “You can’t always get what you want, but if you try sometimes,
you just might find you get what you need.” And by connecting telescopes
from around the world, an international collaboration
called the Event Horizon Telescope is creating a computational telescope
the size of the Earth, capable of resolving structure on the scale of a black
hole’s event horizon. This network of telescopes is scheduled
to take its very first picture of a black hole next year. Each telescope in the worldwide
network works together. Linked through the precise timing
of atomic clocks, teams of researchers at each
of the sites freeze light by collecting thousands
of terabytes of data. This data is then processed in a lab
right here in Massachusetts. So how does this even work? Remember if we want to see the black hole
in the center of our galaxy, we need to build this impossibly large
Earth-sized telescope? For just a second,
let’s pretend we could build a telescope the size of the Earth. This would be a little bit
like turning the Earth into a giant spinning disco ball. Each individual mirror would collect light that we could then combine
together to make a picture. However, now let’s say
we remove most of those mirrors so only a few remained. We could still try to combine
this information together, but now there are a lot of holes. These remaining mirrors represent
the locations where we have telescopes. This is an incredibly small number
of measurements to make a picture from. But although we only collect light
at a few telescope locations, as the Earth rotates, we get to see
other new measurements. In other words, as the disco ball spins,
those mirrors change locations and we get to observe
different parts of the image. The imaging algorithms we develop
fill in the missing gaps of the disco ball in order to reconstruct
the underlying black hole image. If we had telescopes located
everywhere on the globe — in other words, the entire disco ball — this would be trivial. However, we only see a few samples,
and for that reason, there are an infinite number
of possible images that are perfectly consistent
with our telescope measurements. However, not all images are created equal. Some of those images look more like
what we think of as images than others. And so, my role in helping to take
the first image of a black hole is to design algorithms that find
the most reasonable image that also fits the telescope measurements. Just as a forensic sketch artist
uses limited descriptions to piece together a picture using
their knowledge of face structure, the imaging algorithms I develop
use our limited telescope data to guide us to a picture that also
looks like stuff in our universe. Using these algorithms,
we’re able to piece together pictures from this sparse, noisy data. So here I show a sample reconstruction
done using simulated data, when we pretend to point our telescopes to the black hole
in the center of our galaxy. Although this is just a simulation,
reconstruction such as this give us hope that we’ll soon be able to reliably take
the first image of a black hole and from it, determine
the size of its ring. Although I’d love to go on
about all the details of this algorithm, luckily for you, I don’t have the time. But I’d still like
to give you a brief idea of how we define
what our universe looks like, and how we use this to reconstruct
and verify our results. Since there are an infinite number
of possible images that perfectly explain
our telescope measurements, we have to choose
between them in some way. We do this by ranking the images based upon how likely they are
to be the black hole image, and then choosing the one
that’s most likely. So what do I mean by this exactly? Let’s say we were trying to make a model that told us how likely an image
were to appear on Facebook. We’d probably want the model to say it’s pretty unlikely that someone
would post this noise image on the left, and pretty likely that someone
would post a selfie like this one on the right. The image in the middle is blurry, so even though it’s more likely
we’d see it on Facebook compared to the noise image, it’s probably less likely we’d see it
compared to the selfie. But when it comes to images
from the black hole, we’re posed with a real conundrum:
we’ve never seen a black hole before. In that case, what is a likely
black hole image, and what should we assume
about the structure of black holes? We could try to use images
from simulations we’ve done, like the image of the black hole
from “Interstellar,” but if we did this,
it could cause some serious problems. What would happen
if Einstein’s theories didn’t hold? We’d still want to reconstruct
an accurate picture of what was going on. If we bake Einstein’s equations
too much into our algorithms, we’ll just end up seeing
what we expect to see. In other words,
we want to leave the option open for there being a giant elephant
at the center of our galaxy. (Laughter) Different types of images have
very distinct features. We can easily tell the difference
between black hole simulation images and images we take
every day here on Earth. We need a way to tell our algorithms
what images look like without imposing one type
of image’s features too much. One way we can try to get around this is by imposing the features
of different kinds of images and seeing how the type of image we assume
affects our reconstructions. If all images’ types produce
a very similar-looking image, then we can start to become more confident that the image assumptions we’re making
are not biasing this picture that much. This is a little bit like
giving the same description to three different sketch artists
from all around the world. If they all produce
a very similar-looking face, then we can start to become confident that they’re not imposing their own
cultural biases on the drawings. One way we can try to impose
different image features is by using pieces of existing images. So we take a large collection of images, and we break them down
into their little image patches. We then can treat each image patch
a little bit like pieces of a puzzle. And we use commonly seen puzzle pieces
to piece together an image that also fits our telescope measurements. Different types of images have
very distinctive sets of puzzle pieces. So what happens when we take the same data but we use different sets of puzzle pieces
to reconstruct the image? Let’s first start with black hole
image simulation puzzle pieces. OK, this looks reasonable. This looks like what we expect
a black hole to look like. But did we just get it because we just fed it little pieces
of black hole simulation images? Let’s try another set of puzzle pieces from astronomical, non-black hole objects. OK, we get a similar-looking image. And then how about pieces
from everyday images, like the images you take
with your own personal camera? Great, we see the same image. When we get the same image
from all different sets of puzzle pieces, then we can start to become more confident that the image assumptions we’re making aren’t biasing the final
image we get too much. Another thing we can do is take
the same set of puzzle pieces, such as the ones derived
from everyday images, and use them to reconstruct
many different kinds of source images. So in our simulations, we pretend a black hole looks like
astronomical non-black hole objects, as well as everyday images like
the elephant in the center of our galaxy. When the results of our algorithms
on the bottom look very similar to the simulation’s truth image on top, then we can start to become
more confident in our algorithms. And I really want to emphasize here that all of these pictures were created by piecing together little pieces
of everyday photographs, like you’d take with your own
personal camera. So an image of a black hole
we’ve never seen before may eventually be created by piecing
together pictures we see all the time of people, buildings,
trees, cats and dogs. Imaging ideas like this
will make it possible for us to take our very first pictures
of a black hole, and hopefully, verify
those famous theories on which scientists rely on a daily basis. But of course, getting
imaging ideas like this working would never have been possible
without the amazing team of researchers that I have the privilege to work with. It still amazes me that although I began this project
with no background in astrophysics, what we have achieved
through this unique collaboration could result in the very first
images of a black hole. But big projects like
the Event Horizon Telescope are successful due to all
the interdisciplinary expertise different people bring to the table. We’re a melting pot of astronomers, physicists, mathematicians and engineers. This is what will make it soon possible to achieve something
once thought impossible. I’d like to encourage all of you to go out and help push the boundaries of science, even if it may at first seem
as mysterious to you as a black hole. Thank you. (Applause)

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  1. Oh. So this is the woman that was one of 36 Programmers and she did about 4-6% of the code but get all the praise in the media. How typical.

  2. She did 6% of the work. Why is everyone lying about her contribution? A man did most of the work of which she is now taking credit.

  3. This young and energic lovely girl is actually a PhD student. 😭
    Oh god. Wht i've done in my life.

  4. she´s afraud, she added almost nothing to the research but stole the show with the prematurely released photo

  5. What I don’t get is, trump inherited a booming economy that took ten years to recover from bush’s 2008 recession due to deregulation. And trump takes all the credit. A PhD professional that have won many accolades, knowledgeable, lead a team, and her computer captured the first black hole in front of her. She wrote a PHD thesis on this an is an expert that made this possible. Yet people want to discredit her. Unbelievable

  6. Dr. Jessica Wade, physicist and advocate for diversity in STEM, about the backlash Bouman is facing: “The world’s largest scientific breakthroughs – like taking the first direct image of a black hole – can only happen when large, international, diverse, teams of scientists work together. For centuries, the people we have chosen to credit for those discoveries have been men.”

    “Of course Bouman will not have written all of the code, just like Englert and Higgs are not solely responsible for the discovery of the Higgs boson. Instead of discrediting the contributions of Bouman and the countless other women working on the Event Horizon Telescope, we should take a step back and remember she did not ask for this recognition – people all over the world just got tired of men being the only ones who are praised,” Wade said.

    In the discussion on Hacker News, and even in our own Facebook comment section, multiple users claim Bouman’s colleague Andrew Chael wrote over 850,000 lines of the 900,000 lines of code used to discover the black hole. Chael tweeted to her defense, saying that without Bouman and her contribution to the software, the project would never have been a success.

    (1/7) So apparently some (I hope very few) people online are using the fact that I am the primary developer of the eht-imaging software library to launch awful and sexist attacks on my colleague and friend Katie Bouman.

    Also I did not write "850,000 lines of code" — many of those "lines" tracked by github are in model files. There are about 68,000 lines in the current software, and I don't care how many of those I personally authored)

    Scientific discoveries and stories about men in the media are rarely believed to be hyperbole because the default societal perspective is that men make history. Now more awareness has been given to the contributions of overlooked women in STEM, people seem more eager to think Bouman is being celebrated solely because of her gender — when in fact, Bouman’s being celebrated for her revolutionary scientific discovery, alongside her team.

  7. Ha. I feel so sorry for the people that disliked this video. What a miserable outlook on life they must have.

  8. https://chrome.google.com/webstore/detail/threelly-ai-for-youtube/dfohlnjmjiipcppekkbhbabjbnikkibo

  9. She's just perfect – intelligent, amazing, beautiful, devoted to her work… and that smile <3

  10. 2017
    —Study and hard-work has finally paid off on
    2019–
    The Event Horizon Telescope has captured a photo of a supermassive black hole at the center of M87, a galaxy 54 million light years away.

  11. Wish could be on that stage on this time Shown to her that picture we took few days ago and watch her reaction

  12. This was such a mammoth scientific work, clearly proving that teamwork was essential without Doctor Bouman saying it! And there are some sexists down in the comment section taking offence on not seeing a man's face.

  13. What she is Describing is not science, it more like “Cargo Cult science”, practices that have the semblance of being scientific, but do not in fact follow the scientific method.
    They are taking this data and generating a image and then imposing a biased interpretation. See “Confirmation bias”.

  14. If she can take a picture of something 53 million light years away why can’t a take a picture of myself with it a foot away from myself

  15. Her algorithm found exactly what they told it to. Her pic two years before and it's spot on? Come on guys. I'm not saying they did it on purpose but they are scientists, question how you got it perfect the very first time!!!

  16. There’s no innovation here, it is just an application
    These images are called virtual images because they are processed and Created using data, in other words, it is not a photograph.
    In fact, since 1981 the process of creating pictures Using multiple radio telescope signals has been reported: CONTINUED TECHNOLOGICAL IMPROVEMENTS ASSIST VLBI EXPERIMENTS.-
    The rapid pace of recent astronomical discoveries has been largely due to the accelerated rate of technological advance. New techniques such as very long baseline radio interferometry and computer picture processing have improved the resolution or clarity of observations by several orders of magnitude.
    Creating a virtual picture and interpreting a picture are two different processes. Conclusion; Many of these techniques have been conceived by Others before, and goes back to the 1950s , in other words, these Young people are riding on the shoulders of giants.

  17. "How to take a picture of a black hole"
    Let Andrew Chael write 850,000 lines of code and literally take 100% of the credit but only do 10% of the work.

  18. I like how contradicting this "picture" is given that the black hole isn't really visible. It's more of an image really showing the outskirts of the black hole sucking up the light around it. Will give you a simple question as to why I don't consider it a picture. Can you take a picture of an invisible object?

  19. Anybody guide me. Does it mean the black hole looked like 55 million years ago not how it looks like now since it’s 55 million light years away?

  20. Youtube(2019):How to picture a blackhole
    " "(3025): DIY telescope to see a black hole

    Just being optimistic,sure the world end before 3000

  21. Katie Bouman, ladies and gentlemen, 2 years before making history. I'm proud to live in the same era as all these brilliant people who don't conform with mere ideas, but rather go out of their way to put them to the test.

  22. oh. so this a woman who contributed 6% of the work yet claimed 100% of the credit for that first black whole image. Nice. What a genius move.

  23. it's really cool that im watching this now after the photo was revealed, but sorta sad that i was directed here through the chicago style guide for citing websites

  24. Who is watching this after the public announcement of first picture of black hole based on her algorithm??

  25. Don't believe black holes exist, gravity is a very weak force. Black holes is just an interesting theory with no proof.

  26. CONCERNING THE POSSIBILITY OF GRAVITY REPELLING QUANTUM PARTICLES.

    WHERE IS ALL THAT UNKNOWN #SOMETHING THAT'S ACCELERATING #EXPANSION OF THE UNIVERSE #COMING #FROM??

    SO WITH THE ABOVE IN MIND , CONCERNING A BLACK HOLE.

    IS IT POSSIBLE THAT THE REASON FOR A #SPECIAL QUANTUM PARTICLE SEEMINGLY #EVERYWHERE #POSSIBLE #AT THE #EXACT#SAME #TIME IS BECAUSE THE PARTICLE IS #NOT #LIMITED BY SPEED AND THEREFORE GRAVITY IS #NOT #INTERACTING WITH THE PARTICLE TO LIMIT SPEED??

    IF SO , THEN WOULDN'T THAT MEAN THAT A QUANTUM PARTICLE AT A QUANTUM LEVEL SO #EXTRAORDINARY #SMALL , WOULD NOT INTERACT WITH GRAVITY SO GRAVITY WOULD NOT #EXIST THERE AT THAT SMALL #SCALE??

    AND IF SO , THEN IT WOULD POSSIBLY MEAN THAT THESE #SPECIAL SMALL QUANTUM PARTICLES #WOULD #REPEL #GRAVITY AND #ANYTHING #WITH #GRAVITY??
    PERHAPS THE REASON WHY A QUANTUM PARTICLE APPEARS , THEN DISAPPEARS IS BECAUSE FOR SOME REASON IT #STOPS , THEN #MOVES #SO #FAST THAT IT SEEMS TO DISAPPEAR!!!

    BUT THESE GRAVITY REPELLING PARTICLES ARE #NOT #CONNECTED TO ATOMS BUT RAW IN FORM WITHOUT BEING BOUND WITHIN A REALM OF ATOMS AND GRAVITY.

    IF SO ,THEN IMAGINE A BLACK HOLE'S #SINGULARITY OF #EQUAL EXTRAORDINARY #SMALLNESS WOULD #MEAN GRAVITY DOES NOT EXIST , THUS ALLOWING THE BIRTH OF THESE #SPECIAL #KIND OF SMALL #GRAVITY #REPELLING QUANTUM PARTICLES #TO #BE #BORN.
    THIS WOULD THEN #GIVE THE #BIG #BANG #UNDER #PRESSURE , OR A SERIES OF BIG BANGS DEPENDING ON THE NUMBER OF BLACK HOLES.
    IF THESE GRAVITY REPELLING PARTICLES ARE BORN OF A BLACK HOLE ,THEN THAT COULD #EXPLAIN #HOW ANY PARTICLES ESCAPE AND THE #SOURCE OF THE #ACCELERATING #EXPANSION OF UNIVERSE.
    I MEAN #WHERE IS THE SOURCE FOR THE EXPANSION COMING FROM??
    IF IT IS THESE GRAVITY REPELLING PARTICLES ESCAPING BLACK HOLE , THEN WOULDN'T THAT EVENTUALLY #EVAPORATE A BLACK HOLE??
    PERHAPS A SERIES OF BIG BANGS FROM DIFFERENT BLACK HOLES NOT #LONG #AFTER THE FIRST BIG BANG?

    SO IS THIS KIND OF PARTICLE RARE ON EARTH #SIMPLY BECAUSE IT REPELS ANY MATTER #WITH #GRAVITY?? JUST TO APPROACH IT WOULD BE DIFFICULT BECAUSE THE APPARATUS USED PLUS ENVIRONMENT WOULD HAVE GRAVITY.
    IF THOSE GRAVITY REPELLING PARTICLES WERE/ARE BEING MADE THEN THEIR COLLISIONS MAY #OVERCOME THEIR #REPULSIONS OF ONE ANOTHER AND MAY GO ON TO CREATE NEW PARTICLES THAT WOULD FORM SIMPLE ATOMS ,PERHAPS EVEN HEAVIER ELEMENTS-THEIR COLLISIONS AND FRICTION WOULD PERHAPS CREATE X-RAYS PERHAPS???

    SO WHAT CAME BEFORE 3 DIMENSIONAL SPACE?? 2 DIMENSIONAL SPACE- PERHAPS A BLACK HOLE ???

  27. Hey Katie quit stealing men's work.. You only contributed like a few lines of code and THATS IT. You didnt even invent the algorithm, because AGAIN, that was built by that German fellow. Quit stealing a hard working man's work! Don't stop faking the funk 😆

  28. لطفا بروز ترین یافته های علمی در رابطه با این همایش ونتیجه حاصل از ان از طریق تد اطلاع رسانی شود

  29. Listening to the explanation of what they are doing gives me a very strong and uncomfortable sensation like the black hole image isn't really as much of an image as it is what they think an image of a black hole should look like. And that they quite literally could have fed the computer with cat and dog images to get an end result like they did? Does she say literally say that? I'm not sure I understood right. In any case it's troublesome now that we've seen what the photo looks like how similar it is to their expectations.

  30. The first time I saw this I thought "how does this twelve-year-old girl know so much about black holes?!". Turns out she's actually a 30 year old adult 😂 Must be nice to be immortal!

  31. …Incommensurablement, à la reflexion directe, la toute première combine des prémices causales de l'existence du trou noir, je remonte…Étienne/Steve, Couronne de Dieu, en Haut-Lieu't, une répercussion ! "Radiophonique", ordré dans les bois ! Post-mortemique, hyperthymésique ! Métaphysique !…?https://m.youtube.com/watch?v=aKg1H70o0ts&t=131s

  32. media gives too much attention to these astronomers and their computational guys… Higgs Boson is important, first "photo" of a black hole…just OK.

  33. Zooming in past billions of stars?…it's easy just pretend they're not there?… similarly the furthest stars, galaxies and other celestial bodies of 14 billion light years away seem to have nothing in front of them?…their light is not distorted by gravity or anything else?… should I presume that the universe is really more empty than we are told?…or we are just lucky?..or smell the stench of a big fat rat?

  34. …Patrick De'Wilhelm Casque de Guerrier et de Volonté, de sa Corderie Royale de France Oléron is'land'land, LE PRIX DU VRAI DRAGON SAINT-GEORGES, Guillaume le Conquérant alias le Devil, le Millenium Reich, à l'âgisme, à la bosse (Notre-Dame), *Post-mortem et à la bulle, translation/transposition, *Grave/Graf'/Comte Jacques 1er et Duc Vin'cent du Roy'an ! – Tombe ! A'lié'nation ! Génique ! Attraction Universelle !? Microcosme à la base…Family Rocher and Étienne Couronne de Dieu…Antiroi/Antigène…limités, la distorsion magnétique à loeil bio'nique (faille , une vague de chaleur, ondulatoire, clef/porte/"téléportation", l'itération, le parallèlisme (<>_<>)…! L'Empyrée, la Puissance lyrique de la métaphysique, lol !
    Transcendance/Supraconscience ! https://m.youtube.com/watch?v=RJkdM5uf5wA

  35. …Blackhole/Breakthrough Prize ! Bravo ! Pour le Grave Jack…Infusion/Diffusion, une BAFF'-UNION, pour le Duc Vin'cent, une COUPOLE, Wilhelm Prinzip une ALLIANCE, Étienne, une COURONNE !?…BLACK ROY'AN DE SA CORDERIE ROYALE ! ASTROLOGY ! https://m.youtube.com/watch?v=vqxzwocZCZE

  36. Good. You please subscribe my channel as named as click mintaka and share it your all friends please…. Thanks to all

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