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First image of a black hole: a CNRS researcher had simulated it as early as 1979
- colordrops 5y agoUgh it must have been so satisfying to take all that science and data and generate an image like that in 1979.
- runjake 5y agoI wish they covered more technical detail into how and with what tools the image was generated. Anyone know?
- ColinHayhurst 5y agoSee the paper mentioned by @grafelic
- BitwiseFool 5y agoI've never understood the whole "First picture of a black hole" media hype. Point a telescope at a known black hole and capture the image. Is that not a picture of a black hole? I know that light cannot escape a black hole and when you 'see' one you are either seeing the accretion disk around it, or the lensing it does to stars behind it. Regardless, the black hole itself is in the image, no? I'm not saying the effort behind producing the image wasn't an achievement, just that the whole presentation felt very staged and inauthentic. Edit: Isn't the picture in question also just an image of the matter falling into the black hole? Per JPL: "to capture an image of the hot, glowing gas falling into a black hole" https://www.jpl.nasa.gov/edu/news/2019/4/19/how-scientists-captured-the-first-image-of-a-black-hole/ https://www.jpl.nasa.gov/edu/news/2019/4/19/how-scientists-c...
- NikolaeVarius 5y agoI'm sure that nobody ever thought of trying to do this.
- mdasen 5y agoThere’s a decent Netflix documentary on how difficult it was involving many teams across the world, software to interpret the data, etc. Black Holes: The Edge of All We Know
- atombender 5y agoWhat's new is that scientists were able to capture an image of its silhouette. Black holes, as you say, don't emit any light, so we can only see surrounding objects — the accretion disk and jets of hot gas. For comparison, the kinds of images we've been able to capture with Hubble look like this: https://fineartamerica.com/featured/core-and-optical-jet-of-galaxy-m87-nasaesastscihford-et-al.html https://fineartamerica.com/featured/core-and-optical-jet-of-....
- BitwiseFool 5y agoBut even in the image they generated, it is just the matter surrounding the black hole we see, right?
- atombender 5y agoWell, we can observe the absence of light, which (semantics aside) is also something you can see.
- wumpus 5y agoThis is usually called the "shadow" of the black hole. The press release we're discussing calls it that.
- deleted 5y ago[deleted]
- ISL 5y agoThe big challenge is that black holes are quite small. In order to say that you have "seen a black hole", it is necessary to rule out that you have seen something similar to a black hole but larger than what general-relativity would predict. The black hole at the center of M87 is large (about the size of our solar-system), but it is 55 million light-years away. If I computed things correctly, it subtends about 70 picoradians on the sky. That is about the same angular size as Alan Shepard's lunar golf ball as seen from Earth. So yes, if a black hole is at the center of a galaxy, its (non-)image will be in any image of a that galaxy. But, proving that you've seen a black hole means ruling out that it is some other kind of compact object that might be somewhat larger than a black hole. The only imaging-based way to do so is to image its event horizon, which requires resolving the angular size of the black hole itself.
- vishho 5y agoIt was because she was a girl. That is all there is to it. Insta-famous. Not that it is a bad thing to promote women in science, but also let us not pretend that the hype fuel was based on anything else.
- lgl 5y agoI can't downvote you but I'm sure you will very soon because this kind of idiotic and misogynistic comment is something that doesn't belong here, or anywhere really. If you think that an effort of hundreds of scientist and dozens of scientific institutions that took many years to bring us an unprecedented image of the universe was hyped or staged to make a single woman scientist insta-famous, you have largely misread the large majority of people that read hackernews. Nobody in their right mind will support this opinion, grow up.
- zalequin 5y agoYou’re either immature or brainwashed by the propaganda, because in the last decade the forceful advancement of diversity, social “justice” and cancel culture (to mention only a few things that are part of the same, larger, thing) have been more than clear - it’s become nauseating and tiresome. To pretend that we don’t promote women for the sake of promoting women is like saying we don’t hire asians, blacks, and jews because they’re asians, blacks, and jews. Of course we do.
- vishho 5y agoAll the downvoters were male. You are a male. And I am a girl BTW. You got so riled up, because deep down you know it is true. Even she knows the majority of the attention had to do with her gender. I am not sexist. I usually, like the question poser, don't see gender or race. But then it is pushed by activists (see Grace Hopper replacing lena.jpg) who want to have their cake and eat it too: they judge by gender and race, but you should judge without. I am done doing that. If you see Neil deGrass Teison added to the speaker list, you just know somewhere someone went: this panel lacks diversity. So Teison is de diversity pick, not the merrit pick. Just like Katie was highlighted, while using software written by men, who got lots of flack online, because clearly they were non-inclusive to women when building Scipy and Numpy for free.
- SiempreViernes 5y agoHave you ever wondered where your phone is, and some joker pulls out an image of Earth and says "here"? Well, you're that joker now buddy.
- BitwiseFool 5y agoHey buddy, I had a genuine question. No need to be a jerk about it. How is this https://en.wikipedia.org/wiki/Astrophysical_jet#/media/File:M87_jet.jpg https://en.wikipedia.org/wiki/Astrophysical_jet#/media/File:... not also an image of the black hole? This one too, https://en.wikipedia.org/wiki/File:V404Cyg_XRT_halo_fullsize.jpg https://en.wikipedia.org/wiki/File:V404Cyg_XRT_halo_fullsize... https://en.wikipedia.org/wiki/V404_Cygni https://en.wikipedia.org/wiki/V404_Cygni
- skykooler 5y agoIt's an image that contains the black home, but does not resolve the hole itself. Just like you can't really say a satellite photo is of an ant, even though there are definitely some within its borders.
- SiempreViernes 5y agoIt is or it is not for the exact same reason why a picture of the moon is, or is not, a picture of the moon lander that's still there.
- wumpus 5y agoThat's a pretty funny analogy! And a nicely accurate one. This movie (https://www.youtube.com/watch?v=7nMUqy8Rfp0 https://www.youtube.com/watch?v=7nMUqy8Rfp0) shows what M87* looks at various resolutions.
- terramex 5y agoYou can image many stars and black holes as point sources without issues. For M87 you can even capture its huge particle jet using telephoto lens, digital camera and small star tracker. This gives you their magnitudes, spectral lines, ability to detect planets passing in front of them etc. But if you want to resolve their image beyond point light it becomes very hard - there are hard physical limits on what size of aperture you need to resolve any detail. There are tricks to increase effective aperture by measuring phase of electromagnetic waves reaching antennas across the globe. It is called interferometry: https://en.wikipedia.org/wiki/Astronomical_interferometer https://en.wikipedia.org/wiki/Astronomical_interferometer Here is a list of the stars we have imaged beyond point source so far: https://en.wikipedia.org/wiki/List_of_stars_with_resolved_images https://en.wikipedia.org/wiki/List_of_stars_with_resolved_im... M87 is the first black hole imaged beyond point source.
- grafelic 5y agoI used the IBM 7040 mainframe of Paris-Meudon Observatory, an early transistor computer with punch card inputs. The machine generated isolines that were directly translatable as smooth curves using the drawing software available at the time. From Luminets personal recollections on black hole imaging: https://arxiv.org/pdf/1902.11196.pdf https://arxiv.org/pdf/1902.11196.pdf
- ColinHayhurst 5y agoGreat read, thank you. It goes on ... "The first step was to integrate the equations of light ray trajectories in Schwarzschild space-time and draw the isoradial curves (i.e. at constant radial distance from the black hole) of a thin disk around the black hole, as they would be seen by an observer above the disk's plane" .... "The final black and white "photographic" image was obtained from this pattern. Lacking of an appropriate drawing software, I had to create it by hand. Using numerical data from the computer, I drew directly on negative paper with pen and Indian ink,placing dots more densely where the simulation showed more light (a few thousands dots for the full plate). Next, I took the negative of my negative to get the positive, the black points becoming white and the white background becoming black. The result converged into the pleasantly organic, asymmetrical form reproduced in Figure 8, both visually engaging and scientifically revealing." I am feeling grateful to have started by scientific/engineering computing career one year later than the authors paper in 1980, and as it happens the first year without punched cards at my Univ.
- actually_a_dog 5y agoAmazing. Kip Thorne's simulation for the movie Interstellar took "a year of work by 30 people and thousands of computers." Of course, that was also an animated simulation with a high level of visual detail. https://www.wired.com/2014/10/astrophysics-interstellar-black-hole/ https://www.wired.com/2014/10/astrophysics-interstellar-blac...
- ffhhj 5y agoIn the comparison image M87's blackhole has an almost perfectly circular black spot, while in the simulated image the center is half a circle due to the disk. Is this caused by some missing effect in the calculations, the angle of the disk, or something else?
- wumpus 5y agoWe're looking down on M87* from one of its poles. The image from the paper is viewed close to the equator.
- yawaworht1978 5y agoI never understood this, do black holes have poles from any distance? I know if you're too close, everything gets distorted, but I would have thought they look the same from any direction or angle, never managed to grasp the concept. Maybe there is some 3d sim to explain this?
- wumpus 5y agoThe stuff falling onto the black hole has an orientation -- it forms an accretion disk at the "equator". If the black hole is spinning, it has poles. We expect all black holes to be spinning. This is a subtle change in the shadow itself, but... And if the accretion disk and black hole have misaligned poles, there should be a huge warp in the disk close to the black hole as the black hole frame-drags the accretion disk.
- ludwigschubert 5y agoIs the misalignment _necessary_? I always thought the hole got its rotation from the infalling matter.
- wumpus 5y agoOver billions of years, the angular momentum of the stuff falling in changes.
- raziel2701 5y agoIs the code freely available someplace? I found papers that talk about the math but I don't understand the math...
- sydthrowaway 5y agoThis needs to be reimplemented in JavaScript
- sydthrowaway 5y agoThis would be an amazing album cover.
- peter303 5y agoVery Long Baseline radio astronomy has been around for decades. One of its early accomplishments was the realtime observation of plate tectonics motion between telescopes. These days that is observed routinely with high resolution GPS. One EHT speaker I asked said an important advance was scaling up the VBLI procedure a thousand times from hundreds of megahertz to hundreds of gigahertz to achieve resolutions needed to image the three largest super massive black holes. This involves huge improvements across the entire system from the antenna receiver, clock resolution and petabyte data handling.
- wumpus 5y agoThe EHT can resolve the two super massive black holes which are the largest on the sky. The Milky Way's SMBH is a relatively small one, but it's close enough to make up for that.