Hacker News new | past | comments | ask | show | jobs | submit login

I posted a comment 10 minutes ago and it got immediately downvoted into oblivion. Could you guys please tell me why it is such a bad question to ask? Thank you! Here it is:

Does it really count as an image of a black hole? Since no light is reflected by the black hole, all we see is light bend by the gravity of the black hole.

Haven't we seen that before? I have the strong feeling there have been photos of star constellations that seem distorted because of black holes.

A quick googling brings up this article from 2014 for example:


"Black hole bends light, space, time -- and NASA's NuSTAR can see it all unfold"

> Could you guys please tell me why it is such a bad question to ask?

Because it's nitpicking[0]. When scientists show you results of several years of work of many people, you effectively chose to ask question like "Is it really violet? Seems more purple to me". You don't contribute anything to discussion, but just want to sound smart-ass.

[0] https://www.urbandictionary.com/define.php?term=nitpicking

No, it's a legit question. Before I read this article I heard mention of a new picture of a black hole, and I was wondering how it was different from previous pictures.

My understanding now is that this is the first time we've observed one accurately enough to get a picture of the Einstein ring around a black hole. And even there, it's heavily reconstructed using machine learning, which I wouldn't call a "photo", more of a "AI artist rendition".

Any digital photo is a reconstruction. Consider all the pictures from the Hubble telescope: these techniques are a far more sophisticated version of the same kinds of techniques used to clean those up.


The link says nitpicking is "Looking for small or unimportant errors".

That is certainly not what I want to do.

The press is full of articles about this "First photo of a black hole". This seems to imply that it is somehow important. But so far, I fail to see what is important about it.

So my question still stands. I would really like to know in what sense this is the first image of a black hole. And if there is something we can learn from looking at it.

My first impression is "Yeah, it's round. I would have thought so." :)

Is anyone knowledgeable about the project calling it a "photo" (i.e., the term you used) or are they calling it (more accurately) an "image"?

My take in response to your original question is that it seems like nitpicking or armchair quarterbacking or something else related to that.

I'm always wary of succumbing to the "appeal to authority" fallacy, but this does seem like a case where all the experts and leading figures in a field are saying this is a big deal, and publishing a lot of info about it, so the right approach just seems to be to take the time to read/listen to what they're saying and learn, rather than posting simplistic skeptical questions in web forums.

If you didn't intend to come across that way, then perhaps rethink your question or the way you worded it.

Well, what would be a "first image"? There have been countless images depicting black holes since forever:


Since everybody seems to be looking for subterfuge in these comments, I'll try to answer the actual question you've asked.

The images in the google search link you supplied are all, without exception that i can see, artistic renderings of a black hole.

There are images of gravitational lensing [1] that show a basic distortion of light from gravity, but none of them reach the intensity of a black hole's 'event horizon'.

The body that we are seeing is at the center of the bright spot in this image [2], and is the source of the blue jet of material coming out. (I originally thought that jet was projected laterally, but in one of the two recent Veritasium videos on this topic he says it's actually heading almost straight at us and is 5000 light years long.) However, it's such an infinitessimally small part of the above image (about 1/10,000,000th the size) that we do not possess the optical resolving power to actually see it. For example, Hubble can resolve down to approximately .05 arcsecond. This image is approximately .00004 arcsecond. To get that resolving power they had to combine signals from radio telescopes all over the world using a technique called Very Long Baseline Interferometry. The contribution of Katie and her team is to extract a useful image from the petabyates of data that came from that exercise.

[1] - https://en.wikipedia.org/wiki/Gravitational_lens#/media/File...

[2] - https://upload.wikimedia.org/wikipedia/commons/3/39/M87_jet....

This is an image rendered from photons that had passed around the black hole, and travelled to Earth and been captured by a radio telescope that humans built.

It's the first time that's been done.

All the images in the DDG search are artistic constructions.

Edit: The thing that's so remarkable is that it does look like what scientists predicted it would look like, and thus some of those artistic representations are similar to what we're now seeing in this image.

It seems like a valid question. We're also told that a black hole isn't visible, and we're told that this image is reconstructed from sensor data. Whether or not it's really fair to consider it a "photograph" of a black hole boils down to exactly how much artistic license is taken in reconstructing the sensor data. Not knowing how much of this is artistic license, I'm willing to take the scientists at their word, but to ask the question doesn't seem like a nitpick.

EDIT: In Dr Bouman's TED talk, she notes that there are an infinite number of ways the sensor data could be constructed into an image, and that they were looking for a construction that looks like what they expect things in our universe look like. So, there's some ambiguity in the definition of "photograph"

Must admit, I feel kind of the same. It's also probably more of an artistic rendering than a photograph in the classical sense.

Humans can only see a tiny sliver of the enormous Electromagnetic spectrum. Just because it's not a photograph in visible light doesn't mean it's not our best rendering of EM data and what that would look like to us if it was in the visible spectrum.

We do the same thing with digital cameras, X-rays, MRI, etc.

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact