What exactly is physically accurate here though? Because its not:
1. The relative brightness of different parts of the image
2. The colouring
3. The general relativistic effects of a black hole, other than the most basic disk warping effect
4. The relative colouring or brightness change from doppler
When you make a post about a physically accurate rendering, people usually expect it to be a decent representation of the underlying object in *some* capacity
There are of course constraints in terms of what the human eye can see and what we can portray - eg wanting to present alternative radio frequencies, highlighting different aspects of a black hole etc, which is why we make *specific* brightness and colouring map choices. That isn't a justification for making *arbitrary* choices in brightness and colouring map choices, because otherwise you could do sin(brightness * 1000) and call it physically accurate. In fact any output is an arbitrary colourmapping of a physically accurate black hole rasterisation under this definition, including a pure white square
Colour mapping and scale absolutely is very very much not an arbitrary choice, I linked elsewhere the event horizon telescope talking about this specific issue. People go to great lengths to put the work in to make physically accurate renderings, to convey accurately what you're looking at. I'm surprised to see you say that its considered arbitrary for renderings
There's a lot of room for doing visualisations to show off a specific element of a black hole, but the output here is near completely free of any physically accurate content. This is one of the more basic simulations I've seen - and that's before getting into the fact that it contains coding errors
> What exactly is physically accurate here though?
I'll assume this is a good faith question, hope it was intended like one. I view strong light bending as the key distinguishing property of a black hole, and something we are fairly certain about. This is reproduced accurately in all modes, up to the fundamental technical constraints of the browser environment. Gravitational redshift is another one, and it's also reflected.
Things like the precise matter configuration in the disk (and correspondingly its radial brightness profile) are much less well known, and are less fundamental for black holes as objects. This part is represented in a simplified way – thin disk, with a reasonable-shape analytic function defining radial emissivity distribution.
As for colormapping: I follow the by-far-dominant approach in scientific literature, where color mapping choice is completely unrelated to physical accuracy of the plotted observations or simulations. Having a preference for different color schemes is a matter of taste; suggesting a linear intensity->pixel mapping is a reasonable feature request, but far from a bug or inaccuracy.
So in your opinion, the primary thing that makes this a physically accurate simulation is that you've calculated the bending of light rays, and the structure, colouration and brightness of the accretion disk doesn't matter at all?
>As for colormapping: I follow the by-far-dominant approach in scientific literature, where color mapping choice is completely unrelated to physical accuracy of the plotted observations or simulations. Having a preference for different color schemes is a matter of taste; suggesting a linear intensity->pixel mapping is a reasonable feature request, but far from a bug or inaccuracy.
It is not true at all that this is the dominant approach in the literature, the event horizon telescope does not use this approach in their papers. I linked a comment from them elsewhere about this in a github PR
Specifically:
https://github.com/achael/eht-imaging/issues/85
>Unfortunately, vanilla afmhot does remain the current default in the eht-imaging library for historical reasons, but this could change soon. *Rest assured we thought of this issue and the paper images are indeed perceptually uniform!*
I would welcome an attempt for you to create a scale, that maps the output pixel brightness to the underlying physical luminance, which I think would show why the mapping is such a problem here from an accuracy perspective, but you're absolutely not correct that you're following the literature here. People are much more careful about presenting accurate data, and your approach would result in a correction being put out
>> I follow the by-far-dominant approach in scientific literature, where color mapping choice is completely unrelated to physical accuracy of the plotted observations or simulations.
> It is not true at all that this is the dominant approach in the literature
Just to clarify: you are saying that there are not a lot of images in literature rendered with a non-perceptually-uniform colormap (eg, any matplotlib colormap aside from the 5 uniform ones)? Or that there is only one correct way to choose colormap for a given image?
I'm saying that for black hole visualisation, the approach you're using is not necessarily standard in comparable papers. It would not be considered a physically accurate rendering no. People go to great pains to ensure that they're using the correct colour spaces and colour mappings to convey what they intend to convey, eg see the event horizon telescope papers which use perceptually uniform graphs
There is more than one choice as explained previously, it depends on what information you intend to communicate, whereas here the plot doesn't represent anything. I don't want to be rude, but this is plots 101, where the intensity does absolutely matter in your figures at minimum for renderings
I'd very highly recommend trying to create a scale for your work here to observe the problems with the approach in colouring and brightness, to check how it would work if you were to try and take one of these images and publish it in a paper, and compare it against other published intensity plots of black holes. People do make mistakes here, but its usually unintentional and a mixup due to not understanding gamma correction, which does indeed sometimes result in corrections