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Show HN: Physically accurate black hole you can put in your room

blackhole.plav.in

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Re: Show HN: Physically accurate black hole you can put in your room

#161

Post by andrecarini »

aplavin wrote: post #156
20k wrote: post #153

Earlier quoted context omitted.

Its frustrating because these issues are all fixable, and some of them are just bugs, but there's a mentality in this kind of science communication that ehh it doesn't matter because its just for the public. This does a real disservice to what people are trying to actually achieve in educating the public. Its also, unsurprisingly, a lot of hard work and validation to get from visualisation-grade, to physically accura…

Note that most of the points you raised are clearly not bugs – most notably, things like non-rotating black hole or colormap choice. At the very most, these can be considered missing features, but they don't affect correctness in any way.

You seem more interested in putting effort downplaying criticism and upholding the optics of "scientifically accurate thing from researcher in big name university" than actually putting effort on making the thing even better by using the amazing feedback you got...

Re: Show HN: Physically accurate black hole you can put in your room

#162

Post by agos »

aplavin wrote: post #154
gilrain wrote: post #124

Earlier quoted context omitted.

> completely arbitrary You agree that it isn’t “physically accurate”, then… but seem to argue that you shouldn’t be called out for the false title? It’s fair enough to be called clickbait when you really did score extra clicks with a slick falsehood, surely?

Arguing about colormap choice seems very strange to be – this is such a common practice in astronomy (and other fields!). The vast majority of images you see in published papers apply some arbitrarily-chosen colormap and color scheme. No matter if you look at observational or theory papers, it's very rare to find a real true-color image. And for a bunch of good reasons! The only difference here is that I don't show a…

it's common to use a colormap, but not using a perceptually uniform colormap in the year 2026 is quite a blunder

Re: Show HN: Physically accurate black hole you can put in your room

#163

Post by JadeNB »

gattr wrote: post #94
20k wrote: post #34

If anyone's interested in the accuracy, this is very 'visualisation grade' software. Its a bit of a pet peeve of mine that people present these sims as being very physically accurate, when they contain major inaccuracies, some of which are very obvious and/or deliberate. This one has some serious physical limitations I wouldn't mind at all if it didn't say that this was a *physically accurate* black hole specifically…

On a related note, there's an annoying mistake in one of the Fatalities in "Mortal Kombat 1": Liu Kang teleports with his opponent into outer space, summons a black hole with a snap of his fingers, and throws the poor sod in. But the accretion disc is red where it rotates towards camera, and blue where it rotates away!

Boy, I really hope somebody got fired for that blunder.

Re: Show HN: Physically accurate black hole you can put in your room

#164

Post by radicality »

7bit wrote: post #114
aplavin wrote: post #50

Earlier quoted context omitted.

> Its titled a "physically accurate black hole"! Please don't do this, if its intentionally not physically accurate and heavily simplified! It also doesn't exert the gravity an actually accurate black hole should :) And also, even on a phone with two cameras, they only cover a part of sphere – while a real black hole would bend light coming from all 4pi directions. Some simplification is generally required ("the map…

Always funny when people claim that scientific term apply to their software and then disregard any founded criticism in a non scientific way.

Now after reading the OPs responses and how defensive they are of some high quality constructive criticism, I don’t even want to go back and play more with the visualization.

Re: Show HN: Physically accurate black hole you can put in your room

#166

Post by KinetiNode »

20k wrote: post #34

If anyone's interested in the accuracy, this is very 'visualisation grade' software. Its a bit of a pet peeve of mine that people present these sims as being very physically accurate, when they contain major inaccuracies, some of which are very obvious and/or deliberate. This one has some serious physical limitations I wouldn't mind at all if it didn't say that this was a *physically accurate* black hole specifically…

but why was the picture taken of black hole have accretion disk yellow?

Re: Show HN: Physically accurate black hole you can put in your room

#167

Post by 7bit »

aplavin wrote: post #156
20k wrote: post #153

Earlier quoted context omitted.

Its frustrating because these issues are all fixable, and some of them are just bugs, but there's a mentality in this kind of science communication that ehh it doesn't matter because its just for the public. This does a real disservice to what people are trying to actually achieve in educating the public. Its also, unsurprisingly, a lot of hard work and validation to get from visualisation-grade, to physically accura…

Note that most of the points you raised are clearly not bugs – most notably, things like non-rotating black hole or colormap choice. At the very most, these can be considered missing features, but they don't affect correctness in any way.

You might wanna look up what correct means in a dictionary.

Re: Show HN: Physically accurate black hole you can put in your room

#168

Post by aplavin »

20k wrote: post #148
aplavin wrote: post #126

Earlier quoted context omitted.

Colormap/colorscale is generally considered an arbitrary choice in scientific plots or visualizations. Linear mapping of simulated emission brightness -> screen brightness could be a reasonable alternative mode, I agree – but it's weird to say that colormap choice makes it not accurate.

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 t…

> 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.

Re: Show HN: Physically accurate black hole you can put in your room

#169

Post by aplavin »

agos wrote: post #162
aplavin wrote: post #154

Earlier quoted context omitted.

Arguing about colormap choice seems very strange to be – this is such a common practice in astronomy (and other fields!). The vast majority of images you see in published papers apply some arbitrarily-chosen colormap and color scheme. No matter if you look at observational or theory papers, it's very rare to find a real true-color image. And for a bunch of good reasons! The only difference here is that I don't show a…

it's common to use a colormap, but not using a perceptually uniform colormap in the year 2026 is quite a blunder

> not using a perceptually uniform colormap in the year 2026 is quite a blunder

Then you are up for a big surprise if you browse through modern published papers :)

Re: Show HN: Physically accurate black hole you can put in your room

#170

Post by stackghost »

aplavin wrote: post #50
20k wrote: post #45

Earlier quoted context omitted.

>of course this is a simplified visualization Its titled a "physically accurate black hole"! Please don't do this, if its intentionally not physically accurate and heavily simplified! The general public on here don't know better, and it takes someone else with years of experience simulating black holes to dig through your code to show what you've simplified. There's like a few hundred people who have the right experi…

> Its titled a "physically accurate black hole"! Please don't do this, if its intentionally not physically accurate and heavily simplified! It also doesn't exert the gravity an actually accurate black hole should :) And also, even on a phone with two cameras, they only cover a part of sphere – while a real black hole would bend light coming from all 4pi directions. Some simplification is generally required ("the map…

>I don't see "simplified" as being opposite to "accurate".

Is it accurate to model a cow as a sphere?

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