Thank You Frontier for Fixing Black Hole Lensing, For Science!
- Thread starter Ziljan
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Why are you showing the light ray from the "eye" to the star and the virtual image of the star instead of the different paths form the star to the "eye" that result in virtual images of the star?
This is great stuff Ziljan 
I guess in FD's defence - they will almost certainly know everything that's wrong with BHs - but the challenge is accurately rendering lensing effects in realtime in a game engine that also has to be bothered with lots of other things outside of just the skybox etc.
I'm no graphics programmer any more - but I can't see how they can possibly do it anything approaching accurately without using pixel shaders and ray casting - something that's definitely doable in non-game scenarios, but when there are numerous other 3D artefacts to attend to I'm not sure is something that's realistically achievable on current hardware.
However - there are a lot of clever people involved here, and I'm sure it'll get better.
I guess in FD's defence - they will almost certainly know everything that's wrong with BHs - but the challenge is accurately rendering lensing effects in realtime in a game engine that also has to be bothered with lots of other things outside of just the skybox etc.
I'm no graphics programmer any more - but I can't see how they can possibly do it anything approaching accurately without using pixel shaders and ray casting - something that's definitely doable in non-game scenarios, but when there are numerous other 3D artefacts to attend to I'm not sure is something that's realistically achievable on current hardware.
However - there are a lot of clever people involved here, and I'm sure it'll get better.
The issue I am talking about in the OP is with the change in lensing when turning your head or rotating your ship when parked in front of a black hole.
There are no "pictures" of this because pictures are static and don't move rotate in 3D. There are also no videos of the effect of approaching a black hole in the first person perspective either. Elite is the first to attempt this, afaik. There are videos of black hole simulations from static perspectives. And black hole fly bys. But nothing with a rotating first person perspective.
This is is why I made the diagrams in the OP to help illustrate the issue in a simplified 2-D image. If you have any questions, please refer to the OP and ask me. I'll be happy to do my best to explain it without using math, if possible.
Btw, as I said in the OP, screen shots are somewhat accurate in the static lensing effect, except for the way they turn Einstein Rings into sphincter-like puckers, lol. Light would not bend in lobes, but rather in rings.
I am no astronomy expert but isn't a black hole a singularity, thus infinitely small? So shouldn't it be correct that our ships are much bigger than the black hole (as their size is >0)? Shouldn't the black hole better be represented by a dot instead of a circle in your drawings?
If we're talking about the black hole itself that is, not about its Schwarzschild radius.
Knowing Braben's passion for astronomy, I am 100% sure that he is well aware of this (and some other) issues. I also suppose it's the limitations of his Cobra engine that got in the way.
This is great stuff Ziljan
I'm no graphics programmer any more - but I can't see how they can possibly do it anything approaching accurately without using pixel shaders and ray casting - something that's definitely doable in non-game scenarios, but when there are numerous other 3D artefacts to attend to I'm not sure is something that's realistically achievable on current hardware.
However - there are a lot of clever people involved here, and I'm sure it'll get better.
It sounds complicated but the solution is really simple, instead of recalculating the effect for the direction your head is facing + the distance from the black hole, they could simply just pretend that a 2nd ghost perspective (at your exact location) is always looking directly at the black hole. Then they could attach the lens effect to to this ghost perspective. In effect this would massively simplify the number of calculations done to create the lensing effect because it would ALWAYS be in the same direction regardless of where you look.
In other words, this corrected solution involves only 2 variables: radius and azimuth from the black hole. Whereas the current lens effect requires, radius, azimuth, and a second calculation for 2 more spherical coordinates based on your POV direction. If the POV calculation is removed, they can use the same current effect, but with half the math.!
And since the false POV effect is "twitchy" anyway, the cleaner lensing effect would look a lot smoother and lovelier both in the cockpit and in the debug camera. Giving the Black Holes a more refined and stately appearance that suites their size and stature, and of course making for much better YouTube videos.
None of your pictures are accurate models of an optical lense effect.
You missed more than half of the lightpoints.
This picture is also quite oversimplified, since the distance of the obeserver to the lense is the same as the distance of the object he's observing.
I'm not sure if the ED model of the black hole is accurate or not, but this would be the optical principle to apply:
You missed more than half of the lightpoints.
This picture is also quite oversimplified, since the distance of the obeserver to the lense is the same as the distance of the object he's observing.
I'm not sure if the ED model of the black hole is accurate or not, but this would be the optical principle to apply:
Light cannot pass through the event horizon and come out again. So no. All light paths that pass inside the white circle lead back to the singularity.
If you want to check the scale, get close enough to for the head jiggle to impact the lensing and check your distance to the black hole. It's typically measured in light seconds aka hundreds of thousands of miles. Much much bigger than any Asp I've ever seen.
In effect, rotating your ship in ED near a black is like accessing bigger orbits by turning your head. It's magic. Not science.
The size of the observer or even the object that holds him in place should be irrelevant, since the light emitted is focused by the lense into a single point (ideally) anyways (somewhere on our retina or the chip of a camera).
It's more the relation between the light emitting object to the lens and from there to the observer that should determin the amount of movement of the observed object you see .. if I remember that old stuff correctly.
It's more the relation between the light emitting object to the lens and from there to the observer that should determin the amount of movement of the observed object you see .. if I remember that old stuff correctly.
Unlike galaxies and nebulae, Stars are mathematical point sources. And the other "half" of the paths of light either travel through the event horizon (never to be seen again) or they never focus at your location from the other side of the black hole. The only way to get light lensed from both sides of the black hole from the same distant source is if the object is directly behind the black hole. This is what is known as an Einstein Ring
Good question though. But just to be clear, real black holes don't act like optical lenses. They can't focus at a point, only along a radial line. Which was kind of the the whole point of the OP.
If black holes could focus light at a single point like a lens, then that would mean that gravity increased with distance! Lol. I hope we can all agree that gravity decreases with distances?
. Otherwise Issac Newton is going to be pretty upset.
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I'm sincerely missing the -rep button due this sort of comments
@OP: there's bits and pieces in this that could well go into the Suggestions forum
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Unlike galaxies and nebulae, Stars are mathematical point sources. And the other "half" of the paths of light either travel through the event horizon (never to be seen again) or they never focus at your location from the other side of the black hole. The only way to get light lensed from both sides of the black hole from the same distant source is if the object is directly behind the black hole. This is what is known as an Einstein Ring
Good question though. But just to be clear, real black holes don't act like optical lenses. They can't focus at a point, only along a radial line. Which was kind of the the whole point of the OP.
If black holes could focus light at a single point like a lens, then that would mean that gravity increased with distance! Lol. I hope we can all agree that gravity decreases with distances?
Mathematically, every lense should act like a lense. Otherwise it wouldn't be a lense. (or someone please give me the "for dummy" article regarding gravitational lenses .. the Wikipedia might be too shallow .. that's the simulated gravitational lense effect from there: https://upload.wikimedia.org/wikipedia/commons/0/03/Black_hole_lensing_web.gif which looks pretty much like the ED one, but they don't give any parameters of the simulation - distance, size, speed - so it's a bit pointless <- pun intended)
If gravitation would increase with distance, the light would get "pulled out harder" -> concave lens.
Gravitation increses with proximity, the light gets "pulled in harder" -> convex (spherical actually, most optical lenses are aspherical) lens with event horizon (that's the difference with an optical lense, if the medium would be thick enough to create such change of path as the gravitational singularity, no light would probably pass it, so we would see an all black center, not the event horizon ring).
(and I'm not arguing, I'm more or less talking to myself, trying to see how much of that stuff I still remember .. and I was always better at quantum mechanics than optics or thermodynamics or the more classical things .. but so long ago
)(and it's actually a videogame, where such topics are part of the universe, which is part of the whole magic
.. I wouldn't really know or be able to calculate if a change of inches or meters of the observer would be sufficient to cause so much movement in the effect of a black hole .. if there are black holes http://www.nature.com/news/stephen-...k-holes-1.14583?wafflebotContextId=1218346891 .. and I must admit that I always had issues with that mathematical concept of "infinity" .. doesn't compute)
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As it happens, The latest two articles on Centauri Dreams touch upon gravitational lensing and also explain this - graviational lenses don't have a point of focus, but a line that starts at a minimum distance (the more massive, the shorter that distance) and stretches to infinity.
http://www.centauri-dreams.org/?p=35486
http://www.centauri-dreams.org/?p=35498
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Boomer,
Lensing just means bending the path of light. Different lenses behave differently. There are near infinite variations. Not all lenses can focus light at a single point. For instance, concave lenses will actually scatter light in a wide arc.
Real world gravitational lensing acts more like the base of a wine glass, or like a Victorian era semi circle speculum telescope mirror. Very inaccurate and blurry focus.
The point of the OP is that if you were a microscopic amoeba floating near any kind of unfocused lens and you rotated your little amoeba head, you would not see a different bending of light through the lens. You'd be too small and would only have access to whatever photons were passing through you. They would seem like straight lines. Much in the same way that the earth looks flat when you are a human sized person standing on it.
Lensing just means bending the path of light. Different lenses behave differently. There are near infinite variations. Not all lenses can focus light at a single point. For instance, concave lenses will actually scatter light in a wide arc.
Real world gravitational lensing acts more like the base of a wine glass, or like a Victorian era semi circle speculum telescope mirror. Very inaccurate and blurry focus.
The point of the OP is that if you were a microscopic amoeba floating near any kind of unfocused lens and you rotated your little amoeba head, you would not see a different bending of light through the lens. You'd be too small and would only have access to whatever photons were passing through you. They would seem like straight lines. Much in the same way that the earth looks flat when you are a human sized person standing on it.
The thing in ED is you see such effects just by turning your head, which in reality it wouldn't. Moving at great speed in supercruise past a black hole should indeed (and does) produce a similar effect in the game.
That's the thesis.
I miss the math that takes your distance to the black hole, the size of the black hole and it's gravitational lense and the point light source's distance to the black hole into account. (those FOCAL articles are quite intersting.. I can follow with just a slight headache
)Well, supercruise is already implemented against all current scientific knowledge. You fly faster than light - that should (or should not?) produce quite different imagery for our weak monkey eyes. As far as I can tell, there's not the slightest difference between <1c and >1c.
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Whatever it looks like I would like more danger accredited to black holes in game. They truly are without teeth. I want a real event horizon that messes up your FSD and spaghettifies your lovely Asp if you get too near. For me that would add excitement and peril that would be hard to resist. I would be out there looking for black holes to play with if I weren't so disappointed with how they are represented in game.
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