Thunderbolts Forum

'14-03-15, 00:14 Sain84	Re: Relativity CharlesChandler wrote: What is the dispersion over that frequency range for a mirage — say, for example, one that can refract the light 5 degrees? No idea, there are no papers on such a topic that I can find. As I said people work away from the horizon.
'14-03-15, 02:42 CharlesChandler	Re: Relativity Sain84 wrote: CharlesChandler wrote: What is the dispersion over that frequency range for a mirage — say, for example, one that can refract the light 5 degrees? No idea, there are no papers on such a topic that I can find. As I said people work away from the horizon. Right. So when you said, "Nothing known can do that" (in reference to deflection that is not differentiated per wavelength), that was just arguing from ignorance? In order for the argument to be worth more than that, somebody has to actually check that mirages are, in fact, refractions, with all of the characteristics of a lens, including chromatic dispersion, and not some fundamentally different mechanism. The QM explanation for mirages certainly doesn't necessitate that they would behave as prisms. As concerns green flashes, I'm actually not convinced that they're chromatic dispersions due to refraction from the mirage effect. First, there is almost no deflection — the effect is right there on the limb of the Sun, not a rainbow that is offset from the light source. This is significant in that I have shown an example of a mirage that deflected the light several degrees, with no dispersion. If a couple of minutes of deflection shows dispersion, but a couple of degrees of deflection does not, something is seriously wrong with somebody's assumptions. Second, have a look at this, and tell me that it is simple refraction. How can there be a blob of yellow above a green flash? And how come the upper blob doesn't have its own green fringe? I think that refraction might actually be just a convenient, but not necessarily accurate, description of mirages. I know you think that I'm just being ornery, but the supposed gravitational lensing was the first "proof" of GR, and continues to be the first thing cited whenever anyone challenges GR. You'd think that after 80 years, the proof would have been formalized, and double-checked, and there wouldn't be anything about it left to chance, considering the weight that is put on GR. In fact, it should be THE textbook example of how to do good science with the new physics. So when questioned on gravitational lensing, the GR proponent should be able to lay out how the known factors were quantified, and the remaining discrepancy therefore could only be attributed to the new physics. As it is, GR proponents don't even understand why, or how, you would ever question anything. That tells me that they don't even understand good scientific methods. Somebody told them that gravity deflects photons; the proper method for arriving at such a conclusion was not specified; they didn't ask; so they simply accepted what they were told. That isn't science. To make a reasonable case for gravitational lensing, you have to show me where somebody quantified the characteristics of mirages, to the accuracy necessary to rule them out as a cause for the observed deflection. If you cannot, gravitational lensing must surrender to the forces of Occam.
'14-03-15, 19:58 Sain84	Re: Relativity CharlesChandler wrote: Right. So when you said, "Nothing known can do that" (in reference to deflection that is not differentiated per wavelength), that was just arguing from ignorance? No, it's exactly like your post on mass conservation. There are lots of experiments showing materials and the atmosphere are dispersive. There are no known materials which are non-dispersive over such a huge wavelength range. Until someone shows me something otherwise this will continue to be true. It's not an argument from ignorance, it's a fact. We know atmospheric refraction is dispersive from observations of stars. The fact that no one has carried out your very specific experiment does not change that. How do we know mirages come from refraction? As I have shown you distortions like that can be calculated, for example the Sun. That shows refraction is consistent with the observation, we can do no better. What "QM interpretation" allows for a non-dispersive medium over such a wavelength range? CharlesChandler wrote: As concerns green flashes, I'm actually not convinced that they're chromatic dispersions due to refraction from the mirage effect. First, there is almost no deflection — the effect is right there on the limb of the Sun, not a rainbow that is offset from the light source. This is significant in that I have shown an example of a mirage that deflected the light several degrees, with no dispersion. If a couple of minutes of deflection shows dispersion, but a couple of degrees of deflection does not, something is seriously wrong with somebody's assumptions. Second, have a look at this, and tell me that it is simple refraction. How can there be a blob of yellow above a green flash? And how come the upper blob doesn't have its own green fringe? I think that refraction might actually be just a convenient, but not necessarily accurate, description of mirages. As I have explained you don't see a rainbow because of scattering which removes the bluer light. The red light is refracted lower and this leaves the green light. As I have explained with the example of lenses geometry is important not just the level of deflection. What you have not shown me is any system that can do the same from radio to optical. I don't know what orange blob you're talking about. Just like a mirage random pockets of hot air can distort the image causing multiple lensed images. The paper I quoted earlier actually simulated a green flash using refraction. GR has been double checked, the lensing findings are consistent with it. What you are proposing is another hypothesis entirely for which you need some mystery material which conveniently hangs around mass proportional to that mass. I was under the impression you people had a problem with ad hoc hypotheses like this. CharlesChandler wrote: Somebody told them that gravity deflects photons; the proper method for arriving at such a conclusion was not specified; they didn't ask; so they simply accepted what they were told. Then you misunderstand the process of science. You cannot prove gravity bends light, you can only prove your observations are consistent with your theory. Most people who work on GR are quite aware of the derivation and why it occurs. You don't need to understand the fundamental nature of gravity to test it, just like Maxwell didn't understand the nature of electromagnetism. CharlesChandler wrote: To make a reasonable case for gravitational lensing, you have to show me where somebody quantified the characteristics of mirages, to the accuracy necessary to rule them out as a cause for the observed deflection. If you cannot, gravitational lensing must surrender to the forces of Occam. I have made a case for gravitational lensing. You have suggested another hypothesis which is something else entirely. No one has done your experiment because nobody thinks it's worth doing, if you think otherwise that's your job. If that's what it would take for you to be convinced then you are welcome to your opinion. Let's consider Occam's Razor for 2 minutes. It says if you have two models with equal power to explain the data the one with fewer free parameters is the favoured one. It does not say one is wrong. Firstly your model hasn't been shown to have equal explanatory power, so Occam's Razor doesn't apply. Secondly your model requires the assumption that such a material exists and would need to assume several parameters needed to describe it's distribution and the reason it sticks to mass. Gravitational lensing on the other hand requires only the basic postulates of general relativity which is the equivalence principle and some conservation laws, the mass of the Sun can be fund by other means. Lastly GR explains this observation, and shaprio delay another result which has been measured in the solar system.
'14-03-15, 21:53 CharlesChandler	Re: Relativity Sain84 wrote: CharlesChandler wrote: Right. So when you said, "Nothing known can do that" (in reference to deflection that is not differentiated per wavelength), that was just arguing from ignorance? No, it's exactly like your post on mass conservation. There are lots of experiments showing materials and the atmosphere are dispersive. There are no known materials which are non-dispersive over such a huge wavelength range. Until someone shows me something otherwise this will continue to be true. It's not an argument from ignorance, it's a fact. [...] I have made a case for gravitational lensing. You have suggested another hypothesis which is something else entirely. No one has done your experiment because nobody thinks it's worth doing, if you think otherwise that's your job. If that's what it would take for you to be convinced then you are welcome to your opinion. You can't be serious, can you? This is getting funny. Thanks for that. Wikipedia wrote: Argument from ignorance (Latin: argumentum ad ignorantiam), also known as appeal to ignorance (in which ignorance stands for "lack of evidence to the contrary"), is a fallacy in informal logic. It asserts that a proposition is true because it has not yet been proven false (or vice versa). This represents a type of false dichotomy in that it excludes a third option, which is that there is insufficient investigation and therefore insufficient information to prove the proposition satisfactorily to be either true or false. In debates, appeals to ignorance are sometimes used to shift the burden of proof. You must have already read that, except you thought that it was instructions for the proper way to do a debate!!! It is certainly a fact that you don't know of anything that can deflect light without chromatic dispersion. But you're definitely asserting that the atmosphere is dispersive, because you don't know of anything that isn't. And yet it seems that nobody has bothered to check to see if mirages, capable of far more deflection than sunsets, are dispersive, when visually, there isn't any evidence that they are, and visually, there is evidence that sunsets are. Your mistake is to not leave open the possibility that mirages deflect light without dispersion. As concerns sunsets over the ocean, I know of something that can cause dispersion, other than density gradients in the air, and that is expected over the ocean: water aerosols. That would explain why, with just a couple of minutes of deflection, we (sometimes) see green flashes, while in dry air out in the desert, we see several degrees of deflection, with no dispersion (determined visually in both cases). Sain84 wrote: How do we know mirages come from refraction? As I have shown you distortions like that can be calculated, for example the Sun. So why can't we "calculate" non-dispersion, for example in a mirage out in the desert, with the same formulas? Oops, because they would predict more dispersion, and what we see is none. So those calcs wouldn't be worth running. Sain84 wrote: That shows refraction is consistent with the observation, we can do no better. Speak for yourself. Sain84 wrote: What "QM interpretation" allows for a non-dispersive medium over such a wavelength range? http://www.scientificamerican.com/artic ... -a-mirage/ To understand how a mirage forms, one must first understand how light travels through air. If the air is all the same temperature--cold or hot--light travels through it in a straight line. If a steady temperature gradient exists, however, light will follow a curved path toward the cooler air. The standard freshman physics explanation for this phenomenon is that cold air has a higher index of refraction than warm air does. As a result, photons (particles of light) travel through hot air faster than they can through cold air because the hot air is less dense. The quantum electrodynamics explanation is that photons always take the path of minimum time when traveling from one point to another. In order to get from one point to another in a minimum time, photons will take "shortcuts" even though the length of the path is curved and it covers a longer distance than the direct route. Mirages are a direct result of photons taking the path of minimum time in vertical temperature gradients. Ideal conditions for a mirage are still air on a hot, sunny day over a flat surface that will absorb the sun's energy and become quite hot. When these conditions exist, the air closest to the surface is hottest and least dense and the air density gradually increases with height. Incoming photons take a curved path from the sky to the viewer's eye. The illusion comes from the fact that quantum electrodynamics is not intuitive and the human brain assumes that light travels in a straight line. A viewer looking at, say, the road ahead on a hot, still, day will see the sky because photons from the sky are taking the curved path that minimizes the time taken. The brain interprets this as water on the road because water would reflect light from the sky in much the same way that a vertical temperature gradient does. I love that they said that the illusion is the product of the counter-intuitive nature of the explanation!!! Anyway, photons knowing to steer around high densities so that they can get to where they are going faster makes no mention of one wavelength being more adept at it than another. Sain84 wrote: The paper I quoted earlier actually simulated a green flash using refraction. Ooooooooooooooooo... Sain84 wrote: GR has been double checked... Against what? Sain84 wrote: What you are proposing is another hypothesis entirely for which you need some mystery material which conveniently hangs around mass proportional to that mass. Whaaaaaa... Who's talking about a "mystery material"???? I'm saying that AIR causes mirages. You can't believe that a density gradient in air can deflect photons without dispersion, because nothing else that you know can do this, so you think that I cannot possibly be talking about air. But yes — I'm talking about AIR!!! And no, I don't invent mystery materials when things don't go my way — only mainstream scientists are licensed to do that!!! Sain84 wrote: I was under the impression you people had a problem with ad hoc hypotheses like this. Mirages have been observed since ancient times. That's what you call "ad hoc"???? Sain84 wrote: Let's consider Occam's Razor for 2 minutes. It says if you have two models with equal power to explain the data the one with fewer free parameters is the favoured one. It does not say one is wrong. Firstly your model hasn't been shown to have equal explanatory power, so Occam's Razor doesn't apply. Sain84 wrote: Secondly your model requires the assumption that such a material exists and would need to assume several parameters needed to describe it's distribution and the reason it sticks to mass. No, I don't have to assume that air exists, nor why it sticks to mass. Sain84 wrote: No one has done your experiment because nobody thinks it's worth doing... As easy as it would be to do this, I am simply staggered by the fact that nobody has ever checked for deflection without chromatic dispersion in mirages, considering that gravitational lensing is one of the cornerstones of GR. It speaks volumes about the absence of rigor in the GR camp.
'14-03-15, 23:28 Sain84	Re: Relativity CharlesChandler wrote: It is certainly a fact that you don't know of anything that can deflect light without chromatic dispersion. But you're definitely asserting that the atmosphere is dispersive, because you don't know of anything that isn't. And yet it seems that nobody has bothered to check to see if mirages, capable of far more deflection than sunsets, are dispersive, when visually, there isn't any evidence that they are, and visually, there is evidence that sunsets are. Your mistake is to not leave open the possibility that mirages deflect light without dispersion. As concerns sunsets over the ocean, I know of something that can cause dispersion, other than density gradients in the air, and that is expected over the ocean: water aerosols. That would explain why, with just a couple of minutes of deflection, we (sometimes) see green flashes, while in dry air out in the desert, we see several degrees of deflection, with no dispersion (determined visually in both cases). No. Quote what I actually said. "Nothing known can do that" which is true until there is a counter example. I am not claiming to know there is nothing that does this but I do know there is nothing known that does. This is not an argument from ignorance, it is a fact. The atmosphere is disperisive, I have shown evidence of that. As I have said before, the fact that mirages do not have strong dispersion is not in conflict with anything. Simple cameras often don't show dispersion until properly analysis. CharlesChandler wrote: So why can't we "calculate" non-dispersion, for example in a mirage out in the desert, with the same formulas? Oops, because they would predict more dispersion, and what we see is none. So those calcs wouldn't be worth running. We could calculate it but mirages are specifically caused by perturbations to the equilibrium of the atmosphere rather than refraction above the horizon where stratification is dominant and perturbations along the line of slight are less significant. You could calculate it but you would need lots of information. If you haven't done the calculation how do you know what you would see? You're guessing. CharlesChandler wrote: Sain84 wrote: What "QM interpretation" allows for a non-dispersive medium over such a wavelength range? http://www.scientificamerican.com/artic ... -a-mirage/ That doesn't answer my question. The same principle, the principle of least time governs all of optics, including prisms. The article doesn't mention wavelength dependence but that doesn't mean it doesn't exist. Again I ask what theory allows for refraction over such a frequency band without dispersion. CharlesChandler wrote: Against what? Observations. CharlesChandler wrote: Who's talking about a "mystery material"???? I'm saying that AIR causes mirages. You can't believe that a density gradient in air can deflect photons without dispersion, because nothing else that you know can do this, so you think that I cannot possibly be talking about air. But yes — I'm talking about AIR!!! And no, I don't invent mystery materials when things don't go my way — only mainstream scientists are licensed to do that!!! No, we're talking about gravitational lensing, not mirages. If you want to explain lensing observations with refraction you need a mystery material in space which is non-dispersive and well arranged.
'14-03-16, 01:06 CharlesChandler	Re: Relativity Sain84 wrote: "Nothing known can do that" which is true until there is a counter example. If there is a counter example, you'll refuse to acknowledge it. Sain84 wrote: We could calculate it but mirages are specifically caused by perturbations to the equilibrium of the atmosphere rather than refraction above the horizon where stratification is dominant and perturbations along the line of slight are less significant. Oh, OK, so now you understand mirages? Can you explain how a stable temperature inversion on that scale can exist, to produce an inferior mirage? Given a surface layer around 30 degrees C, topped by another layer that is typically 20 degrees C, why isn't the hotter air positively buoyant? Doesn't that break all of the laws of thermodynamics? Sain84 wrote: The article doesn't mention wavelength dependence but that doesn't mean it doesn't exist. Well, if QM explains it, I don't understand it, and that's an argument from fact! Sain84 wrote: Again I ask what theory allows for refraction over such a frequency band without dispersion. I never said that there was an existing explanation.
'14-03-16, 15:02 moonkoon	Re: Relativity To whom it may concern. Like others, I'm not happy with the gravitational lensing idea. One of the things that puzzles me..., light is an electro-magnetic phenomena and as such it just adds to the local electromagnetic environment, so how does gravity distinguish it when it is just an oscillation in a bigger buzz? Or does gravity shape the whole em scene? Hard to believe that when you consider the enormous difference in relative strengths of the two fields, em and gravity. Another concern is the small number of so-called lensing occurrences, why don't we see more of them? What's wrong with considering the possibility of the presence of 'atmospheres' surrounding objects up there in starland? And what about a role for reflection in these mysterious regions? Maybe Plato was right. P.S. I have looked at quite a few lensing pictures, I see plenty of what look like blue time-lapse streaks but I've yet to find a complete Einstein ring. Have any been spotted?
'14-03-16, 17:29 Sain84	Re: Relativity CharlesChandler wrote: If there is a counter example, you'll refuse to acknowledge it. How about we confine the argument to the evidence that actually exists. CharlesChandler wrote: Oh, OK, so now you understand mirages? Can you explain how a stable temperature inversion on that scale can exist, to produce an inferior mirage? Given a surface layer around 30 degrees C, topped by another layer that is typically 20 degrees C, why isn't the hotter air positively buoyant? Doesn't that break all of the laws of thermodynamics? Note, that's not what I said. I said if you had all the information, you could simulate it. That doesn't break the laws of thermodynamics. The ground layer is heated and that energy diffuses largely with convection but in the steady state solution the lowest layers can continue to be the warmest. It depends on the strength of diffusion, in this case convection. It's not that convection is shut off, warmer air is buoyant. CharlesChandler wrote: Sain84 wrote: Again I ask what theory allows for refraction over such a frequency band without dispersion. I never said that there was an existing explanation. You specifically said the QM interpretation didn't require dispersion but I'll drop that. So what we have is no theoretical or experimental basis for such a material existing. Invoking such a material to explain lensing would be quite an assumption.
'14-03-16, 20:05 CharlesChandler	Re: Relativity Sain84 wrote: CharlesChandler wrote: If there is a counter example, you'll refuse to acknowledge it. How about we confine the argument to the evidence that actually exists. Please define what you mean by the word "exists"! Does this "exist"... http://ctein.com/STS1_in_Desert.jpg It doesn't suit your view, so for you, it just doesn't exist, and as such, it isn't a legitimate counter example!!!! Sain84 wrote: The ground layer is heated and that energy diffuses largely with convection but in the steady state solution the lowest layers can continue to be the warmest. It depends on the strength of diffusion, in this case convection. It's not that convection is shut off, warmer air is buoyant. Oh, OK, so you don't actually know much about inferior mirages. Well let me fill you in. If you simulate a burner that is 10 degrees C warmer that the overlying air, at STP, you quickly get Benard cells. Roughly speaking, they'll be something like 30 m wide, and about 50 m tall, with convection running at a couple m/s. Not exactly a gale force wind, but enough to be noticeable. As the air skims along the burner, it will pick up just a couple of degrees C, but that's enough to drive the convection. But in the conditions in which inferior mirages form, there is no convection — absolutely none at all. I could refer you to literature on this, but you could also observe it in this image: http://ctein.com/STS1_in_Desert.jpg Could such a near-perfect mirror image be produced with light traveling through air at a variety of temperatures, going in and out of at least a couple of those Benard cells? No. So the question is: why isn't there any convection at all? Note that the thermodynamic question here would typically be considered outside the scope of a discussion of relativity. But I tend to think that since scientists don't actually understand inferior mirages, they start with a gibberish framework. Then they proceed to make more mistakes past that point. Part of the problem is that they started with something they didn't actually understand. So I traced it all of the way back, so that I'd be standing on terra firma the whole way through. And there's more to inferior mirages than just a burner that produces air that's hotter while it's up against the burner. Hint: stable inferior mirages only occur over non-conductive surfaces, such as dry sand, or asphalt (which works better because it's generally flatter, and the darker color absorbs more photons, and therefore heats up faster). Now do you understand why there is no convection, even though all of the simulators say that there simply has to be? Hot air rises, right? If it doesn't, there has to be a force offsetting the buoyancy. It has something to do with the absence of conductivity in the burner...
'14-03-17, 21:14 Sain84	Re: Relativity CharlesChandler wrote: Please define what you mean by the word "exists"! Does this "exist"... Again you're changing the topic. What I'm referring to is a material that is non-dispersive yet refractive from radio to optical. Do you have evidence of that? No. Mirages aren't a legitimate example because you have no evidence it extends over such a vast range of frequencies without dispersion. I have said time and time again that lenses demonstrate that in a simple image we don't need to see dispersion but that is not what what I am referring to now. Fine you think mirages are an example of non-dispersion, but there is no evidence that any material could do the same from optical to radio. CharlesChandler wrote: But in the conditions in which inferior mirages form, there is no convection — absolutely none at all. I could refer you to literature on this I would appreciate that.
'14-03-18, 08:33 CharlesChandler	Re: Relativity Sain84 wrote: Fine you think mirages are an example of non-dispersion, but there is no evidence that any material could do the same from optical to radio. You're right that I have failed to produce instrumented evidence that mirages are non-dispersive, and you obviously have no intention of inferring any information whatsoever from the photographs of mirages, except whatever supports your position. For example, in rare cases green flashes have been photographed, which is consistent with refractive dispersion. But if the atmosphere was actually dispersive, and given that there is always a density gradient, dispersion would be typical, not rare. And if I show a photograph that does not show any dispersion, with a greater degree of deflection, you dismiss it as non-instrumented. So you're cherry-picking, and you're citing rare cases to prove a general principle, without explaining why the proof is rare. And you don't see a problem with that. So OK, I'll stop wasting my time trying to convince you of anything there. But there's no getting around the more fundamental issue concerning the lack of rigorous method on the part of GR proponents. Call all of the attention you want to the fact that there is no instrumented evidence of dispersion in mirages — this merely proves my point that GR proponents are not doing their due diligence. Gravitational lensing is one of the cornerstones of GR, and nobody ever did an instrumented study on dispersion in mirages. An an analogy, suppose that one of the cornerstones of GR was that water boils at random temperatures, which in classical mechanics isn't true. I come along and propose that something is getting dissolved in the water that alters the boiling point. You say that I can't cite any instrumented evidence. Therein you win the battle, but you lose the war, because you're saying that their method is scientific while mine is not, and yet they never even bothered to check for contaminants in the water before concluding that the boiling point is random. Likewise, gravitational lensing is one of the cornerstones of GR, but nobody even bothered to measure dispersion in mirages. This is particularly odd in that mirages are extremely common, and therefore would make an extremely easy study. I can only conclude that GR proponents believe whatever they want to believe, and do not do the simplest of sanity checks. And there's just no getting around that. Sain84 wrote: CharlesChandler wrote: But in the conditions in which inferior mirages form, there is no convection — absolutely none at all. I could refer you to literature on this I would appreciate that. I spoke too soon on this — I thought that I remembered seeing instrumented data on the absence of convection in the conditions in which mirages form, but on searching, I couldn't find any instrumented data at all. I guess I was just going on the basis of lore, of which there is plenty, but that doesn't count. I did find one study of the temperature gradient which is curious. Surface convection and the distribution of temperature near a heated surface Last summer we took some temperature measurements under the steady conditions prevailing at the epoch of diurnal maximum temperature above an asphalted road where inferior mirage could be seen on any clear day. The temperature variation with height above a hot surface was shortly afterwards measured also in the laboratory. The lapse-rates were of the order of 20°-30° C. per cm. in the first centimetre, and of the order of 1°-2° C. per cm. at higher levels near a heated surface. The observations showed that there was (1) a 'skin layer' within the first centimetre, and (2) a 'surface layer' extending up to about 20 cm. above the hot surface. The variation of temperature above these layers is practically negligible compared to the much larger variations below. In thermodynamics, there is no model for diffusivity that provides for a "skin layer" or a "surface layer" — the temperature gradient should be smooth, given that the substance being heated is homogenous, which we'd expect air to be. If there was convection, there would be boundary layer vortexes, and these would be hotter than the laminar flow above. But there isn't any instrumented evidence of convection. So this doesn't match theoretical expectations at all. In the absence of instrumented data, the only thing that can be done is to issue predictions, and to collect the field data to test them. So here are my predictions. Temperatures should be similar those obtained in the study cited above, with a hot skin layer 1 cm deep, a warm surface layer 20 cm deep, and ambient temps above that. The humidity should follow the same gradient as the temperature, with high humidity in the skin layer, moderate humidity in the surface layer, and low humidity above that. There shouldn't be any measurable convection (i.e., <0.1 m/s), despite the buoyancy necessary to drive a powerful updraft. There should be an inverted fair weather electric field, with the surface of the asphalt being positively charged, and the skin layer being negatively charged (>10-4 Coulombs per cubic meter). The surface layer should have a slight charge (~10-9 Coulombs per cubic meter), and the air above that should have no detectable charge. There shouldn't be any measurable chromatic dispersion. The last 2 items would take more expensive instrumentation to measure, but the first 3 could be tested quite easily.
'14-03-18, 19:40 Sain84	Re: Relativity CharlesChandler wrote: But if the atmosphere was actually dispersive, and given that there is always a density gradient, dispersion would be typical, not rare. And if I show a photograph that does not show any dispersion, with a greater degree of deflection, you dismiss it as non-instrumented. I don't dismiss it, but I refer you to the same thing I have said everytime about camera lenses. The dispersion is measurable and yet it isn't always obvious in images. Why isn't dispersion always obvious? It doesn't need to be large and nor is it. The setting Sun is a good example because you have such extreme contrast between the brightness of the Sun and the Sky around it not to mention the low angle to the stratified atmosphere, so chromatic effects can be seen just like stars low in the sky. People haven't studied mirages in that regard as far as I'm aware because lab based experiments are prefered, you can control everything and make more subtle measurements. The refractive properties of air have been measured. That's a much better controlled experiment than looking at a mirage. I do not agree with your stance on the importance of mirages for GR. Thank you for the information and discussion but I think we have strayed far too far from discussing relativity and are now and an impasse.
'14-03-18, 19:55 CharlesChandler	Re: Relativity Sain84 wrote: People haven't studied mirages in that regard as far as I'm aware because lab based experiments are prefered, you can control everything and make more subtle measurements. The refractive properties of air have been measured. That's a much better controlled experiment than looking at a mirage. I do not agree with your stance on the importance of mirages for GR. How did they create a density gradient in laboratory air?
'14-03-19, 02:05 Sain84	Re: Relativity CharlesChandler wrote: How did they create a density gradient in laboratory air? You don't have to. For one thing you can make a piece of optics that has a changing refractive index and test theory against that. It's analogous.
'14-03-19, 07:15 CharlesChandler	Re: Relativity Sain84 wrote: CharlesChandler wrote: How did they create a density gradient in laboratory air? You don't have to. For one thing you can make a piece of optics that has a changing refractive index and test theory against that. It's analogous. Oh OK. So is the following an accurate summary of the "logic" by which scientists have concluded that astronomical lensing is not caused by density gradients in atmospheres? Observe that light is deflected by mirages here on Earth. Assume that mirages are refracting light like a prism. Test prisms in the laboratory. Observe that prisms accomplish chromatic dispersion. Observe that astronomical lensing is non-dispersive. Conclude that astronomical lensing is non-prismatic. Conclude that astronomical lensing cannot be attributed to the mirage effect. Conclude that mirages do not need to be studied, because they are irrelevant. Can you spot the logical error in that? Hint: carefully examine #2.