"What then is truth? A mobile army of metaphors, metonyms, and anthropomorphisms"
-Friedrich Nietzsche
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Kelvyquayo wrote:
"What then is truth? A mobile army of metaphors, metonyms, and anthropomorphisms"
-Friedrich Nietzsche
-Friedrich Nietzsche
Truth is something we're still looking for, hence Science.
Nietzsche's quote is little more than an attempt to shock and awe with vocabularly; it hasn't a meaning.
Whatever the wishes of the KKK, black is not the same as invisible. That other dude is right: Black is the absence of coloUr (really the absorption of all visible wavelengths of light), and for an object to be made invisible it would have to be made utterly transparent, not black.
But in this case it seems like the visible wavelengths of light are in fact being reflected from objects, but then somehow being "erased" by the reversal of the light via this "superlens."
The key is that this superlens is a non-natural metamaterial with very unique properties. From what I've gathered, another version of the refractive index (n) is the square of a material's relative permittivity times it's relative permeability. The "relative" part is, I think, relative to the light's velocity. So n shows the extent to which the velocity of light is slowed as it passes through a given material.
Now, certain metameterials are engineered such that both the relative permeability and the relative permittivity are negative. I'm not going to pretend I know exactly what that means or how it's accomplished, but it nevertheless appears to be true and undisputed.
So by taking the negative square root of the product of these two variables, you obtain a negative n for this metamaterial. This means that it has the curious property of creating transparency as far as the given wavelengths of light in question. Weird.
Edited, Thu May 11 22:58:34 2006 by Jawbox
But in this case it seems like the visible wavelengths of light are in fact being reflected from objects, but then somehow being "erased" by the reversal of the light via this "superlens."
The key is that this superlens is a non-natural metamaterial with very unique properties. From what I've gathered, another version of the refractive index (n) is the square of a material's relative permittivity times it's relative permeability. The "relative" part is, I think, relative to the light's velocity. So n shows the extent to which the velocity of light is slowed as it passes through a given material.
Now, certain metameterials are engineered such that both the relative permeability and the relative permittivity are negative. I'm not going to pretend I know exactly what that means or how it's accomplished, but it nevertheless appears to be true and undisputed.
So by taking the negative square root of the product of these two variables, you obtain a negative n for this metamaterial. This means that it has the curious property of creating transparency as far as the given wavelengths of light in question. Weird.
Edited, Thu May 11 22:58:34 2006 by Jawbox
Quote:
Nietzsche's quote is little more than an attempt to shock and awe with vocabularly; it hasn't a meaning.
sci-fi nostalgia aside
What then is truth? A mobile army of metaphors, metonyms, and anthropomorphisms -- in short, a sum of human relations, which have been enhanced, transposed, and embellished poetically and rhetorically, and which after long use seem firm, canonical, and obligatory to a people: truths are illusions about which one has forgotten that is what they are; metaphors which are worn out and without sensuous power; coins which have lost their pictures and now matter only as metal, no longer as coins.
We still do not know where the urge for truth comes from; for as yet we have heard only of the obligation imposed by society that it should exist: to be truthful means using the customary metaphors - in moral terms, the obligation to lie according to fixed convention, to lie herd-like in a style obligatory for all...
I think you are wrong. I think it has a very clear meaning. It means that you don't know sh[Aqua][/Aqua]it and neither do I.
Shall I elaborate?
a sum of human relations, which have been enhanced, transposed, and embellished poetically and rhetorically,
You only know waht you have been sold by those around you.. your family, your friends, media, schooling.. ALL based on someone elses equally skewed interpretation.
and which after long use seem firm, canonical, and obligatory to a people: truths are illusions about which one has forgotten that is what they are; metaphors
This is talking about conditioning, no? Conditioning throughout all of the ages of manking to think in the way that we think today; simply layer upon layer of folly and misperception.
We still do not know where the urge for truth comes from; for as yet we have heard only of the obligation imposed by society that it should exist:
Blinded by social conditioning
to be truthful means using the customary metaphors - in moral terms, the obligation to lie according to fixed convention, to lie herd-like in a style obligatory for all...
Monkey see, monkey do. This mentions "fixed convention". While Nietzsche is most likly speaking from a psychological standpoint, I would go as far to declare that the laws of reality as we know them are more lies based on this conditioned collective viewpoint that is shared by the people on this planet.
Meaningless? Not more meaningless than anything else.
Well, they have that one shirt that consists of a bunch of mini-cameras and screens, so it has the illusion that you can see "through" the person. A material that actually reflects light backwards and somehow cancels it? So...antilight? Sounds odd, but then again, so does antimatter. So meh. Put it on ABC or FOX and I'll give it more credit. =\
On second thought, scratch FOX from that list.
On second thought, scratch FOX from that list.
Jawbox wrote:
Whatever the wishes of the KKK, black is not the same as invisible. That other dude is right: Black is the absence of coloUr (really the absorption of all visible wavelengths of light), and for an object to be made invisible it would have to be made utterly transparent, not black.
But in this case it seems like the visible wavelengths of light are in fact being reflected from objects, but then somehow being "erased" by the reversal of the light via this "superlens."
The key is that this superlens is a non-natural metamaterial with very unique properties. From what I've gathered, another version of the refractive index (n) is the square of a material's relative permittivity times it's relative permeability. The "relative" part is, I think, relative to the light's velocity. So n shows the extent to which the velocity of light is slowed as it passes through a given material.
Now, certain metameterials are engineered such that both the relative permeability and the relative permittivity are negative. I'm not going to pretend I know exactly what that means or how it's accomplished, but it nevertheless appears to be true and undisputed.
So by taking the negative square root of the product of these two variables, you obtain a negative n for this metamaterial. This means that it has the curious property of creating transparency as far as the given wavelengths of light in question. Weird.
But in this case it seems like the visible wavelengths of light are in fact being reflected from objects, but then somehow being "erased" by the reversal of the light via this "superlens."
The key is that this superlens is a non-natural metamaterial with very unique properties. From what I've gathered, another version of the refractive index (n) is the square of a material's relative permittivity times it's relative permeability. The "relative" part is, I think, relative to the light's velocity. So n shows the extent to which the velocity of light is slowed as it passes through a given material.
Now, certain metameterials are engineered such that both the relative permeability and the relative permittivity are negative. I'm not going to pretend I know exactly what that means or how it's accomplished, but it nevertheless appears to be true and undisputed.
So by taking the negative square root of the product of these two variables, you obtain a negative n for this metamaterial. This means that it has the curious property of creating transparency as far as the given wavelengths of light in question. Weird.
Light, when it contacts a particle, is absorbed then remitted. This process slows its progression through a material, varient on the types of particles on it and the density in which those particles are packed. Though it's often overlooked, this also varies with temperature, intensity, and wavelength. Furthermore, this isn't just light, but electromagnetic radition over a varient spectrum.
The index of refraction we've been debating is the rate at which light progresses through a material. As I gave above, (n = c / v), where n is the index, c is the speed of electromagnetic radiation in a vacuum, and v is the speed of the particular representative of electromagnetic radiation in the particular medium. The information you gave above was a good summary of a way of determining it.
As for causing a black color in a material, this is because of destructive interference. Electromagnetic waves can be seen as, well, just that: waves. Waves, when they encounter one another in space, become superimposed. If the waves are equal and opposite with the appropiate phase difference, then their superimposition results a set zero waves, effectively destroying both waves.
One interesting experiment is to take a light source, then a sheet with two thin slits in close proximity (thin being about 1/16 mm, and close being within the same distance). Take a look at the projected light, and you'll notice "bands" of light where parts are brighter, and then dark, and then bright again, and so on. The areas of brighter light are from constructive interference, where the light waves, superimposed, added up to create a greater intensity. The areas of darkness are areas of destructive intereference, where the waves have, in effect, cancelled one another out (the two waves being those from the two slits).
ReofblMobile wrote:
A bunch of Physics stuff
I just did that lab today...you're a stalker, aren't you? o.o
Kelvyquayo wrote:
I think you are wrong. I think it has a very clear meaning. It means that you don't know sh[Aqua][/Aqua]it and neither do I.
Or perhaps there is nothing for anyone to know beyond the words and metaphors and the rest of language that we're taught and that we use every day.
Social Constructivism FTW!
Kelvyquayo wrote:
Quote:
Nietzsche's quote is little more than an attempt to shock and awe with vocabularly; it hasn't a meaning.
sci-fi nostalgia aside
What do you mean?
Kelvyquayo wrote:
I think you are wrong. I think it has a very clear meaning. It means that you don't know sh[Aqua][/Aqua]it and neither do I.
Shall I elaborate?
a sum of human relations, which have been enhanced, transposed, and embellished poetically and rhetorically,
You only know waht you have been sold by those around you.. your family, your friends, media, schooling.. ALL based on someone elses equally skewed interpretation.
and which after long use seem firm, canonical, and obligatory to a people: truths are illusions about which one has forgotten that is what they are; metaphors
This is talking about conditioning, no? Conditioning throughout all of the ages of manking to think in the way that we think today; simply layer upon layer of folly and misperception.
We still do not know where the urge for truth comes from; for as yet we have heard only of the obligation imposed by society that it should exist:
Blinded by social conditioning
to be truthful means using the customary metaphors - in moral terms, the obligation to lie according to fixed convention, to lie herd-like in a style obligatory for all...
Monkey see, monkey do. This mentions "fixed convention". While Nietzsche is most likly speaking from a psychological standpoint, I would go as far to declare that the laws of reality as we know them are more lies based on this conditioned collective viewpoint that is shared by the people on this planet.
Shall I elaborate?
a sum of human relations, which have been enhanced, transposed, and embellished poetically and rhetorically,
You only know waht you have been sold by those around you.. your family, your friends, media, schooling.. ALL based on someone elses equally skewed interpretation.
and which after long use seem firm, canonical, and obligatory to a people: truths are illusions about which one has forgotten that is what they are; metaphors
This is talking about conditioning, no? Conditioning throughout all of the ages of manking to think in the way that we think today; simply layer upon layer of folly and misperception.
We still do not know where the urge for truth comes from; for as yet we have heard only of the obligation imposed by society that it should exist:
Blinded by social conditioning
to be truthful means using the customary metaphors - in moral terms, the obligation to lie according to fixed convention, to lie herd-like in a style obligatory for all...
Monkey see, monkey do. This mentions "fixed convention". While Nietzsche is most likly speaking from a psychological standpoint, I would go as far to declare that the laws of reality as we know them are more lies based on this conditioned collective viewpoint that is shared by the people on this planet.
His quote only has meaning to the fools he was to address.
Edited, Thu May 11 23:17:32 2006 by ReofblMobile
Quote:
(n = c / v)
I fail to see how this can have the same value whether light is traveling though a prism or a vacuum or a curtain.
The formula may still apply, but I can't see how everything would have the same value. Why must the velocity of light be constant?
ReofblMobile, what you haven't really considered or addressed is one of the more important parts -- the metamaterial composing these superlenses. I think that's key to the mathematics if not the actual sciencific practice behind the article.
Quote:
His quote only has meaning to the fools he was to address.
A fool is one who would believe that there is something without meaning.
Jawbox wrote:
ReofblMobile, what you haven't really considered or addressed is one of the more important parts -- the metamaterial composing these superlenses. I think that's key to the mathematics if not the actual sciencific practice behind the article.
Phononic crystals
* When a wave passes through a periodic structure, interference leads to the formation of "band gaps" that prevent waves with certain frequencies travelling through the structure
* Band gaps have been observed for electron waves in semiconductors, electromagnetic waves in photonic crystals and sound waves in phononic crystals
* The periodic variation in the density and/or speed of sound that is needed to make a phononic crystal can be achieved by making "air holes" in an otherwise solid structure
* The phenomenon of "negative refraction" - which can be exploited to make superlenses that can beat the diffraction limit - has been observed with phononic crystals
* Controlling the dispersion relation for phonons both inside and outside the band gap could lead to breakthroughs in both fundamental research and applications
wahtever that means
Kelvyquayo wrote:
Quote:
(n = c / v)
I fail to see how this can have the same value whether light is traveling though a prism or a vacuum or a curtain.
The formula may still apply, but I can't see how everything would have the same value. Why must the velocity of light be constant?
n has varying values for every material. Different material means different index of refraction. The velocity of light isn't a constant between materials, but it is a constant within a single material. Even then, it's only because that's the way it's defined. I can't remember how they 'proved' it or not...2 foot long pixie stick is bad late...twitchy.
Kelvyquayo wrote:
Quote:
(n = c / v)
I fail to see how this can have the same value whether light is traveling though a prism or a vacuum or a curtain.
The formula may still apply, but I can't see how everything would have the same value. Why must the velocity of light be constant?
The idea behind the index of refraction is that it's different for different materials.
Let's do a couple.
c is the speed of light in a vacuum, or about 2.998 * 10^8 m/s. Let's estimate it at 3 * 10^8 for simplicity's sake.
While traveling through space, v, the speed of light, is the same as it is in a vacuum, so v_space = c.
So: n_space = c / v_space = c / c = 1.
The index of refaction for space is 1.
Let's say, for water, light travels only half as fast throguh it, at 1.5 * 10^8 m/s.
So: n_water = c / v_water = c / (c/2) = 2.
The index of refraction for water is 2.
(The water example is hypothetical for numerical simplicity.)
Index of refraction isn't one constant.. it varies from materials, temperatures, wave lengths, etc (as explained in a previous post).
so you're saying that Negative Refraction isn't real?
i drank some NyQuil, I'm kinda slow
i drank some NyQuil, I'm kinda slow
Jawbox wrote:
ReofblMobile, what you haven't really considered or addressed is one of the more important parts -- the metamaterial composing these superlenses. I think that's key to the mathematics if not the actual sciencific practice behind the article.
I've been trying to consider it. It's likely that these "superlenses" have a film properity to them, causing the Newton's rings effect, then reflecting light with a phase difference of 360 degrees as opposed to the typical 180 degree reflection.
The Math I'm using above is more an attempt to explain why what the poster was describing was impossible as opposed to a careful report of what the study really is on. The study's neat, but it's easier to say what it's not than what it is. (Easier to say "that's not good for you to eat" as opposed to "that's not good for you to eat, because it can do blahlblahblah to your blahblahblah because of blahblahblah,".. so on and so forth.) A report on the study's more work and effort than I'm willing to exert on my freetime.
Kelvyquayo wrote:
Quote:
His quote only has meaning to the fools he was to address.
A fool is one who would believe that there is something without meaning.
This is where you make an unfounded statement.
Kelvyquayo wrote:
so you're saying that Negative Refraction isn't real?
Correct.
Negative refraction seems...odd. Hell, even refraction under 1 seems odd. n < 1 would insinuate that a material is speeding light up past the speed of light. I...don't even know how you'd find a negative value out of that...even as you approach an infinite speed, n could only go to 0. I'm too tired and lacking in a degree in math to understand this crap.
so waht's this all about?
http://www.ee.duke.edu/~drsmith/negative_index_about.htm
This is where you make an unfounded statement.
Edited, Thu May 11 23:43:59 2006 by Kelvyquayo
http://www.ee.duke.edu/~drsmith/negative_index_about.htm
Quote:
This is where you make an unfounded statement.
Edited, Thu May 11 23:43:59 2006 by Kelvyquayo
Kelvyquayo wrote:
so waht's this all about?
http://www.ee.duke.edu/~drsmith/negative_index_about.htm
http://www.ee.duke.edu/~drsmith/negative_index_about.htm
The n2=-n1 figure is tripping me out....waves....
my left-brain went on vacation a loong time ago.
Kelvyquayo wrote:
so waht's this all about?
http://www.ee.duke.edu/~drsmith/negative_index_about.htm
http://www.ee.duke.edu/~drsmith/negative_index_about.htm
There's a couple possiblities. Each is long and complicated.
In very, very short:
-360 degree refraction for "black mirror" effect.
-Projected interference
-Research into Quantum Dynamics that the guy who wrote the article took completely the wrong way
Kelvyquayo wrote:
so waht's this all about?
http://www.ee.duke.edu/~drsmith/negative_index_about.htm
http://www.ee.duke.edu/~drsmith/negative_index_about.htm
That's what I was talking about before Kelv. As stated in your article:
Quote:
The sign of the index is usually taken as positive. However, Veselago showed that if a medium has both negative permittivity and negative permeability, this convention must be reversed: we must choose the negative sign of the square root!
Edited, Thu May 11 23:48:48 2006 by Jawbox
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