What is Digg?Sponsored by Best Buy
Best Buy finds gold in Iowa. view!
youtube.com - Best Buy employee, Danielle Kelly, sings her way into holiday campaign.
116 Comments
- DDRSkata, on 10/12/2007, -0/+56Wow, and if kids running into glass doors wasn't a problem already...
- ophello, on 10/12/2007, -5/+31No, the glass would still refract/bend light, causing a distortion to appear. It would not be invisible.
- brodskie, on 10/12/2007, -1/+26Light's speed really does slow down in materials. This is not a far fetched theory, it can be proven if you know some electromagnetic properties of the material. The statement that everyone is familiar with is really "The speed of light in a vacuum is constant"
- bryant, on 10/12/2007, -2/+25In other news a surge in videos submitted to AFV has been reported...
- ozroy, on 10/12/2007, -0/+14Except you wouldn't be able to see the refraction unless you can compare it to a non-refracted image. So if you use the glass as you would usually use glass (ie a window in a wall) you will not see any refraction, and it would appear invisible.
It's exactly like looking into a lake, you can't see the refraction the water causes until the put the end of a stick in the water. - ophello, on 10/12/2007, -5/+19Light does not slow down in a substrate. That is a false way of explaining refraction.
Light is absorbed and re-emmited repeatedly bewteen atoms, causing the overall appearence of light "slowing down", but it does not actually move slower. - merreborn, on 10/12/2007, -2/+14You want pictures of a substance that's totally transparent?
Wait, was that sarcasm? - stable, on 10/12/2007, -0/+11This kind of glass has exactly the same refraction index as the air around you, so having a ball of this glass in front of you would be the same as having a ball of air. In other words, you wouldn't be able to see the glass because it wouldn't refract and inherently wouldn't reflect.
The reason glass, water, and other transparent materials reflect light is because they have a greater refraction index than the air around them. Want a way of telling whether reflection is being caused by refraction? Use a vertical polarized filter (like polarized sunglasses) and look at horizontal surfaces at an angle of 45 degrees. If the reflexes on them darken or disappear it's because they are a result of refraction.
Of course this also prevents this kind of glass from being used in lenses. - ThirdPrize, on 10/12/2007, -1/+12No, but there is a Windows connection.
- radu79, on 10/12/2007, -1/+12No, it wouldn't become invisible because the light has a different speed in the glass. So you'd be able to notice it's there, because some objects will apear to be distored if you put that glass in front of them (partially covering them, that is).
Plus, what happens when the viewer is not perpendicularly looking at an object? - Lingur, on 10/12/2007, -0/+11Wait, you killed him?
- culbeda, on 10/12/2007, -0/+11Ha ha ha... I had a 8-10 year old kid slam into one of my glass doors at full speed during a big party. Even loosened the trim that holds it in place. (This was just before he broke my toilet, broke a statue (that I hated anyway), threw a Frisbee indiscriminately at my party guests, tried to write on my kitchen counter with a felt marker and decided to play UNDER my gas grill while I was using it.
We called him "The Tornado".
I don't miss him. - gotamd, on 10/12/2007, -0/+10It's too bad this article has no real content. That sounds kind of interesting, though I've very skeptical of being able to produce a material that lets 100% of the energy in light pass through. Air doesn't even do that...
- merreborn, on 10/12/2007, -1/+11http://en.wikipedia.org/wiki/Speed_of_light#Light-slowing_experiments
Rainbows and prisms wouldn't work if light traveled at the same speed through all mediums. - ophello, on 10/12/2007, -4/+13I wasn't responding to your comment/joke. I was responding to the article comment at the top of the page:
"If 100% of the light passes thru, then wouldn't that render the glass invisible? hmm...."
I have a sense of humor, thanks. - brodskie, on 10/12/2007, -1/+9why not? superconductors allow all electricity through.
- Phil246, on 10/12/2007, -0/+8you missed the joke ;)
He was having a go at the surge of non-tech related stories appearing on digg, His post was sarcastic - hseldon, on 10/12/2007, -0/+8I'll believe it when I see it...oh...when I don't see it. Never mind.
- Oniony, on 10/12/2007, -1/+8The emperor's new windows.
- mrpackrat42, on 10/12/2007, -1/+8The article is a little misleading. Negative index of refraction doesn't have much to do with reflectivity. It means that light passing through the material is bent in the opposite direction than happens in normal materials. There's a much better explanation here:
http://www.eetimes.com/story/OEG20020827S0019 - mikaelc, on 10/12/2007, -0/+7To WaterDragon:
Science is not necessarily about answering questions about what observed phenomena *are* (that is a question of ontology, which belongs to metaphysics).
Science tries to establish theories and *predict* the behaviour of phenomena.
WRT to light, science has been extremely successful and light is one of the best described and understod concept in physics. Think of the prediction of light bending (from general relativity) or the constructions of lasers (described by Quantum Mechanics theory). - majorbabu, on 10/12/2007, -4/+11i've attached a picture of this new glass to my comment.
here it is: - mrASSMAN, on 10/12/2007, -1/+7***** people, it's not for "new windows" it's for: "improvements in low-loss fiber optic communications, the development of telescopes and cameras well-suited for dark subjects, and the emergence of optical equipment we have never seen before."
- thecolor11, on 10/12/2007, -1/+7http://www.google.com/search?q=left+handed+materials
- HyperX, on 10/12/2007, -1/+7Finaly an intelligent statement light is absorbed differently by differnt molecules and this is what makes light seem coloured so for it to be seethrough it must retransmit all the light that hits it
- whybird, on 10/12/2007, -0/+5WAKE UP! http://digg.com/technology/Transparent_Aluminum
- connerfitz, on 10/12/2007, -1/+5It's quite interesting really, Sir Prof John Pendry brought the idea back to life recently (was first envisioned by a Russian guy in the 60s), he had the idea that if this material existed then light could be focused down past the optical limit of the wavelength. Some guys at UCLA confirmed this with a nano lense.
Interestingly also the light is left handed, when tradtionally if you shined light on a shaped piece of glass it bends into the normal, for these materials it bends away from the surface normal. - jrbrewin, on 10/12/2007, -0/+4read the article, second paragraph.
"The prism structure has a negative refractive index, which makes it truly transparent to light, allowing it to pass freely through with no reflection."
http://en.wikipedia.org/wiki/Refractive_index - lendrick, on 10/12/2007, -1/+5Nothing said it wouldn't *absorb* any of the energy. A dull, black surface might reflect very little light, but it would absorb a lot.
- webXL, on 10/12/2007, -5/+9yawn... Boring!
Wake me up when Transparent Aluminum is invented. - Settra, on 10/12/2007, -3/+7Negative
- emiles, on 10/12/2007, -0/+4Read the article linked by mrpackrat above. A negative index of a refraction is more or less a nickname for a material that obeys kind of a backwards Snell's law and has some other weird properties. It's not meant to imply that the light is moving backwards or anything.
Also, (though this has been pointed out to death here on digg) those experiments where light "goes faster than lightspeed" are experiments where the *phase velocity* of single fourier modes of the light exceeds c, but the group velocity of the wave packet of the light does not, and cannot, exceed lightspeed. - cocoamix, on 10/12/2007, -0/+3In case anyone ever wondered what the writing along the bottom is in all those electron micrographs:
Riken is the scope manufacturer.
SEI stands for Secondary Electron Image (the most common kind of SEM picture, as opposed to Backscattered Electron Images and Characteristic X-Rays.
5kV is the accelerating voltage of the cathode at the bottom of the scope used to "pull" the electrons down towards the sample. Sort of analogous to "brightness" in a light microscope.
950 is the magnification
10 microns is the size of the scale bar
WD 14mm is the working distance, which is the distance between the lens condenser and the top of the sample. The larger the WD, the greater the depth of field.
Yes, it is what I do for a living. - tamoneya, on 10/12/2007, -2/+5how do you get a negative index of refraction.. Doesnt really make sense.
- inboxnews, on 10/12/2007, -1/+4Pretty cool:
"In the future, this type of metamaterial prism could lead to improvements in low-loss fiber optic communications, the development of telescopes and cameras well-suited for dark subjects, and the emergence of optical equipment we have never seen before." - EruLabs, on 10/12/2007, -0/+3The idea of a photon passing a metal gate smaller than the freq. of the photon, and reporting a refletion rate of >1, meaning the photo is accelerated is amazing. think of optical computers that are instant in everyway, faster than the human mind to the point where loading is completly forgottan forever.
Jee people, considering IBM, INTEL, and AMD, you know the new "intel optic inside" or some lameness will be like 1000$, what do you think the cost of your PORCH WINDOW WOULD BE, YOU DUMB REDNECKS.
i cant wait for the superconductors, and you know someones gonna do it someday. - spirko, on 10/12/2007, -0/+3For those who would like to see the original research and have access, the reference is Phys. Rev. B 73 (2006) 125423. http://link.aps.org/abstract/PRB/v73/e125423 is the URL.
- Otto, on 10/12/2007, -0/+3It's incredible how people will comment on stuff that they clearly don't know ***** about.
A material's refractive index has to do with a material's permittivity and permeability. Both of these can be either positive or negative. If they are both positive, then the material is transparent. If either is negative, then the material is opaque. However, in nature, no such material has both of them as negative.
This "Russian guy in the 60's" that people are posting about: His name was Victor Veselago. He proved that a theoretical material which had both of these values negative would be transparent to light. That's really all he did in that case, but such materials proved to have intersting properties. Mainly, they have a would have a negative refractive index.
What does a negative refractive index mean? Well, mainly, when a beam of light enters a denser material, it is deflected towards the normal. This is called Snell's law. Think of a beam of light going from air into glass. Snell's law says that the refractive index of the "from" material (air) times the sin of the entering angle = the refractive index of the material being entered (glass) times the sin of the angle it's moving in the glass. Now, if the glass has a negative refractive index, then the light will actually be going in the opposite direction. North becomes South, that sort of thing. It's like the normal line (the line perpendicular to the glass surface at the point where the beam of light enters) is suddenly a mirror. The light completely bounces off normal and goes the other way.
Other weird ***** happens too. Doppler shift is reversed. Cerenkov radiation goes backwards (making that spooky glow tend toward red instead of blue?).
Anyway, they made a "superlens" sometime last year at Berkeley, but they didn't use a material with a negative refractive index. Such a material would actually be layers of different materials at microscopic sizes. This is called a "metamaterial", and the combination of the two materials sandwiched would give it the negative refractive index effect.
Looking at the picture in the article, it looks like a textbook example of Pendry's perfect lens, with the C-shape and all. The wires are ferroelectric, the ring around each one acts as an inductor, the open ring acts as a capacitor, making it form an LC circuit. When light (which is an electromagnetic field) goes through the ring, it induces a current and generates a field perpendicular to the magnetic field of the light. There is a magnetic resonance so the permeability is negative, and thus the index is negative too. The material as a whole has a negative refractive index because of the properties of the materials used and their specific arrangement.
But the text of the article is crap. Light doesn't pass through it with no refraction. It passes through it with a negative refraction, which is entirely different. - spirko, on 10/12/2007, -0/+2Yeah, the misinterpretation here is pretty harsh. They mention negative index of refraction once, but that's not what they're doing.
The diagrams in the original article at http://link.aps.org/abstract/PRB/v73/e125423 indicate that the transparency is only at a certain angle. The research is built on the phenomenon that causes Brewster's Angle http://en.wikipedia.org/wiki/Brewsters_angle . "In conclusion, we have investigated a phenomenon whereby the Brewster effect can be produced for both p- and s-polarized light simultaneously." - ophello, on 10/12/2007, -0/+2@radu79
"...it sure seems to me, based on grade school math, that light slows down in non-vacuums."
False.
For all practical purposes, we can calculate that the speed of light is "slowing down" because it is mathematically conveinient to calculate like this. However, this sorely misrepresents the properties of light traveling through a substrate.
Light does NOT put on the breaks when entering a substrate: it is absorbed and emitted between atoms, and upon being absorbed, the photon technically doesn't even exist. Since it is not re-emitted immediatelly after being absorbed into an atom, and after a few billion of these repititions, it takes longer to exit the other side, which to a humble observer, seems like the light slowed down. Nowhere in the process does light actually travel slower. It goes full speed between the atoms, and doesn't exist in the absorbtion/emission period.
The speed of light is a constant. No exceptions. - ophello, on 10/12/2007, -0/+2Letting 100% of light through is not some violation of law or phyiscal code, just as there is no law that says you cannot achieve 100% efficiency in an internal combustion engine. While the latter is not comparable to light passing through glass, you see my point.
When dealing with light, it shouldn't make you skeptical to see that a glass surface lets all light pass through through a chemical or electrical means.
Superconductivity is a property that allows zero resistance in an electric current. Is this so hard to believe? - fitchmicah, on 10/12/2007, -0/+2This story drastically misinterprets what is going on. The index of refraction says nothing about what wavelengths of light are absorbed and pass through the material. It just means that the light refracts at a reversed angle to the normal compared with how it would bounce in a material with a positive IOR!
http://physicsweb.org/articles/world/16/5/3/1/pwpia1%5F05%2D03 - dwoloz, on 10/12/2007, -2/+4I build car computer systems and touchscreens are usually the input method of choice but their glass interface layer creates a lot of glare and reduces brightness significantly (making sunlight viewability impossible). Equipping a touchscreen with some of this glass would have amazing implications
- MacGeekGuy, on 10/12/2007, -0/+2Thanks! That's great info... I appreciate your sharing it.
- Kazanoe, on 10/12/2007, -1/+3If you think the kids will be a problem, think about what would happen if airports or high-rises ever installed them...
a good portion of the birds would go extinct! - fletchowns, on 10/12/2007, -0/+2Very carefully. And be sure not to set it down.
- CaptainMal, on 10/12/2007, -1/+3yeah you guys are arguing semantics now really. The explanations were good. leave it at that.
- deepsub, on 10/12/2007, -2/+4@ophello:
"Light does not slow down in a substrate. That is a false way of explaining refraction."
Well, since the formula for index of refraction is n=c/v, where n==index, c==speed of light, and v==speed of light in a material, it sure seems to me, based on grade school math, that light slows down in non-vacuums. - sbostedor, on 10/12/2007, -3/+5I hear the simultanious thud of bird beeks in our future
- JackCroww, on 10/12/2007, -2/+4@Waterdragon
Just because you don't understand the science, doesn't mean it is invalid. It just means you don't understand the science. I'll leave it to you to figure what this says about your intelligence. -
Show 51 - 100 of 116 discussions
© Digg Inc. 2009
— Content created and posted by Digg users is