This is a pretty interesting news tidbit I spotted today. Apparently some researchers have figured out ways to alter the speed of light: A team of researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL) has successfully demonstrated, for the first time, that it is possible to control the speed of light – both slowing it down and speeding it up – in an optical fiber, using off-the-shelf instrumentation in normal environmental conditions. Their results, to be published in the August 22 issue of Applied Physics Letters, could have implications that range from optical computing to the fiber-optic telecommunications industry. Linky Slowing light down is nothing new as it happens when passing through anything more dense than a vacuum, but apparently they've also been able to speed it up beyond the usual 3x108ms-1. There's not much detail given unfortunately but it seems pretty incredible to me that they've managed to speed up the speed of light as this goes totally against Einstein's theoreys of relativity. What do you think?
Hmm. I'll be reading the paper before passing detailed comment methinks! The press release seems to imply that relativity is not broken by the experiment, so I'd guess it's probably some kind of quantum teleportation/faster than light communication thing, similar to stuff you see elsewhere. Sam
Recently scientists are tweaking onto the idea that the speed of light is not as constant as they believed it to be, and that in fact it may have been slowing down as the universe expanded (don't ask me to elaborate on this, just read the New Scientist). This would mean that the theoretical upper limit of light is much more variable than we assumed.
Alright guys, I'm not going to stay for long, but thought I'd chime in. My friend and I have a theory that light can in fact go faster than "the speed of light" without problem. My initial thinking was that light, like all things, is effected by gravity. And as such, it would be effected by black holes as well. At this point you're saying "duh, what's your point?" My point is that, like all things, light must not only bend toward the source of gravitation, but *accelerate* toward it. Furthermore, we have theorized that e=mc^2 is not e=mc^2 but rather m=e^(n-1)/c^n or e=m^(n-1) * c^n depending on the case. Totally whacked-out crazy-hungry-guys-sitting-in-front-of-a-blackboard physics, but we stand by it.
I remember reading about someone that sped the speed of light a few years ago. Though Im sure this process is different.
I have the paper in front of me... not read it yet, but I'll be honest, I doubt it's really as groundbreaking as the title of this topic suggests. If I'd greatly altered c in a new way then I'd have sent my work off to a better journal than APL (don't get me wrong APL's good, but it's a step down from Science/Nature). OT: Your equation isn't correct as it's dimensionally wrong, when you've done a lot of physics the first thing you learn to do with an equation as a first test of 'correctness' is check its dimensions. Put n=1 into your equation, you get E=c, you're writing energy in terms of speed (joules=meters/s) which isn't right! p.s. the paper's abstract: 'We demonstrate a method to achieve an extremely wide and flexible external control of the group velocity of signals as they propagate along an optical fiber. This control is achieved by means of the gain and loss mechanisms of stimulated Brillouin scattering in the fiber itself. Our experiments show that group velocities below 71 000 km/ s on one hand, well exceeding the speed of light in vacuum on the other hand and even negative group velocities can readily be obtained with a simple benchtop experimental setup. We believe that the fact that slow and fast light can be achieved in a standard single-mode fiber, in normal environmental conditions and using off-the-shelf instrumentation, is very promising for a future use in real applications.' p.p.s. ok so the introduction says it all, the first showings of group velocities exceeding vacuum c in this manor are both a few years old: 4L. J. Wang, A. Kuzmich, and A. Dogariu, Nature London 406, 277 2000. 5M. D. Stenner, D. J. Gauthier, and M. A. Neifeld, Nature London 425, 695 2003. ...and published in Nature. Those will be the paper's to read if you want the theory I'd guess
Logic error. Light does not accelerate, its wavelength compresses. This is why black holes can be spotted by the insane ammount of X-rays they emit. Another way of looking at it is if you move towards a source of light at n speed. Does that mean that (relatively speaking) light now hits you at a speed of c+n? Of course not. It just blue-shifts as its wavelenght compresses. Good ol' Doppler. Whacked-out crazy-hungry enough to fail to consider the likelihood of you out-thinking Albert Einstein. I mean, really.
True, if it is a purely Electromagnetical Wave, but light also has a photon character (if I recall my Physic lessons well...) so it's too much simplification to say it only blue-shifts... Say you are discribing a circular orbit around a lightsource. Because your relative distance to the source doesn't change, your relative speed to the source = 0, and there is no dopler effect... But the observed speed of light is different (2 vectors perpendicular to eachother = Pythagoras) If you read a couple of your posts across this forum you could say you find it unlikely for anyone to have good ideas... But that put aside, Einstein also stated that he had his doubts about the absolute correctness of his theory... You are acting like the way they did way back, when some intelligent person stated that the earth revolved around the sun... [sarcasm]I mean really, how can that be?[/sarcasm]
i dont know much about this subject but i have to agree with glider on this fact, when the first motor cars were built they thought if you went faster than 30MPH you'd melt and die and this have been proven wrong (except for the old people on the way to work who insist on driving at 30 in a 60). when Einstein came up with the theory of relativity the people around him must of thought he was mad and talking out of his backside but he has been proven to be a genious, but what is stoping the the "genuses" of today with far more sophisticated equipment etc proving that his equation is wrong? or need a slight ammendment? Could light be like sound? ie the distance and speed at which it travels at are affected by the air it moves through, so why cant light behave like this? you can faster than the speed of sound, (mach 1) and even faster so why not with light but what does finding out the speed of light prove? is the speed of light the fastset we can travel? or will we be able to travel faster? just a thought
mmm agreeing with someone and backing it up with zero scientific fact is not a good way of showing your point
I don't need a scientiffic proven fact to back up someone's opionion... They are, but on the other side they aren't... They are both waves... One is a pressurewave, other is an Electromagnetical... But Light doesn't strictly follow all the rules about Electromagnetical Waves... Light just has such a complex behavour
Never said it only does that. But we're trying to keep it relatively straightforward here. Again, logic error. Say you are running in circles around a tennis ball launcher that launches balls in a straight line away from it, in all directions simultaneously. If I throws them out fast enough it is bound to hit you some of the time. This does not mean however that the ball had to travel a combination of two vectors to get to you. It went along a single vector, and then your movement happened to intercept it. Again, not at all what I am saying. However I am sometimes amazed at how people can think that an afternoon of off-the-wall musing is enough to come up with an idea and assume that experts in the field have never even considered it, or that it is enough to topple a repeatedly proven and established principle discovered by one of the greatest minds in theoretical physics. I mean, if it was that easy the scientific world should be ablaze with new insights and inventions all the time. A lot of good science starts with "What if?" off-the-wall, out-of-the-box musings and new, unconventional ways of looking at things, but then you have to follow through the scientific process, of testing it, proving it, modifying and refining it until you have a real working prinicple. Off-the-wall ideas are just that: ideas. Good ideas, perhaps. Clever ideas, certainly. But that does not make them the right idea: a working priniciple, or establised fact. And you are up against some good competition: Einstein, Feinman, Hawkins, the finest engineers at NASA, MIT... the list goes on. You think they never had an original idea in their life? But that was not enough. They had to put their science where their idea was. And sometimes, that took years. I came up with a new cognitive model for Autism some time ago. It's pretty sound (I think), in that it builds on established principles. I may even be right. But I also know that at this stage, it is just an idea, not fact. A good idea, but not necessaily the right idea. I also know there are a lot of other bright psychologists out there who may have had the same idea. They may even know for a fact that this idea wrong. So all I can do is say: "Hey guys, what if?..." and see what others think. And if others come up with some prety good reasons why I'm likely to be wrong, I cannot be upset about it. A colleague and I also just submitted an article on psychosis and hearing voices in deaf people. Interesting: we both had the same idea at the same time. We think our proposed theory/model is right. But another colleague (deaf, incidentally) is actually doing research on this, and she may very well shoot our idea down in flames. Soon, she may know why our model is wrong. Such is science. If he has no data to back it up, it's just an idea. A good idea perhaps, and a clever one, and one that might work, but he'd have to show the astronomical observations to support it. Else it is just an idea. No more, no less. And he wouldn't be able to say that he is right and the others are wrong. And Galileo Galilei, if you care to remember, gathered lots of data to support his claim.
You do if you want to back it up as scientifically correct. Pressure waves depend on a medium. Light does not. Light does slow down in a medium, but in the relative vacuum of space, as far as all data tell us, it has a top speed. Light is odd. Its... quantum. In other words, we don't know a lot about it. However we've been observing it for a while now, and generally have a good grasp on how it behaves, even though we don't always know why. Now if you can get proof to the contrary of these observations, than you can say established models are wrong.
Monkey only agreed with the fact that often new idea's are stamped as WRONG, and are proven later along the road... That is nothing scientiffic... Now read that again, how can light waves be independent of the medium, but do slow down in a medium? Guess they depend on the medium then. But I can follow you that the speed is allmost constant in Vacuum (that is what you meanth I hope) altough I have my toughts about that... In this case it does matter that it doesn't have a strict EM-wave behavour... Yes, I remember that Gallileo gatherd a lot of data... But you are once again missing the point But a bit more on topic... Now, then explain to me why during a solar eclipse, stars that are behind the sun are visible... I allways tought that to change a direction of an object, you need an acceleration... and this brings us back to the fact that light isn't a pure EM wave, but also has a photon-proprerty... So (follow the way I build this up, without scientiffic proof) If light traves straight through space (~vacuum) directly towards something wich has a huge gravitational field, why wouldn't it accelerate, like everything else. The previous paragraph shows us that light is subject to gravitation... [Edit: removed some typo's ]
Well, scientific as in proven or borne out by experience, really. Thing is, a lot of new ideas stamped as wrong are later also proven to be... wrong. The trick is to know which is which. Pressure waves need a medium to travel though. Without a medium they don't exist. They're just movement, really. Light (as you have pointed out) is both a wave and a particle. It is its own medium, so to speak. That doesn't mean it cannot be affected by other mediums. Back to good ol' Einstein. He argued that gravity curves space-time. So it is not light that is bent (or accelerated, or affected in any way), but the space-time it travels through. From light's point of view, nothing has changed. It is still travelling in a straight line as always. But it is the space-time it travels through that has curved. BTW, this theory of the curvature of space-time has also been proven. So that's why you don't.
I allways learnd that it is the lightwave that bends... Like when the sun goes down the horizon, but it still is light... Your explanation reminds me of "Back to the Future". The thing Einstein said about space-time is time dillution, that you age less when you travel at the speed of light... I follow your way of thinking untill the /// but after that it's blabber... Light is it's own medium (even so to speak)... I allways tought medium is the thing it travels trough... Travel trough yourself? And if that was possible, how can it thus be in 2 mediums at the same time?
That is athmospheric scatter and reflection. It also refracts like a lens. The wave is the pattern, or information if you will, the photon the medium which carries it (like with sound: the pressure wave is the information, the air the medium that carries it). Take a letter. Is it information, a medium, or both? Take a letter that is being carried by a postman. What is the medium of the information it contains? The paper it is written on, the postman which carries it, or both? It all depends on your point of view, I guess.
No, The wave is the EM component, the Photon the particle component... The medium is where they go through... It's an other definition of medium we're using. You are talking about a carrier medium (like a HD) I'm talking about a medium to travel trough... entirely different... But like many theads, we're far off the origional topic... so... I think, and Mr Nexxo it is my tought, so just an idea, no proven fact, that if there are certain conditions that make light go faster than the constant c. And I think, once again the same condition, that gravity might be a factor in this (Black holes "suck" up the light due to gravity). This gravity that can bend the light (thus accelerate) must be able to speed up the lightbeam too. What those conditions are, I don't know... Nor do I bother actually... That's my view on it, so my .02€, not scientiffic proof [EDIT] So, like allready was stated by Ubermich, don't believe in the pretty formula's, but I back the tought-process
Erm, no. The speed of light in a vaccuum is a constant. Umpteen gazillion experiments have been done that confirm the fact. Minds far more intelligent than you or I have done enough work on both special and general relativity without any hitches. You can have an "acceleration" of light due to gravity but that only changes the direction, not the speed. Changing the direction or velocity of something does not necessarilyimply changing the speed! Well, speaking as someone with a Masters in physics (that sentence makes me sound like a ponce but it was strangely enjoyable) my opinion is that your opinion is 100% wrong San
