Mosheh Thezion, What's the science behind this? Kmguru, And this? Chagur, I was under the impression that the general consensus among active researchers is that gravity waves propagate at the speed of light. (As reported in New Scientist.) I am also under the impression that instantaneous communication will violate relativity. There are two things that I know of which act across space instantaneously: probability wave collapse and the effects of entanglement. One may not exist as a real phenomenon (rather than as a human aid to calculation); the other cannot transmit information. Seems to leave the prospects for interstellar communication limited to purely subluminal velocities.
Say, for instance, that two entangled photons are produced in a subatomic event. They speed off in opposite directions until many light-years separate them. Then imagine that you come along and attempt to measure the spin of one of them. Because of quantum uncertainty (which I am gradually and reluctantly coming to accept is a genuine limit to knowledge) the photon did not possess a definite spin value until you interacted with it. However, now that you have 'forced' it to assume one particular value, should its distant partner also be measured it will possess the exact same value (or the exact opposite - I'm not sure). "Spooky action at a distance" has been demonstrated, though no information has been communicated. Einstein and some others apparently tried to argue that all this showed was that the photons both share the same value for spin from the moment they are created. However, (fairly) recent experimentation has shown that this is not the case, and that both photons do genuinely assume a common value only when they are forced to interact with the environment (observer). I think that it was a statistical argument which has convinced physicists of this.
Zephyr: The quantum phenomena involved are controlled by probability. You cannot decide in advance what state will be measured. You merely know what result will occur at a distance site after you have made a local measurment. Imagine that two pairs of dice could be entangled. I throw one pair here on Earth and you throw the other pair on a planet in the Alpha Centauri system. When I see my result, I know yours and vice versa. It seems hard to believe that such a phenomena could occur, but that is what the quantum theory boys say is so. BTW: I suspect that this thread belongs in the SciFi Forum, although is is probably not as far out as some others accepted here as science.
Here is something I found very interesting from a few years ago. When it comes to interstellar communication, everyone automatically starts thinking about EM radiation. Here’s something to think about……! (I have posted only the abstract of the paper) <blockquote>Inscribed matter as an energy-efficient means of communication with an extraterrestrial civilization Christopher Rose and Gregory Wright <I><B>Nature</B></I> 431, 47-49 (2 September 2004) It is well known that electromagnetic radiation—radio waves—can in principle be used to communicate over interstellar distances. By contrast, sending physical artefacts has seemed extravagantly wasteful of energy, and imagining human travel between the stars even more so. The key consideration in earlier work, however, was the perceived need for haste. If extraterrestrial civilizations existed within a few tens of light years, radio could be used for two-way communication on timescales comparable to human lifetimes (or at least the longevities of human institutions). Here we show that if haste is unimportant, sending messages inscribed on some material can be strikingly more energy efficient than communicating by electromagnetic waves. Because messages require protection from cosmic radiation and small messages could be difficult to find among the material clutter near a recipient, 'inscribed matter' is most effective for long archival messages (as opposed to potentially short "we exist" announcements). The results suggest that our initial contact with extraterrestrial civilizations may be more likely to occur through physical artefacts—essentially messages in a bottle—than via electromagnetic communication.</blockquote><P>
Only a bit of food for thought. I am well aware that supporters of relativity reject particle entanglement violates relativity by the assertion that information has not be transmitted. That frankly is a bit "post ad hoc CYA" as far as I am concerned. It would appear that regardless of our current or even ever future inabiity to transmit information that we can use by particle entanglement, the fact that information is being sent seems most obvious. If these particles are not communicating as to their status and changes then the particle entanglement phenomena is "Spooky" indeed. Please Register or Log in to view the hidden image! It would seem without arguement that such particles are infact communicating by some instantaneous means. Their respective quantum condition and changes "IS Information" regardless of how others would like to argue to the contrary. It is important to note that no temporal conflict occurs when nature communicates FTL.
MacM, I suppose that you could claim that information has been passed between the two entangled particles. But the 'knowledge' of this information is strictly restricted to the particles themselves. Imagine that you and I, separated by light-years, each possess a mutually entangled photon. By measuring the spin of yours you cannot ascertain that I have or have not done the same. The most you can deduct is that if I did measure it I would obtain the same (or opposite?) value. To you (and to me) the result of measurement will still suggest that the photon has only 'opted' for one value or another at the moment of interaction. After this interaction has occurred the entanglement is lost.
Hercules Rockefeller, That's an interesting idea - it's got old-school appeal. While still ignorant of the figures I think only the most parsimonious of civilisations would begrudge the extra energy required for a narrow beam EM transmission. But then who's to say just how miserly ET is with its energy?
Oh, I agree nature has one up on us in this regard but I do object to those that claim information has not been transmitted FTL. I think the particles would disagree (as should any reasonable thinking individual not married to the prohibition of FTL by relativity).
Hercules Rockefeller: You have an interesting name implying incredible strength combined with incredible wealth. If such is the case, I congratulate you: Unlike some who make disparaging remarks due to jealousy. Tight beam radiation & the sending of physical artifacts do not seem worthwhile due to the low probability of either method ever reaching an intelligent civilization. A bottle with a note tossed into the Pacific Ocean is many orders of magnitude more likely to be found than a tight beam message or a physical artifact sent out into the universe. At the risk of starting a flurry of posts claiming otherwise, I would like to point out that there is little reason to expect more than one intelligent civilization per galaxy at any given point in time. It is quite possible than some (perhaps most) galaxies contain no intelligent civilizations. While there is good reason to expect life to exist whenever the conditions are suitable, intelligent life is a very low probability occurrence. MacM: If you accept the analogy of entangled dice, can you describe a mechanism whereby you could transmit useful information using such dice? If you do not accept the dice analogy, might you describe how you would transmit useful information via entangled quantum entities? Since the Quantum Theory experts admit to not knowing how to do it, I do not expect you to have a useful method. Others: John Gribbin (See Schrodinger’s Kittens & the Search for Reality) claims that the Von Neumann hidden variable proof is invalid (Id est: Hidden variables are possible contrary to Von Neumann). Gribbin claims that this was asserted by Grete Hermann in 1935, but ignored. Gribbin states that Bell refuted the proof in about 1966, later claiming that it was not only invalid, but silly. If the Von Neumann proof is invalid (this is likely due to the work of Bell & Aspect), then entangled particles need not rely on lack of local causality. They could be an indication that objective reality is sometimes a valid concept. The quantum world is really weird. Some experiments involving entangled particles seem explainable assuming objective reality, thus retaining local causality as valid. Other experiments involving entangled particles (EG: Polarization phenomena) refute objective reality. The two slit experiments indicate that certain quantum particles (including atoms) sometimes act like waves and sometimes act like particles. Entangled particles experiments (perhaps only thought experiments) indicate that sometimes objective reality is valid and sometimes it is not. Perhaps, the best interpretation of quantum phenomena requires admitting that some of our intuitive concepts are not applicable to the world of quantum phenomena. Id est: Perhaps we should give up the quest for an understandable model and be content with the predictive value of the equations. The above view seems no worse that accepting the mathematics of 4D & higher spaces without being able to visualize the geometric objects described by the mathematics. For example consider the following. A 4D hyper-cube has vertices at which 4 lines are mutually perpendicular. Worse yet: In general, an nD hyper-cube has vertices at which n lines are mutually perpendicular. The diagonal of a unit nD hyper-cube is SquareRoot(n). This implies that a 441D unit hype-cube has a one unit side & a 21 unit diagonal. Consider a unit 16D hyper-cube with an inscribed 16D hyper-sphere. You can fit 256 hyper-spheres in the corners, tangent to the faces and to the inscribed sphere. Each of those 256 hyper-spheres are significantly larger than the central inscribed hyper-sphere. The above and various other claims relating to nD geometry can be proven mathematically, but are impossible to visualize or model in our minds. Is it a crime to give up on being able to visualize some Quantum World concepts which are provably valid?
If I could I can assure you I woudn't be writting my views on this forum. Please Register or Log in to view the hidden image! Show where I claimed I could. Then tell us if you subscribe to the arguement that the particles are NOT commmunicating any information when they are changing state. I see no conflict in that in that matter is nothing but compacted energy. Energy seems to be in the form of waves. Consideration of anything greater than 3D is a waste of time. Pun intended. Yep.
MacM: You asked the following. Yes I do subscribe to that argument. Suppose I send a simple question to an astronaut who is a few light hours distant. He need only answer yes or no, requiring the transmission of a single bit of meaningful information (Id est: One for yes & zero for no). To the best of my knowledge, there is no way for him to transmit that single bit of information using particle entanglement, even if we are allowed to set up the entangled particles in advance of transmitting the question. Until somebody describes a mechanism for transmitting a single bit of information, I will continue to subscribe to the argument. BTW: I assume that you are aware that quantum particles obey probabilistic laws, not controllable deterministic laws.
Then you are applying an incorrect standard to the terms: WEBSTER: Communication - (1) the act of transmitting. (2a) - a giving or exchanging information,.... "Or" is an important two letter word here. Communication need not be a system of back and forth replies. It can be and in the case of particle entanglment IS one way communication and is "giving" information, not exchanging information. Certainly. But that doesn't change the fact that the particle being measured communicates, "gives" information, to the other particle.
MacM: You are either nit picking or ignorant of what the Quantum Theory boys mean when they say that no informnation can be transmited via the use of entangled particles. In case you are ignorant of their claim, I will state my understanding of it. The Quantum theory boys state that I cannot use any entangled particle phenomena to send a message FTL to a distant observer. For example, I cannot inform the distant observer of the current temperature in my apartment using entangled particle activities. I think that they do acknowledge FTL action (Id est: Spooky action at a distance), but they deny that any useful informtion is transmitted FTL or otherwise via entangled particle phenomena. I concur with the latter claim, but am not sure about the former. I am not sure exactly what the Quantum Theory boys are claiming with respect to entangled particles. They obviously claim that a local measurement provides a knowledge of the result of a distant measurement. I do not know if they are claiming a cause effect relationship acting FTL. I have no idea of what they claim if no measurement is ever made at the distant location. As indicated by a previous post, I am not quite willing to acknowledge FTL interaction between entangled particles. Einstein favored a hidden variable explanation for the spooky action at a distance. Due to Von Neumann (and perhaps others), hidden variables were considered to be impossible until Bell and Aspect showed that the Von Neumann proof was flawed. When the Von Neumann proof was refuted, FTL activity need not be used as an explanation for entangled particle weirdities. At least that is my interpretation of the implications of rejecting the Von Neumann proof. Frankly, I do much confidence in my opinions on this or any other Quantum phenomena. I have even less confidence in your opinions on this or any subject involving SR, GR, or QT. I think we have an argument between sombody with poor eyesight and another who is almost blind. BTW: It is naive to use a dictionary definition in the discussion of a complex subject.
I see. I thought that you could change the spin of one of the particles and the other would change to reflect that, like forcing one of the entangled dice, but since you can't ... that doesn't really help. Taking the hidden variable explanation, you can do the same without entanglement - if a planet flashes either a red or blue light in all directions, then two people an equal but opposite displacement away will see the light and deduce that the other person is seeing the same colour. The only difference engtanglement makes is that there's no 'middle man' choosing the colour.
T=CR... TIME equals capacity times resistance... and if the resistance is low.... as in zero..... then... instantanious communication across what can be called subspace can occur... in the electrostatic realm..... dont ANY of you study electronics??? -MT
If you understood english you would know I have not commentedon what the QM boys have said. Nor have I claimed we can communicate using particle entanglement. I have said and repeat that the claim no information has been sent FTL is outrageously false. The mere quantum status of a particle is information and the change of state is information. The arguement put forth is BS and only used as a eans of ignoring the failure of SR. Only with respect to very specific technical or scientific terms. It is even more naive to be unable to converse in absence of some supporting relavistic formula and suggests the person is ignorant of basic physics.
