- #1
Reshma
- 749
- 6
Can someone explain me the ether drag hypothesis?
Fairfield said:While you are on the topic of a controversial ether I think I should mention that in 1920 A. Einstein accepted the idea that there is an ether. Please check the following link for more on this.
````
http://www.tu-harburg.de/rzt/rzt/it/Ether.html
selfAdjoint said:Oh lord, not that old canard again!
Short answer: what Einstein meant, as is clear from the whole quote, is that his curved, active spacetime in general relativity had taken the place of the old ether as a "something" extended through space (it WAS space!) that supported physics. He did not accept any form of the luminiferous ether that was thought up in the nineteenth century.
yogi said:As for whether a classical ether exists in the sense of a medium for light propagation, it is still unresolved. Space as a capacity per unit length and an inductance per unit length and those two factors determine the velocity of em waves just as they do in a transmission line. You wouldn't argue that the inducance and capacitance of a transmission line do not determine is impedance or its propagation properties - so why would it make sense to ignor these same factors when dealing with space.
Neither MMx nor any of the other over and back experiments proved anything about the one way velocity of light, ergo they do not disprove the existence of a medium. The invariance of the round trip velocity of light is not inconsistent with an ether because time dilation provides the exact amount of correction to make the round trip velocity appear to be isotropic.
yogi said:I am not quite sure what is being imputed.
yogi said:Yes - I would say that SO FAR the experiments are inconclusive. But to examine this answer further - what is it that they are inconclusive about? - if the properties of space are sui generis we don't have much of anything to base a conclusion on - physics is basically a study of relationships - For example, we don't know what an electron is in terms of something else - we know it repels other electrons, has mass and contains exactly one unit of charge - but what is charge? ..We can ask a similar question with regard to the nature of the photon ...the point being that at a fundamental level we don't have a good model of many things - so when we say there is no ether - what does that mean? This is why the question of aetheral reality is not easily answered.
yogi said:Zapper, Reality Patrol. Granted there are numerous authorities that claim there is no ether - and by their definition of ether, that is propably true. Einstein during his years of contemplation following 1905, left little doubt of his convictions on the subject as per his 1920 address. From my perspective, it is not within the spirit of science to make outright assertions that certain things exist or do not exist. It is true we can define many of the properties of electrons and photons - but are they a substantive chunk of something?... a particle is again only described by its relationship with other particles and perhaps with all other particles if you take a holistic view. I have always been fond of Einstein's comment in his letter to his lifelong friend Besso near the end of his life: "All these years of conscious brooding about the photon have brought me no closer to the truth. Nowdays every Tom, Dick and Harry thinks he knows the answer, but he is wrong."
Two points:ZapperZ said:The issue here is if there is a similar set of properties of the ether. I see different people defining it differently. The classical ether as pre 1900 clearly made several predictions. When one tries to measures these predictions and get null results, one draws one own conclusions. However, it seems nowadays that it is "fashionable" to try to redefine the ether in some other ways. So far, the ONLY consequences that I have seen coming out of such new definitions is that one cannot distinguish its presence from experiements that indicate it not being there. I don't know about you, but I find this highly dubious.
At some point, there HAS to be tangible deviations from "ether exists" and "ether does not exist". Anyone claiming that it does exist MUST make such predictions that are measureable.
yogi said:ZZ - There are challenges to "established Physics" by some very bright people. And there are others who simple don't understand why counter intuitive theories could be correct. The important thing is to be able to see which challenges, if any, have merit. We would like to think that what is printed in accepted peer reviewed literature, is true. While the laws of the universe are not going to be determined by public opinion, the direction in which we look for answers, may be.
yogi said:Reshma - Experiments don't really prove its non existence - but they cast doubt on what was once thought to be a fluid-like medium that was believed necessary for em wave propagation.
In one of my earlier post I had started to list a number of theories and experiments that are consistent with some type of spatial continuum, give it what form you will. One thing of consequence that I had not yet listed is the anisotropy of the CBR - many claim this is evidence that the Earth is traveling relative to some fixed universal background (an all pervasive ether?).
yogi said:ZZ - I really have a hard time understanding where you are coming from - your admonish me for citing references that raise questions about conventional views - you don't want me to cite anything that is not accepted in a peer reviewed journels - let's put the shoe on the other foot - what experiments and authority are you relying upon to denegrate the notion of an aethereal continuum.
Where do you get the idea that publication in a peer reviewed journel is a necessary but not sufficient condition for legitimation. I will give you a classic example of how peer reviews almost surpressed a very important breakthrough - The so called experts who where examining deBroglie's Phd thesis were of a mind to reject it - as a sort of afterthough, one of the examiners decided to send a copy of this bizaar paper dealing with matter waves to Einstein. Einstein replied: "He has lifted the corner of a great vail" The thesis was accepted. Thirteen years later debroglie was awarded a Nobel prize - the first ever granted for an academic thesis.
ZZ you have a chip on your shoulder - If you really want me to put up or shut up, offer me $100 for each article or idea I find that has been rejected by an acknowledged mainstream publication, that has turned out to be later of much value, and i will be on easy street.
You remind me of Kettering - when you take a new idea to a corporation, they tell you it won't work - then later you comeback with a model and show them it works and they say - yea - but it isn't any good - and then later you show them that it works and there is a market for it and they say - yes, its good, and it works, but we thought of it a long time ago.
Its completely understaneable: engineering is like that and that's part of why I like it. Some cocky, young engineer can think of a new way of doing something that the old engineers, who have always done it the same way, would never think of.yogi said:Russ - my experience has been just the opposite. Like you, I was an engineer - time and again I saw the new kid on the block - an engineer put on a new project that involved some technology to which he had been recently introduced - make a comment or ask a question, that led the recogonized expert(s) to change their whole perspective on something. People tend to get in a rut when it comes to thinking about things in a certain way - we have a reluctance to accept new ideas in those areas where we consider ourselves as experts - we even get hostile - its the old industrial legacy of NIH. As an Engineer you will no doubt know what those letters stand for.
russ_waters said:edit: btw, I'm a young engineer - so I don't know what NIH stands for.
yogi said:Zz I specifically stated that the deBroglie committee ultimately changed its mind - not because it had the wits within it, but because of Einstein's influence. This is an example of how a physics breakthrough almost got relegated to the circular file but for a fluke.
I happen to believe there are many good ideas that never get published because of the stance taken by mainstream physics. Of course, I would agree that theories based upon nonsense or those that defy fundamental laws should be rejected