Does Ether Exist? 19th Century Evidence

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Discussion Overview

The discussion centers around the existence of ether, a proposed medium through which light was thought to travel in the 19th century. Participants explore historical evidence, theoretical implications, and experimental challenges related to ether's existence, as well as its relevance to modern physics concepts.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that there is no evidence for the existence of ether, while others claim that the properties of empty space suggest otherwise.
  • A participant mentions the Michelson-Morley experiment as a significant historical test related to ether, noting its failure to detect ether wind.
  • There are discussions about whether modern concepts like dark energy or quantum states could be analogous to the 19th-century ether.
  • Some argue that if ether existed, it would affect planetary orbits, while others challenge this notion by stating that ether was considered massless, thus not contributing to momentum transfer.
  • One participant highlights the philosophical implications of assuming ether's non-existence, referencing Maxwell's views on energy transmission requiring a medium.
  • Another participant presents an analogy involving dry ice to illustrate how movement could be perceived in relation to ether.
  • There is a discussion about the characteristics of waves and their need for a medium, with some participants questioning the nature of sound and light waves in relation to ether.

Areas of Agreement / Disagreement

Participants express a range of views on ether's existence, with no consensus reached. Some firmly deny its existence, while others propose that ether or similar concepts may still hold relevance in modern physics.

Contextual Notes

Participants reference historical experiments and theoretical frameworks, but the discussion reveals a lack of definitive experimental proof for ether's existence or non-existence. The implications of ether on energy transmission and wave propagation remain contested.

  • #31
Nickelodeon said:
No not everything. The field round a magnet for instance. Einstein's 'spacetime continuum' :smile: the non existent aether to name but a few.

Is it wrong to think of the time-space continuum as an "ether" of sorts? If gravity can warp the t-s-c such that the path of light is changed, doesn't that mean it is "something?" And doesn't electric and magnetic fields, with their action-at-a-distance, also tend to imply "something"is carrying the fields since changes in those fields are limited to the speed of light?

Conceptually I think of time-space as a medium, if not an ether per se. While not "correct" it helps me get my head around some of the "odd" concepts in physics.

-David
 
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  • #32
About experimentation regarding my hypothesis:
If the gravitational or other fields are the medium through which light waves propagate, then there should be observational differences in the velocity of light in regions of space where gravitational fields are different; e. g., different near a strong source of gravity as compared to a weak region of gravitational fields.
The difficulty of proving this is that we live in one of those strong gravitational fields. As we move out into space we might consider repeating Michaelson-Morley or one of the experiments that grew out of their work. It may also be possible to establish something before that point using data from space missions.
Spacecraft follow trajectories that are mostly known, and communicate to Earth through radio waves, which is a form of electromagnetic radiation. These waves should behave essentially the same way that light does.
So: if we could compare the predicted position of a spacecraft with the position indicated by tracking by beacons on the craft, then we might test this hypothesis. Either the predicted point agrees with the point indicated by tracking, or it does not. If not, then the trick would be to determine if the variance is due to some other cause. If no other cause can be found, then it would seem reasonable to consider the hypothesis I've raised. I don't have that data, but it should be available from NASA, or if not, perhaps it can be gained from some future launch. Any variance between predicted and "actual" position, that identified by a tracking beacon, is simply disregarded as unimportant error, at least in my experience. I don't think data from aircraft would be usable; too much likelihood that positional errors are due to variations in atmospheric conditions. A possibility might also exist to compare "skin track" by ground-based radar with "beacon track" from an on-board beacon. Since the radar waves have to travel twice the distance through any hypothesized medium, and the beacon signal only has to travel this distance once, then there should be a variance in the two signals (after corrections in position due to light-speed lag). You would also have to eliminate any possibility of parallax due to locations of the two receivers.
 
  • #33
From Dave C: jlknapp505, you have posted a hypothesis, i.e. you are "supposing" your ideas, and they are merely ideas."
Maxwell showed the electromagnetic nature of light; presumably, that means that the electromagnetic fields around charged particles would interact with light. The only thing I hypothesized here is that, as gravity affects light, light also affects gravity. I don't think this is really revolutionary; it's just applying Newton's third law.
However, I'm not aware that anyone has ever consider this or felt that it might be important. So that's the extent of my hypothesis, that the interaction is important, and that it might be used to explain how light can have the characteristics of a wave without a medium as other waves must have.
This idea may seem trivial; but it attacks the view of light as being a constant (in vacuum), and so it throws a major monkey wrench into the gears of relativity and cosmology.
 
  • #34
DavidSullivan said:
Is it wrong to think of the time-space continuum as an "ether" of sorts?

That '"ether" of sorts" has properties completely different from the luminiferous aether of the 19th century. It would be like saying a rabbit is a giraffe of sorts. True, if you redefine rabbit and/or giraffe.

jlknapp505 said:
About experimentation regarding my hypothesis:

(Emphasis mine) Personal theories are not permitted on PF, except in the Independent Research forum.
 
  • #35
jlknapp505 said:
7. I would argue that the presence of Doppler shifting requires a medium;
Doppler shifting is completely compatible with SR and does not require a medium.
 
  • #36
I think the question here is not about the existence of an aether but, rather, is it somehow, 'stationary' and are we all 'moving through it'?

People keep referring to the Michleson Morley experiment as though it is just a bit of ancient history. Has it REALLY not been repeated with more up to date equipment? Is its conclusion really open to question? If I had access to an interferometer and some lab time, it would be one of the first things I tried to do. Surely, if it was a duff experiment, all those years ago, someone would have published a massive rebuttal by now.

So, if we really aren't moving through 'anything', why not just say we're dealing with space and move on.
 
  • #37
Michaelson-Morley has been repeated many times (see Wikipedia, among others), and variants of it have also been done using different equipment.
As to the statement that I have posted a hypothesis, I apologize if I posted it in the wrong part of the forum. I don't really consider this a "hypothesis", it's just application of known, accepted ideas (Newton, Einstein, Maxwell) in a different way. Any hypothesis is no more than applying the work of some of these so that the outcome disagrees with some of the work of others in this list.
If the moderator of this thread considers my posts misfiled, I'll be happy to move them. Note that when I posted I was replying to another series of posts regarding "aether", which is in THIS thread.
 
  • #38
jlknapp505 said:
it's just application of known, accepted ideas (Newton, Einstein, Maxwell) in a different way
The idea that the Doppler effect requires a medium is neither well known nor accepted.
 
  • #39
DavidSullivan said:
Is it wrong to think of the time-space continuum as an "ether" of sorts? If gravity can warp the t-s-c such that the path of light is changed, doesn't that mean it is "something?" And doesn't electric and magnetic fields, with their action-at-a-distance, also tend to imply "something"is carrying the fields since changes in those fields are limited to the speed of light?

Conceptually I think of time-space as a medium, if not an ether per se. While not "correct" it helps me get my head around some of the "odd" concepts in physics.

-David

I would say so. As Dalespam already stated, aether is a specific theory originating in the 19th century. The luminous aether has been more or less conclusively disproven via experimental results The aether drag was not the only consequence that would be predicted by the aether model and so even the Mickelson-Morley experiment was not enough to completely debunk the aether model (nor was it by far the only experiment of its type). As time progressed, it was continually shot down by further experimentation and required more and more complicated explanations to account for these results. In the end, the theory was not viable.

To label things as an (a)ether today is still going to carry with it the connotations and inherent properties of the original luminous aether of the 19th century theory. I think it would be far more appropriate to choose a different wording or to avoid comparisons with the aether altogether. To me, it sounds like somebody comparing an astronomical theory with geocentrism, germ theory with miasma theory.
 
  • #40
Would anisotropy of background radiation indicate "aether" on a large scale?
 
  • #41
Me thinks the good professor had his own trinity: matter, space and time. There three makes the universe. I am a heretic to claim that if the three are removed we still remain with ether. So be it.
 
  • #42
DavidSullivan said:
... Conceptually I think of time-space as a medium, if not an ether per se. While not "correct" it helps me get my head around some of the "odd" concepts in physics.

-David

I'm pretty sure that Einstein used this imagery to develop GR, whether he regarded the aether as virtual or real. He was disappointed when the MM experiment gave a null result.

That aside I don't understand why he eventually decided that should the aether exist it would make GR a nonsense. I'm sure it wouldn't, it would just mean slightly modifying things a bit and what's wrong with that?. I can't believe you would need to throw the whole GR concept out of the window.
 
  • #43
sophiecentaur said:
I think the question here is not about the existence of an aether but, rather, is it somehow, 'stationary' and are we all 'moving through it'?

People keep referring to the Michleson Morley experiment as though it is just a bit of ancient history. Has it REALLY not been repeated with more up to date equipment? Is its conclusion really open to question? If I had access to an interferometer and some lab time, it would be one of the first things I tried to do. Surely, if it was a duff experiment, all those years ago, someone would have published a massive rebuttal by now.

So, if we really aren't moving through 'anything', why not just say we're dealing with space and move on.

There's someone who is doing just that, see http://www.youtube.com/watch?v=7T0d7o8X2-E&feature=related"
If there is an aether it would appear it is moving downwards.
 
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  • #44
That youtube video shows some extremely sloppy science. He sees a result that he doesn't understand: does he check to see if there is any mundane explanation - like some mirror wiggling? No, he immediately decides that this is a Major Discovery.
 
  • #45
jlknapp505 said:
Post 3:
I didn't start out thinking about light, although it was always puzzling to me that light, or ElectroMagnetic Radiation (EMR) had all the properties of a wave but did not require a medium. But I was attempting to visualize Einstein's idea of matter "warping" the space/time continuum that surrounded it. From this I concluded that Space (I dropped the "time" part of it, at least for the moment) had to have structure or it could not "warp". So I wondered what the structure of space was. Is there, for example, something out there between the Earth, for example, and the Sun? I concluded that actually, there was something.
There was gravity and there were also numerous particles, charged and uncharged, atomic and subatomic. I began to think of space as a matrix, dense in the region surrounding planets, thin in the space between. These particles, even though of low density, nonetheless relate to each other by charge (attraction/repulsion) and they also participate in the gravitational fields that permeate all known space. The assumption here is that gravity, although relatively weak, is essentially infinite in range. The attraction simply decreases with the square of distance (Newton's inverse square law). So I wondered: does gravity affect light? The answer is yes, postulated by Einstein, confirmed experimentally. There ARE gravitational lenses.
So: if gravity affects light, does not light also affect gravity? Newton's third law requires that it does.
I then visualized the gravity within space as a kind of fluid, fluid in that it is a relationship between all masses, and that the attraction between these masses changes constantly with relative motion of the masses. I concluded that light, as energy, could cause a temporary change (very small; but then, it doesn't have to be big, it just has to exist) in this relationship. This change, propagating through the fields, is the light wave, and the fields might satisfy the requirements to be a "medium" for light.
So there it is. I look forward to your replies.

It seems logical to conclude that if space warps, then it must have a structure that defines the warping, and I tend to agree with this on a certain level but one has to be careful when defining what this structure might be. One has to keep in mind that light travels at the speed of light (c) in all frames of reference. This right here scraps the idea of an aether since moving through aether would change the speed of light which simply doesn't happen. And even though space warps, this does not imply that there is something (as we traditionally think of things) that is actually warping. The concept of warping spacetime is a mathematical construct that has analogies that we use to picture this construct. The warping rubber sheet that we are all used to is just an analogy, it is not a real thing. Light is mysterious and we don't know what it is, all we know is that it has properties that we can measure or detect, such as speed, frequency, the fact that it seems to be both a wave and particle and so on, but we don't know what light actually is. Therefore to suppose that space must be made of something so that light can move through it doesn't make sense. And to suppose that space must be made of something so it can warp also doesn't make sense because this warping is just a math construct that is used to visualize something we can't visualize. What I'm saying is that space warping may not really be happening, but it works mathematically so the analogy works on a certain level. Reality is much much stranger than we are able to visualize. All we have is analogies. In a nutshell, all I'm saying is that since we don't know what light is (or gravity is), we can't construct what we think space is based on what light does or what gravity does. We can just define relationships.
 
  • #46
Nickelodeon said:
I'm pretty sure that Einstein used this imagery to develop GR, whether he regarded the aether as virtual or real. He was disappointed when the MM experiment gave a null result.

That aside I don't understand why he eventually decided that should the aether exist it would make GR a nonsense. I'm sure it wouldn't, it would just mean slightly modifying things a bit and what's wrong with that?. I can't believe you would need to throw the whole GR concept out of the window.

Are you sure Einstean was disappointed? I thought he knew of the result before the result even came back. GR and SR is based on light being a constant in all frames of reference, so a positive result in the MM experiment would have totally halted all SR/GR theories.
 
  • #47
Nickelodeon said:
I'm pretty sure that Einstein used this imagery to develop GR, whether he regarded the aether as virtual or real. He was disappointed when the MM experiment gave a null result.

That aside I don't understand why he eventually decided that should the aether exist it would make GR a nonsense. I'm sure it wouldn't, it would just mean slightly modifying things a bit and what's wrong with that?. I can't believe you would need to throw the whole GR concept out of the window.

The Michelson-Morely experiment was conducted in 1887, that's [EDIT: sorry, I can't do arithmetic] [STRIKE]8[/STRIKE] 18 years before Einstein published his paper on SR, let alone GR, which came another 10 years after that! Your claim is blatantly wrong, and I don't understand how you could even post it. As far as I know, Einstein was only dimly aware of the results of this experiment in 1905, but it didn't matter because he saw no theoretical need for the luminiferous aether. The whole point of Special Relativity was that by rethinking certain ideas about mechanics (motion, space, and time) it was possible to show that the laws of electrodynamics were NOT inconsistent with the principle that the laws of physics should be the same for all inertial observers. (This perceived inconsistency was the only reason that others had for introducing the concept of the aether in the first place).
 
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  • #48
Um... the Michelson-Morley experiment was in 1887, when Einstein was eight years old. He was still a few years away from coming up with SR. :rolleyes:
 
  • #49
jtbell said:
Um... the Michelson-Morley experiment was in 1887, when Einstein was eight years old. He was still a few years away from coming up with SR. :rolleyes:

I don't understand. Was that in response to my post? Because it seems like you are agreeing with me and we are saying exactly the same thing (yet, you are rolling your eyes).
 
  • #50
cepheid said:
jtbell said:
Um... the Michelson-Morley experiment was in 1887, when Einstein was eight years old. He was still a few years away from coming up with SR. :rolleyes:
I don't understand. Was that in response to my post? Because it seems like you are agreeing with me and we are saying exactly the same thing (yet, you are rolling your eyes).
Check the timestamps! It looks like you both posted almost simultaneously.:smile:
 
  • #51
Yes, I was responding to Buckethead, and to Nickelodeon a few posts earlier, who made a similar comment about Einstein and the MMX.
 
  • #52
Nickelodeon said:
There's someone who is doing just that, see http://www.youtube.com/watch?v=7T0d7o8X2-E&feature=related"
If there is an aether it would appear it is moving downwards.

That is a poor demonstration as he has not attempted to discuss various experimental error. The simplest explanation would be that objects in his test setup are slightly loose and being dislocated by gravity.
 
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  • #53
Nickelodeon said:
There's someone who is doing just that, see http://www.youtube.com/watch?v=7T0d7o8X2-E&feature=related"
If there is an aether it would appear it is moving downwards.
When you say "downwards" are you referring to "towards the centre of the Earth"? Are you suggesting that it is a gravitational effect (local) or that we (Earth) happened to be moving through the Aether in that direction. But his diurnal effect was only slight, was it not? According to your idea and ignoring the gravitational effect, we should be moving 'upwards' at a time 12 hours different. I appreciate that this would only apply exactly whilst near the Equator, but my point still stands.

So it has to be a gravitational effect (?).
Sagging equipment could explain this. (One of those old-age problems),
 
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  • #54
I still don’t see how the michelson morley experiment shows that the ether doesn't exist .
I thought it showed length contraction , and this led Hendrik Lorentz to formulate Lorentz transformation. I Don’t see how this had anything to do with the ether .
 
  • #55
cragar said:
I still don’t see how the michelson morley experiment shows that the ether doesn't exist .
I thought it showed length contraction , and this led Hendrik Lorentz to formulate Lorentz transformation. I Don’t see how this had anything to do with the ether .

One of the possible consequences to an aether model is the aether wind. If there is some medium that permeates space that is propagating light, then the Earth will have a relative velocity with this medium. The velocity of the light will thus be different depending upon how the path of the light moves related to the source and receiver's relative velocity to the medium. However, the experiments (which were repeated at different directions, different times of the year and by many many different research groups) showed that the expected shifts due to the aether windwere not existent.

And to reiterate, aether wind was just one of several aspects of the aether model that have been challenged by experimental results.
 
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  • #56
cragar said:
I still don’t see how the michelson morley experiment shows that the ether doesn't exist .
I thought it showed length contraction , and this led Hendrik Lorentz to formulate Lorentz transformation. I Don’t see how this had anything to do with the ether .

One of the 'explanations' of the MM experiment results was the Lorenz Contraction - that's all. Yes, you can measure a contraction but the fuller appreciation of SR and the other relativistic effects can't be had if that's all that you consider.

My problem with the whole business of wanting an Aether is that everyone's 'personal' bit of Aether must be behaving differently - even when they're going past, close to each other, at different rates. Hanging onto conventional ideas can very often interfere with your appreciation of new ones. There are so many examples of this - the two slits experiment is another of them.
 
  • #57
Vanadium 50 said:
That youtube video shows some extremely sloppy science. He sees a result that he doesn't understand: does he check to see if there is any mundane explanation - like some mirror wiggling? No, he immediately decides that this is a Major Discovery.

Things have moved on since that video was made and he has gone to considerable lengths to minimise any mechanical errors. Apart from that, there are fringe shifts when the apparatus is static in a vertical plane over a 24 hour period but not so in a horizontal plane. Could you give an explanation for why you think that should be?
 
  • #58
sophiecentaur said:
When you say "downwards" are you referring to "towards the centre of the Earth"? Are you suggesting that it is a gravitational effect (local) or that we (Earth) happened to be moving through the Aether in that direction. But his diurnal effect was only slight, was it not? According to your idea and ignoring the gravitational effect, we should be moving 'upwards' at a time 12 hours different. I appreciate that this would only apply exactly whilst near the Equator, but my point still stands.

So it has to be a gravitational effect (?).
Sagging equipment could explain this. (One of those old-age problems),

Whatever it is, and one should perhaps not use the word aether any more, it is more likely to be accelerating towards the centre of the Earth and causing the gravity effect.
As I mentioned before, Martin Grusenick has tried to minimise any mechanical errors but the fringe shifts are quite apparent when the equipment is static in a vertical plane compared to a horizontal plane.
 
  • #59
cepheid said:
The Michelson-Morely experiment was conducted in 1887, that's [EDIT: sorry, I can't do arithmetic] [STRIKE]8[/STRIKE] 18 years before Einstein published his paper on SR, let alone GR, which came another 10 years after that! Your claim is blatantly wrong, and I don't understand how you could even post it. As far as I know, Einstein was only dimly aware of the results of this experiment in 1905, but it didn't matter because he saw no theoretical need for the luminiferous aether. The whole point of Special Relativity was that by rethinking certain ideas about mechanics (motion, space, and time) it was possible to show that the laws of electrodynamics were NOT inconsistent with the principle that the laws of physics should be the same for all inertial observers. (This perceived inconsistency was the only reason that others had for introducing the concept of the aether in the first place).

I'm trying to find where I read the article that prompted my previous post but in the meantime here is a link to an article written by Einstein in 1920 where he states "More careful reflection teaches us, however, that the special theory of relativity does not compel us to deny ether" . http://www.tu-harburg.de/rzt/rzt/it/Ether.html" .
 
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  • #60
No, but as I said back in https://www.physicsforums.com/showpost.php?p=2611230&postcount=27" it does compel us "to redefine the word 'aether' in such a way as to remove from it most of the properties usually associated with the term". The only kind of aether which is consistent with SR is a kind of aether that has properties which are consistent with there being no aether.
 
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