Why Should There Be An Aether Wind? Mm Exp.

[Mattzy]

Can the Michelson Morley experiment be considered as proof that there is no cosmic aether? The experiment gave a null result. But it seems that it had a disproportionately negative effect on the concept of an aether. It seems to me that quite pre-determined assumptions were made as to how an aether behaves around a planet - like a flowing gas in a compressive atmosphere. 

How can we say that a cosmic aether would behave in a certain way and then declare it's non existence because certain expectations were not observed? 

 

There is a lot of space within an atom, what if the aether passes through the planet? That's just one idea from a dummy like me!

What about viscosity and compressibility of the medium? (I'm only pontificating here).

 

If we can accept gamma rays, spacetime and gravity as we do - (without detectable winds but with penetrating capacity and present through spacetime) then how can we discount an aether so easily?

[Dubbelosix]

His experiment proves that there is no physical material wind. That's all.

 

Gravity is not wind, nor is is made from gravitons. Zero point fluctuations are not around long enough to produce a wind. Gravity is a medium and an aether at the same time.

[exchemist]

Can the Michelson Morley experiment be considered as proof that there is no cosmic aether? The experiment gave a null result. But it seems that it had a disproportionately negative effect on the concept of an aether. It seems to me that quite pre-determined assumptions were made as to how an aether behaves around a planet - like a flowing gas in a compressive atmosphere. 

How can we say that a cosmic aether would behave in a certain way and then declare it's non existence because certain expectations were not observed? 

 

There is a lot of space within an atom, what if the aether passes through the planet? That's just one idea from a dummy like me!

What about viscosity and compressibility of the medium? (I'm only pontificating here).

 

If we can accept gamma rays, spacetime and gravity as we do - (without detectable winds but with penetrating capacity and present through spacetime) then how can we discount an aether so easily?

My understanding is that by the time of the experiment, the main idea for the hypothesised aether was that it was not expected to flow around, or be disturbed by, objects and that it would have to permeate matter freely. So it would behave precisely as you are suggesting.

 

However if there were such an aether, the earth would be travelling through it, at varying rates, because of its orbital motion around the sun. Also, at any moment, the rate of motion through this aether in one direction would be different from the rate of motion measured in a direction at right angles. This should mean that -  if light were a disturbance in an aether medium, i.e. like waves in water -  the speed of light would be different in the two directions. This is what the experiment famously showed was not the case. 

 

That result could only be consistent with an aether that was always stationary with respect to the Earth, i.e was completely dragged along with it, so that there was no motion through it by the earth. But there were other experiments that were not consistent with this idea. 

 

The only way to rationalise all these results was that the speed of light was independent of the relative velocity of source and receiver. This, by the way is also consistent with Maxwell's equations for electromagnetic radiation (which includes light), which does not specify an aether at all, but only finite, fixed, values for the magnetic and electrical properties of space.

 

One can - and Einstein originally did - regard the curious fact that empty space has fixed electromagnetic properties as a sort of effective aether, though of a completely immaterial kind.   

Edited June 18, 2019 by exchemist

[Dubbelosix]

That's even better worded, yes. But spacetime in gravitational aether would have to be stationary in which gravitational waves are the pseudo-fluctuations of the metric. But we can detect spacetime moving, its just that there is no fundamental component into which it can drag through, except in the sense gravity makes things drag through it - detecting this can only found in a relative sense from differing gravitational fields.

[Mattzy]

Thanks exchemist. That answers it. I wonder if there could be a re-visiting of the whole idea - or maybe it has never been as damned as I thought.

I didn't know that Einstein had thought about a fixed electromagnetic aether. It goes to show how much possibility remains.

[Dubbelosix]

It was in fact Dirac first of all who pointed out electromagnetism could be ''a particulate aether.''

[Dubbelosix]

The only aether Einstein supported was the gravitational aether.

[exchemist]

Thanks exchemist. That answers it. I wonder if there could be a re-visiting of the whole idea - or maybe it has never been as damned as I thought.

I didn't know that Einstein had thought about a fixed electromagnetic aether. It goes to show how much possibility remains.

Nowadays we are brought up to accept the values of the dielectric permittivity and magnetic permeability of space as things that "just are" and so nobody talks of an aether.

 

In fact, the whole idea that EM radiation is a disturbance in a medium is unhelpful, since it immediately reintroduces all these problems of motion relative to it. And the current model works very well, with no outstanding problems to be solved, so far as I know. So personally I don't see any reason, based on today's science at any rate, why anybody would want to revisit the aether idea.

Edited June 19, 2019 by exchemist

[Dubbelosix]

Oh, but this is were the problem of detecting something which you were not looking for... The most basic idea was an aether wind, gravitational aethers leave no wind behind, we can only detect it as a ''thickness of the medium'' and I quote Einstein ''general relativity without such an aether is unthinkable.''

[Dubbelosix]

So it not only boils down to the wrong methods to detect it, it also boils down to the wrong kind of aether interpretation. 

[fahrquad]

In my humble opinion, the human mind has difficulty grasping the concept of nothingness and has invented the aether to fill that cosmic void.  There is no reason for an aether to exist and no proof of any such thing.

 

"In physics, aether theories (also known as ether theories) propose the existence of a medium, a space-filling substance or field, thought to be necessary as a transmission medium for the propagation of electromagnetic or gravitational forces. Since the development of special relativity, theories using a substantial aether fell out of use in modern physics, and are now joined by more abstract models.^[1]

This early modern aether has little in common with the aether of classical elements from which the name was borrowed. The assorted theories embody the various conceptions of this medium and substance."

 

https://en.wikipedia.org/wiki/Aether_theories

[Dubbelosix]

But space isn't nothing...

[Mattzy]

Well that seems to put the matter to bed. As I said to begin with, a null result is not a disproof. It seems to leave a 50/50 call. But if subsequent experiments have added more to the disproof then so be it and good science prevails. 

We all see in everyday life how good ideas can be snuffed out by human factors. Hopefully science is not like that - I suppose I was wondering if that might have been the case with the idea of cosmic aether.

[exchemist]

Well that seems to put the matter to bed. As I said to begin with, a null result is not a disproof. It seems to leave a 50/50 call. But if subsequent experiments have added more to the disproof then so be it and good science prevails. 

We all see in everyday life how good ideas can be snuffed out by human factors. Hopefully science is not like that - I suppose I was wondering if that might have been the case with the idea of cosmic aether.

No. It turned out to be bad idea, leading to inescapable contradictions, not a good one. Science does snuff out bad ideas, thank goodness, though it can take a while. But then again we often see in the history of science the wheel turning, if not full circle then partly so. Who knows what our model will be in another two centuries.

 

It is always important to keep a slight distance from all these theories and remember they are models that work (i.e. fit the observations) but cannot claim to be any kind of absolute or final "truth" about nature.  

[GAHD]

The definition of an aether/ether is what makes it all break down. The word is borrowed as a kluge to describe some really funky stuff and does not quite fit our natural intuition.

The thing is, general relativity started to describe space as an ether which is kinda funny. Modern physics facilities like LIGO start to add to that since they aim to measure what is essentially an ether distortion, and a good chunk of what goes on in ATLAS and CMS is effectively attempts to make an ether-analog crack like a bat hitting a chunk of glass. Maybe firecracker in a frozen lake is a better mental image for that one. In all those cases the analogies are...imprecise at best.

So really, the nomenclature "ether" is out of common use because it's clumsy wording, the ideas behind it are mostly thrown out but some have been recycled a couple orders of magnitude downwards(or upwards) under different names. Tesla seemed to consider an ether as an important transmission medium, some models use virtual particles as an analog for that very same mechanism.

It's like exchemist so wonderfully put: they are models that work
and an unspoken addendum: ...until they stop working.

Newtonian mechanics is fine for almost everything you're likely to run into, but it stops working at the hazy edges. Quantum mechanics is fine for a few things you either have in your pocket or casually glance at in your daily life, but it stops working when you look up or turn the ignition on a '69 charger. Polarizing sunglasses work great and as you expect till you use n+2 of them at angles then things get weird. Ether works for some things too, it just doesn't usually work "better" than other dogma IMHO.

[fahrquad]

"It's like exchemist so wonderfully put: they are models that work
and an unspoken addendum: ...until they stop working."

 

Isn't that within the margin of error?

[sluggo]

Events don't move. If they did, there couldn't be 'invariant intervals'.

Events fixed in space are equivalent to a 'fixed ether', and why SR works without an ether.

In the 1920 speech at Leiden, Einstein was in favor of an ether for GR, but without any special properties such as those defined for the ether of 1900. He also reconsidered electromagnetic fields as a fundamental form of energy independent of a medium.

The Lorentz ether is another example of human analysis interpreting new things in terms of known established things. A plumber could describe electricity in terms of fluid dynamics, but that doesn't mean electricity is water. Reminds me of a slogan, 'bricks are not made from smaller bricks'.