Did Michelson-Morley experiment prove there was no Aether or that there was no "Aether-wind"

[Achilles]

Also how accurate was the experiment?

[beecee]

36 minutes ago, Achilles said:

Also how accurate was the experiment?

The Micheson/Morley experiment was conducted to show that the ether [the medium thought to be needed for light to traverse in] did exist. It failed and showed that no medium did exist.

The experiment done at that time was the most accurate available. But of course like all scientific experiments, they are continually repeated.

https://physicsworld.com/a/michelson-morley-experiment-is-best-yet/

Michelson–Morley experiment is best yet

14 Sep 2009 

"Physicists in Germany have performed the most precise Michelson-Morley experiment to date, confirming that the speed of light is the same in all directions. The experiment, which involves rotating two optical cavities, is about 10 times more precise than previous experiments – and a hundred million times more precise than Michelson and Morley’s 1887 measurement.

The laws of physics appear to be the same for all processes occurring in laboratories moving at constant speed and for any orientation – a fundamental concept known as Lorentz symmetry. It takes its name from the Dutch physicist Hendrik Antoon Lorentz, who was attempting to explain the null result of Albert Michelson and Edward Morley’s famous experiment. Then in 1905, Albert Einstein used Lorentz symmetry as a postulate of his special theory of relativity.

Lorentz symmetry has so far withstood the tests of time, but in recent years physicists have begun to question whether it is indeed an exact symmetry of nature. They are motivated primarily by the development of string and loop quantum gravity theories, which try to make gravity compatible with quantum physics and allow for the possibility that Lorentz symmetry might not hold exactly.

In order to develop these and other theories, physicists need to know if and when the speed of light is different in different directions. Michelson and Morley tackled this problem by splitting light into two beams that travel at right angles to each other, are reflected by mirrors and then recombined with each other to produce an interference pattern, which depends on different lengths of the two paths. A change in this pattern as the interferometer is rotated would suggest that the speed of light is different in different directions."

more at link.

Edited August 24, 2018 by beecee

[Janus]

It showed that there was no detectable ether.  The "aether wind" it was looking would have been the result of the Earth moving with respect to the aether.

Of course, there would have been no wind if the Earth was at rest with respect to the aether.   However, the Earth orbits the Sun in a circle, and thus it would only be possible for it to be at rest with respect to the aether  at one particular time of the year. Since the experiment gives the same result no matter what time of the year it is performed, this is not an option.

As to accuracy, it was accurate enough to detect the expected motion with respect to the aether, if it existed.  But the accuracy of the original experiment is moot as it has been repeated since to much higher degrees of accuracy without giving any different results.

I know that there are some out there that seem to think that if they could just find some flaw in the original M&M experiment, the whole of Relativity would come crashing down to its foundations.   This simply is not the case.  Relativity is supported by so many various and independent experiments and observations that it is far too late to put that particular genie back into its bottle.

For instance,  It has been suggested that Mendel "fudged" some the result for his Pea breeding experiments, as they were just a bit too perfect.   But even if he had, it wouldn't have changed the validity of the Laws of genetics he discovered.

 

 

[John Cuthber]

The original experiment would have have given a positive result if the speed of the Earth through the ether was only 3km/sec or about  a tenth of that calculated from the Earth's orbit round the Sun.
What they didn't recognise at the time that the Earth's movement round the milky way is much faster and the experiment - all those years ago- was therefore about 7 times more sensitive than they thought it was. (I'm thinking of repeating the experiment in  my garden; with luck I might get a significant null result at this level)

 

Current tests are such that they would detect the ether "wind" if it was passing by at a few nanometres per second. 

https://en.wikipedia.org/wiki/Michelson–Morley_experiment#Recent_optical_resonator_experiments

[swansont]

And people often forget that Bradley measured stellar aberration ca 1725, so we already knew we were not at rest with any purported aether. M-M would have fully expected to confirm a ~30 km/s number.

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

[Janus]

3 hours ago, swansont said:

And people often forget that Bradley measured stellar aberration ca 1725, so we already knew we were not at rest with any purported aether. M-M would have fully expected to confirm a ~30 km/s number.

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

And which also rules out the other offered explanation of "Aether Drag", where it is suggested that the Earth carries a bubble of aether around with it as it orbits the Sun.

[neuerwind]

On 25.08.2018 at 3:38 PM, swansont said:

And people often forget that Bradley measured stellar aberration ca 1725, so we already knew we were not at rest with any purported aether. M-M would have fully expected to confirm a ~30 km/s number.

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

Well, by your logic, we are certainly not at rest. We are moving 30 km/s around the sun and about 220 km/s around the center of galaxy (together with the solar system).

Now, a million dollar question: why the star aberration does not take into account that 220 km/s of speed? That's helluva lot of speed

Edited August 27, 2018 by neuerwind

[beecee]

49 minutes ago, neuerwind said:

Now, a million dollar question: why the star aberration does not take into account that 220 km/s of speed? That's helluva lot of speed

Perhasp some knowledge of physics and everyday observation of say a passenger jet going at 600 kms/hr, and stellar aberration and paralex. 

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

https://www.google.com.au/search?q=stellar+paralex&oq=stellar+paralex&aqs=chrome..69i57j0l5.7327j1j7&sourceid=chrome&ie=UTF-8

Edited August 27, 2018 by beecee