Michelson-Morley Exp: Surprise of Result

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In summary, the Michelson-Morley experiment was designed to detect the motion of the Earth through the ether, but it yielded a null result. This was surprising because it was expected that the different motion of the Earth through the ether would have an effect on the experiment. However, the experiment's results were consistent regardless of the Earth's motion, which led to the abandonment of the classical ether theory. The idea of entrained ether or aether drag was also proposed to explain the null result, but it was inconsistent with astronomical observations and was eventually rejected.
  • #1
Paulo Figueiredo
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Hello!
Why the surprise in the result of the Michelson-Morley experiment?
If the mirrors were in earth, i think that the system is a galileu system. If the Earth is moving or if the Earth was not moving the result, in my opinion, were the same.
 
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  • #2
Think of doing the experiment using sound. Do it on the platform. Then do it on the roof of a train. Would you be surprised if the wind had no effect on the sound? In an extreme case you could do the experiment on the back of a supersonic jet - travel faster than sound and the sound could never even reach the front mirror, let alone reflect off it.

That's why Michelson and Morley were surprised by the null result. They expected the different motion of the Earth through the ether to have an effect on their experiment. But it didn't.
 
  • #3
Hello Ibix. Thanks for your answer. I understand what you have said, but are you sure that in the experiment of the supersonic jet, if the sound came of the interior of the supersonic jet, the sound never reach the front mirror? I think that the result will be that if the sound came out of the jet.
What i want to mean is that if the sound came in the interior of the jet it will be indiferent if the jet were moving (with a uniform velocity) or not.
I think that the system is a "closed" , is a galileu system...
Am i wrong?
 
  • #4
Paulo Figueiredo said:
Hello Ibix. Thanks for your answer. I understand what you have said, but are you sure that in the experiment of the supersonic jet, if the sound came of the interior of the supersonic jet, the sound never reach the front mirror? I think that the result will be that if the sound came out of the jet.
What i want to mean is that if the sound came in the interior of the jet it will be indiferent if the jet were moving (with a uniform velocity) or not.
I think that the system is a "closed" , is a galileu system...
Am i wrong?

In a supersonic jet, the "medium", which is the air, travels WITH the jet. So the air inside the jet is considered to be at rest with the interior of the jet.

This is NOT the hypothesis of the classical ether, which was thought to be the medium that light travels in. It was thought that the ether pervades the universe, and that the Earth and everything else move through the ether medium. So how fast and in what direction the Earth travels through the ether should make a difference in the speed of light that is being measured even on earth.

So the two scenarios are completely different.

Zz.
 
  • #5
Paulo Figueiredo said:
I understand what you have said, but are you sure that in the experiment of the supersonic jet, if the sound came of the interior of the supersonic jet, the sound never reach the front mirror? I think that the result will be that if the sound came out of the jet.
What i want to mean is that if the sound came in the interior of the jet it will be indiferent if the jet were moving (with a uniform velocity) or not.
I think that the system is a "closed" , is a galileu system...
Am i wrong?
I think you are referring to the aether drag hypothesis, the possibility that aether could be dragged along with the Earth's surface so that the speed of the aether "wind" would be zero at ground level. But if that were true, it would cause refractive effects, when viewing the stars, that have not been detected. See the blue link above for more details.
 
  • #6
The Michelson Morley experiment wasn't expected to be analogous to being inside the aircraft. Ether (if it existed) clearly wasn't bothered by walls - radio waves could penetrate. And Fizeau's experiments with light in flowing water weren't consistent with ordinary matter being the medium for light. Ether had to penetrate matter.

In fact, the first thought people had to explain the null result was that ether was "entrained" by matter. That is, it was dragged along with matter somehow. So then, yes, the Michelson-Morley experiment would be analogous to working inside the jet. But that's inconsistent with astronomical observations - starlight would be aberrated by parts of the ether being dragged and other parts not being.

So, no. Ether doesn't work and Newton has to be abandoned.

Edit: Beaten to it by Zz and DrGreg, I see.
 
  • #7
ZapperZ said:
In a supersonic jet, the "medium", which is the air, travels WITH the jet. So the air inside the jet is considered to be at rest with the interior of the jet.

This is NOT the hypothesis of the classical ether, which was thought to be the medium that light travels in. It was thought that the ether pervades the universe, and that the Earth and everything else move through the ether medium. So how fast and in what direction the Earth travels through the ether should make a difference in the speed of light that is being measured even on earth.

So the two scenarios are completely different.

Zz.
Thanks for your answer. I think that i understand the difference.
 
  • #8
DrGreg said:
I think you are referring to the aether drag hypothesis, the possibility that aether could be dragged along with the Earth's surface so that the speed of the aether "wind" would be zero at ground level. But if that were true, it would cause refractive effects, when viewing the stars, that have not been detected. See the blue link above for more details.
Thanks. I think i had understand the difference.
 
  • #9
Ibix said:
The Michelson Morley experiment wasn't expected to be analogous to being inside the aircraft. Ether (if it existed) clearly wasn't bothered by walls - radio waves could penetrate. And Fizeau's experiments with light in flowing water weren't consistent with ordinary matter being the medium for light. Ether had to penetrate matter.

In fact, the first thought people had to explain the null result was that ether was "entrained" by matter. That is, it was dragged along with matter somehow. So then, yes, the Michelson-Morley experiment would be analogous to working inside the jet. But that's inconsistent with astronomical observations - starlight would be aberrated by parts of the ether being dragged and other parts not being.

So, no. Ether doesn't work and Newton has to be abandoned.

Edit: Beaten to it by Zz and DrGreg, I see.
Thanks Ibix. I think that now i understand the difference.
 

FAQ: Michelson-Morley Exp: Surprise of Result

1. What is the Michelson-Morley Experiment?

The Michelson-Morley Experiment was a scientific experiment conducted in 1887 by Albert A. Michelson and Edward W. Morley to measure the relative motion of the Earth through the hypothetical "luminiferous ether" that was thought to be the medium for the propagation of light.

2. What was the purpose of the Michelson-Morley Experiment?

The purpose of the experiment was to test the theory of the "ether wind" which proposed that the Earth's motion through the ether would cause a difference in the speed of light in different directions. This was an attempt to provide evidence for the existence of the ether, which was believed to be necessary for the propagation of light.

3. What were the results of the Michelson-Morley Experiment?

The results of the experiment were surprising in that they showed no difference in the speed of light in different directions, despite the Earth's motion through the ether. This suggested that the ether did not exist, and paved the way for the development of Albert Einstein's theory of special relativity.

4. How did the Michelson-Morley Experiment influence modern science?

The Michelson-Morley Experiment marked a significant turning point in the field of physics, as it disproved the existence of the ether and challenged the long-standing belief in absolute space and time. This paved the way for the development of Einstein's theory of special relativity, which revolutionized our understanding of the fundamental laws of the universe.

5. Why is the Michelson-Morley Experiment still significant today?

The Michelson-Morley Experiment is still significant today because it played a crucial role in the development of modern physics and our understanding of the universe. It also serves as a reminder that scientific theories and beliefs are constantly evolving and can be challenged by new evidence, leading to groundbreaking discoveries and advancements in our knowledge.

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