existence of the aether model (1 Viewer)

[Sirius Black]

My teacher said we cannot simply say that the null result of Michelson-Morley's experiment disproved the existence of aether model as it just FAILED to find any evidence of aether's existence. However, Einstein's first postulate says that "the laws of physics are the same in all frames of reference." thus the principle of relativity cannot be violated by optical experiments. Didn't this imply that aether does not exist?
(altho the existence of aether model does not matter now, i'm still keen to the know whether it exists or not?)

 

[rnitya_25]

aether is a medium that light needs to travel through, and because the michelson morley experiment proved that light does not need a medium to travel through, nor does it get affected by the aether wind, aether does not exist.

 

[rama_v]

My teacher said we cannot simply say that the null result of Michelson-Morley's experiment disproved the existence of aether model as it just FAILED to find any evidence of aether's existence. However, Einstein's first postulate says that "the laws of physics are the same in all frames of reference." thus the principle of relativity cannot be violated by optical experiments. Didn't this imply that aether does not exist?
(altho the existence of aether model does not matter now, i'm still keen to the know whether it exists or not?)

See I am confused at to what the sylabus actually requires. To me, the Michelson Morley experiment was simply a null result - it did not prove that the aether did not exist. However some text books say the result was that it did indeed disprove the aether theory and that the aether theory was discarded (this is not really true from what I have read, some ppl still believe there could be an aether). Einstein's model simply states that the aether is 'not required' although I like your idea about relativity not being violated by optical experiments.

So basically it comes down to what the sylabus writers want us to conlude - either
(1) The experiment was a null result and did not necessarily disprove the aether
(2) The aether did not exist.

which one is it?

 

[speed2]

according 2 my teacher u can't prove a negative, hence can not prove that aether does not exist so it has to be (1) The experiment was a null result and did not necessarily disprove the aether.

 

[Jago]

aether is a medium that light needs to travel through, and because the michelson morley experiment proved that light does not need a medium to travel through, nor does it get affected by the aether wind, aether does not exist.

einstein's theory did not disprove the existence of aether.

im sure they want us come to conclusion 1

 

[Sirius Black]

according 2 my teacher u can't prove a negative, hence can not prove that aether does not exist so it has to be (1) The experiment was a null result and did not necessarily disprove the aether.

I agree with u, speed2

 

[rama_v]

einstein's theory did not disprove the existence of aether.

im sure they want us come to conclusion 1

Yeah, I would agree with (1)

 

[crazy_viet]

the aether model =S

can someone please explain the difference between these two dot points...

- Describe and evaluate the Michelson-Morley attempt to measure the relative velocity of the earth through the aether

AND

- Discuss the role of the Michelson-Morley experiments in making determinations about competing theories


THANKS! btw good luck year 12 2005! go good to scale me up please! xD

 

[redruM]

this is from my notes way back when i did the hsc. hope it helps. (i dont guarantee its usefulness)


[-DESCRIBE & EVALUATE-]
• Michelson-Morley attempt to measure the relative velocity of the Earth through the aether
- Since the Earth was moving relative to the aether, it was thought that there would be an aether wind [think of Earth as a car driving through air].
- The speed of sound in still air isn’t influenced by it. However, if the air is blowing, the speed of sound would vary for an observer. Similarly, the speed of light would have to vary, due to the aether wind.
- The experiment was set-up in a manner that would detect this difference.
- A ray of light was split by a half-silvered mirror. One went through it and one bounced off at 900. After reflecting, the rays came back to the half-silvered mirror and this time again, rays from both mirrors either went through or reflected towards the observing interferometer. The interferometer was sensitive enough to detect the expected interference.
- No interference or discrepancies between the periods of the two split rays was detected.
- The experimental set-up was rotated 900, performed at different heights, yet the ‘null result’ was consistent.

[-DISCUSS-]
• Role of the Michelson-Morley experiments in making determinations about the wave model of light
- The experiment was based on the aether model and was set out to measure the speed of Earth through the aether. The ‘null result’ showed that the aether model was untrue.
- Experiments were done to validate the hypothesis. Since that failed, this prompted the proposal of an alternative hypothesis.
- Many scientists tried to hold on to the aether model by suggesting that a large object, like Earth, would drag the aether with it. But, these modifications didn’t qualify.
- 20 years after the experiment, Einstein proposed his theory of relativity, which didn’t require the aether model.
- This led the scientists towards to options; try to modify the aether model and prove it or follow Einstein’s theory of relativity.

 

[speed2]

well, for (1) u just talk about the experiment (method...) and say it's result was a null-result

for (2) you talk about the modifications of the aether model that were proposed, lyk dat the aether was stuck to the earth, length contracted in the direction of the aether wind...

hope dat helps

EDIT: most of wat redrum said, except that the null-result DID NOT show that the aether did not exist

gud luk 2 u 2 buddy

 

[Xayma]

Einstein's theory (well mostly maxwell's equations) just said that there was no need for an aether. It could be there, but if it isn't everything will still work according to those equations (that isn't to say that those equations by Einstein are 100% correct, and small modifications might be needed that require an aether).

 

[derrida]

"My teacher said we cannot simply say that the null result of Michelson-Morley's experiment disproved the existence of aether model as it just FAILED to find any evidence of aether's existence"

Yes, that means because the Experiment found a null result, doesnt not mean the aether doesn't exits.

It could be a problem with the apparatus!

However, the most likely conclusion from this experiment, is that the Aether does not exist.

Hence why we believe the Aether doesn't exist!

 

[Xenocide]

If Einstein's 'Special Relativity' is right, there is no natural rest-frame in the universe. Therefore, there can be no "aether" as it is commonly known, because if there were, it would provide the natural rest frame, and affect the speed of light as measured in other moving inertial frames (read: the speed of light would become RELATIVE not CONSTANT).

In summation;

- the aether CAN exist, but CANNOT provide an absolute frame of reference.

It is the synthesis of these two facts that leads to the idea that

- the aether is superfluous

If this still isn't clear speak up .

 

[ark]

Absence of evidence is not an evidence of absence...
and the new way of spelling aether is ether now, they changed it back to the original way but not that it matters.

How did Einstein interpret the negative result of the experiment??

Einstein developed a potulate for his theory of relativity that places quite different interpretation on these null results. He proves that the speed of light is constant in ALL FRAMES OF REFERENCE. Light is now understood as E.M.R. which requires NO MEDIUM for it to travel in. So Einstein had shown the existence of ether was not needed to explain the properties of light.

answer to your question is (which was answered in above post but...) the ether model was NOT dis-proved.

 

[serge]

He proves that the speed of light is constant in ALL FRAMES OF REFERENCE.

He didnt prove it himself did he?
I thought he hypothesised it and then someone else proved it years later?
I dont think he actually used a real (instead of 'thought') experiment to prove this

 

[Xenocide]

Serge:

If his theory was correct, then Einstein did in fact prove the speed of light was constant. Results and predictions based on his theory were later VERIFIED by experiments which lends to the belief that his theory is correct (or needs only minor refinement).

 

[Xenocide]

Ark:

please let me know where i go wrong:

(1) The ether was a proposed medium for light which had the KEY property of being an ABSOLUTE reference frame

(2) Einstein proved that the speed of light was constant

These two statements are fundamentally incompatible. If there was an ansolute frame of reference, then light would only have a speed RELATIVE to the ether and would no longer be constant.

In summation, there are 2 options that are possible:

1) Einsteing was wrong about the speed of light and subsequent experiments also gave erroneous results

2) The ether exists, but does not have the property of being an ansolute frame of reference

If 1) is true.... we are in some trouble.

If 2) is true then where is the point in theorising an ether anyway (read: it become superflous)

(note: there is a third property which involved the aether having properties that closely mimic special relativity, but that is just silly)

 

[serge]

Serge:

If his theory was correct, then Einstein did in fact prove the speed of light was constant. Results and predictions based on his theory were later VERIFIED by experiments which lends to the belief that his theory is correct (or needs only minor refinement).

Im just thinking, using De Broglie as an example...
De Broglie hypothesised matter had wavelike properties
but they also teach us that it was Davisson and Germer
that showed it was true with their nickel experiment,
you know what i mean

 

[Xenocide]

I see your point. A better answer would be that there is never any proof in physics. People (such as Einstein and De Broglie) make hypothesis' and then experiments provide support for or against these ideological frameworks.

 

[serge]

oooh... getting philosophical there
(i get what you mean)