What was the role of frequency in the Michelson-Morley experiment's null result?

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In summary, the Michelson-Morley experiment aimed to detect the presence of the "aether" by measuring differences in light speed in perpendicular directions. The role of frequency was crucial, as the experiment's design assumed that light would travel at different speeds depending on the Earth's motion through the aether. However, the null result indicated no significant difference in light speed, leading to the conclusion that the aether did not exist and paving the way for the development of Einstein's theory of relativity, which redefined the understanding of light propagation independent of frequency variations due to motion.
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Does the proportional relationship between frequency, wavelength, and light speed offer a simple explanation of the Michelson-Morley experiment's null result?
The Michelson-Morley experiment (MMX) was set up to detect an effect associated with the luminiferous ether, a substance that doesn't exist. On the other hand unmoving space does exist in the sense that a spectrometer can be placed in a position where it doesn't detect Doppler redshifts or blueshifts from the cosmic microwave background (CMB). Anchored at the position of this spectrometer a coordinate system can be drawn that provides a standard reference frame against which the speeds of light and their sources can be measured relative to this position. Then this question, without an ether to slow the light from the moving source, wouldn't there still be a fringe shift in the direction of earth's motion? The unrestricted light in that direction would travel at c+v, while the light in the perpendicular direction would travel at c + a transverse velocity component, but slower, exactly the inverse of the MMX expectation. Even so, the two rays still united with perfect precision at the instrument focus. What in the relationship of frequency, wavelength and speed between the two rays in their journey through their moving light paths traveling through the Doppler-neutral coordinate system of the CMB, could explain how one ray moving faster could match the other going slower?

My guess is the relationship between lightspeed (c), wavelength (lambda), and frequency (f) is found in the equation, c divided by lambda equals f. With units of distance and time of centimeters (cm) and nanoseconds (ns), for MMX, c is 30.0 cm/ns, and v is 0.003 cm/ns. To solve for frequency, f(lab), as it was in the MMX lab, I set f(lab) equal to 30.0 cm/ns divided by 0.00006 cm, the wavelength of the MMX ray, and found the ray's frequency, 500,000 beats per ns. Since the lab was moving, its light source was sending wavelengths at the speed c+v relative to a coordinate system anchored at rest with the CMB. To find how long wavelengths would be in the unmoving coordinate system compared to the moving coordinate system I set lambda(CMB) equal to (c+v) divided by f(lab), 30.003 cm/ns divided by 500,000 beats per ns. Out popped the length of lambda(CMB), 0.000060006 cm.

The result could be an interference pattern identical to the pattern created when the source isn't moving. In other words, even though one ray is moving faster relative to a position Doppler-neutral to the CMB, lambda(CMB) traveling at c+v would match the frequency of lambda(lab) traveling at c, 500,000 beats per ns. Light traveling at 30.003 cm/ns divided by 0.000060006 cm is 500,000 beats per ns, the same frequency as in the lab. It also means each ray's wavelength takes the same time to transit its wavelength as the other ray transits its wavelength. 0.000060006 cm divided by 30.003 cm/ns, (lambda(CMB)/(c+v)), is 0.000002 ns. And 0.00006 cm divided by 30.0 cm/ns is also 0.000002 ns. The longer wave moving faster hurries into the shorter wave moving slower producing an interference pattern the same as if each wave was the same length traveling at the same speed. Thus in both coordinate systems, the one anchored in the Doppler-neutral to the CMB position and the one traveling with the earth through that system MMX produced a null result. In the light of this simple elaboration of the role of frequency in the MMX null result, what is the necessity of the Einstein-Lorentz transformation?
 
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MrYes said:
what is the necessity of the Einstein-Lorentz transformation?
You can find non-relativistic models to which the Michelson-Morley experiment is blind, sure. But you also have to explain the Ives-Stillwell experiment, Fizeau's experiments with light in water, double star results, nuclear energy, explain why electromagnetic theory works at all, ditto all quantum field theories, derive a new theory of gravity consistent with general relativity everywhere it's been tested but somehow not Lorentz-covariant (including explaining the cosmic microwave background, by the way), and more.

Quite a lot follows from the Lorentz transforms, backed by a huge body of experimental data. You can't just throw them out because there are other models that are consistent with Michelson-Morley.
 
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MrYes said:
My guess is
Personal speculations are off limits for discussion here. There is voluminous literature on the MM experiment and its theoretical implications, going all the way back to the 1890s.
 
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The response by @Ibix in post #2 is more than sufficient. This thread is closed.
 

FAQ: What was the role of frequency in the Michelson-Morley experiment's null result?

What was the Michelson-Morley experiment?

The Michelson-Morley experiment, conducted in 1887 by Albert A. Michelson and Edward W. Morley, aimed to detect the presence of the "aether," a medium through which light was thought to travel. The experiment used an interferometer to compare the speed of light in perpendicular directions, expecting to find a difference due to Earth's motion through the aether. However, it resulted in a null result, showing no significant difference in the speed of light regardless of direction.

How was frequency involved in the Michelson-Morley experiment?

Frequency played an indirect role in the Michelson-Morley experiment. The experiment relied on the interference patterns of light waves, which are a function of the light's frequency. By using a monochromatic light source, the experimenters ensured that the interference patterns would be stable and measurable. Any shift in these patterns would indicate a change in the speed of light due to the aether wind, but no such shift was observed.

Why did the Michelson-Morley experiment result in a null result?

The null result of the Michelson-Morley experiment indicated that there was no detectable difference in the speed of light in different directions. This contradicted the aether theory, which predicted such a difference. The null result can be explained by the principle of the constancy of the speed of light, later incorporated into Einstein's theory of special relativity, which states that the speed of light is constant in all inertial frames of reference, regardless of the motion of the source or observer.

Did the frequency of light affect the outcome of the Michelson-Morley experiment?

The frequency of light did not affect the outcome in terms of the null result. The experiment was designed to detect differences in the speed of light, not changes in frequency. However, using a monochromatic light source with a stable frequency was crucial for producing clear and stable interference patterns, which were essential for accurately measuring any potential differences in the speed of light.

What implications did the null result have for the concept of aether?

The null result of the Michelson-Morley experiment had profound implications for the concept of aether. It suggested that the aether, as a medium for the propagation of light waves, did not exist. This finding paved the way for the development of modern physics, particularly Einstein's theory of special relativity, which eliminated the need for aether and introduced the idea that the speed of light is a fundamental constant of nature.

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