Comparison of Special Relativity with a Galilean "preferred frame" theory

Yes, whereas PF isn't.

 

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James R: Joke: If you were trolling for people who have no clue about SR, GR, & the implications of the Michaelson-Morley experiment, you were successful.

Perhaps it might help some of them to understand the basis of Special Relativity if the history of the MM experiment were explained. MM were the first to accurately measure the speed of light.

Their methods are not important to this discussion. Anyone interested in the apparatus used can find it via a Web search.

After their initial work, MM built a similar apparatus on a surface which could be tilted & rotated. Classical physics predicted that light traveled relative to an absolute coordinate system. By measuring the speed of light many times with the apparatus tilted & rotated to many different orientations, they expected to determine the speed & direction of the Earth’s motion relative to that absolute coordinate system.

No matter how they oriented the apparatus, the measured speed of light was the same. They knew that the Earth's orbital speed was circa 66,000 MPH & that their measurements were accurate enough to detect this motion. This implied one of the following explanations.

The Earth is stationary & perhaps at the center of the universe as claimed by various religious theologies.

The current (circa 1885) laws of physics are seriously flawed.​

In Galileo’s era, the first explanation would be accepted by most people. Circa 1885, the second explanation was assumed to be correct. For circa 20 years, the situation was considered a serious problem with no explanation.

BTW: My father told me about two other known problems at that time.

Obler’s paradox: Cosmology of that era predicted that the Earth should be incinerated by an unbounded amount of starlight. A Web search will provide the details.

The sun was known to have been producing a large amount of energy for long enough to have exhausted any fuel source imaginable at that time.​

Einstein in 1905 published three significant papers. The one relating to Special Relativity provided news laws of physics based on the MM experiments.

Other developments explained the other two apparent anomalies.

 

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That's not a joke it's a troll. Dinoboor.

 

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I thought they went to great lengths inorder to keep the experiment perfectly level so that the curvature of the light due to Earths gravitation wouldn't affect the experiment.

 

BTW, I think the title of this thread is incorrect. Galileo was the one that came up with the basis of relativity and did away with the absolute frame, Einstein just used Galilean Relativity in his own theory. So I don't know what you mean by a Galilean preferred frame, unless you mean to say that he also came up with the idea of an absolute frame when he discovered that there wasn't one. Although, I don't think Galileo really came up with the idea of an absolute frame.

 

Hey James, neither Galilean nor Minkowskian has a preferred frame. The difference of the transformation between frames.

There is also one and only one other similarity between both types of transformations.

 

If velocity is length over time, consider carefully how we establish length and time. Ultimately the "clocking rate" of clocks and the "length" of rulers depends upon the propagation of photons and other force carriers...all which have a velocity of c. Measuring c by a standard of c is equivalent to measuring the length of an object's shadow by the shadow of an adjacent ruler; we're going to get the same answer no matter how long the object's shadow actually is.

 

Nope they were completely unconcerned about the affects of gravity on the light. Einstein had not developed the theory of GR at that point so it was not known that gravity curved space.

 

You should reread the OP.

 

But here, James R is not speaking about just models of space time, but about physics. And the first comprehensive theory of electromagnetism predicts that light, in vacuum, travels at a fixed speed. \({ \Large c } \quad = \quad { \Large \frac{1}{\sqrt{\varepsilon_0 \mu_0}} } \quad = \quad 299,792,458 \; \textrm{m} \cdot \textrm{s}^{\tiny -1}\) This result is not compatible with a space time where inertial coordinate frames are connected by Galilean transforms unless you assume that this speed only is measured in a preferred inertial coordinate frame.

 

true. But general consensus is against ballistic theory

 

Can someone please tell me what the equation \({ \Large c } \quad = \quad { \Large \frac{1}{\sqrt{\varepsilon_0 \mu_0}} } \quad = \quad 299,792,458 \; \textrm{m} \cdot \textrm{s}^{\tiny -1}\) is called?

 

For any experiment conducted in the local proper frame, Lab frame, the local coordinate speed of light is invariant. You're trying to say we can't know that for sure. Measurements made in local proper frames, Lab frame, are invariant. This means measurements for distance and tick rates are invariant. The same for all local proper frames. The reason is local proper frame, Lab frame, spacetime is 'essentially' flat. The spacetime of SR. IE any effect due to gravity is so small it doesn't change the experimental measurement in a meaningful way. One experiment where this isn't true is the GPS where we had to account for delta tick rate in the nanosecond range. The following is the remote coordinate speed of light which isn't invariant

dr/dt = 1-2M/r

The LIGO experimental apparatus is the Lab frame. They use the speed of light to detect movement in the test mass. Locally the movement would be explained as the test mass moving because the local coordinate speed of light is invariant. From remote coordinates you can explain the change as a miniscule change in the remote coordinate speed of light.

The first indication that the local coordinate speed of light is invariant is covered in rpenner's post.

 

I don't understand your point here. I'm not claiming that c isn't invariant, I'm providing a reason why c might appear that way. And I'm suggesting that c might appear invariant even in a PF world, only because any changes in it would result in changes in the results of our measuring devices as well. If you want to claim that such a world does not qualify as a true PF in this particular thread because of the PF2 postulate, then I would agree.

 

No they don't. A ruler is just an arbitrary piece of material, sitting still, doing nothing. There are no forces (propagating or otherwise) at work in fixing its length. And even if there were, since the lengths of the arms are arbitrary (but equal), the actual length isn't very important for making the experiment work.

A cesium clock measures the frequency of radiation given off by excited atoms. It does not depend of forces either. Perhaps you're confusing that with a wind-up mechanical clock.

 

There are no forces at work, but as RJB said, the observed "length" of the ruler is not always the same as the length it has at rest - depending on the observer's frame. Nothing physical has changed about the ruler even though different observers see different lengths.

 

I know this experiment was before Einstein published his theory, but he also claimed that he did not know anything about this experiment and did not base his theories on it. It is possible that they could have thought it would just be pulled by gravity like any other object. So then they wouldn't have had to have known about Einsteins curved space. I would think that since light does curve in the precense of gravity that it would have had an effect on the experiment. Plus, I have read that they did go to great lengths to balance the experiment for this reason. Do you have a source that backs up these claims? If you are right then the M&M experiment could not have been that accurate, but I think it was fairly accurate because of the way they compare the speeds of the beams by matching up the wavelengths.

 

A ruler is most certainly not sitting still. It's a dynamic, jiggling collection of wood and paint molecules doing a dance, appearing to be perfectly balanced between each other via EM and other forces.

 

Trollolololol, maybe you should reread the statement you just replied too. Or you could read this link and then discover that the preferred frame is actually Newtonian, not Galilean.

http://en.wikipedia.org/wiki/Galilean_invariance

So the title of this thread should be, Comparison of Special Relativity with a Newtonian "preferred frame" theory

 

Has the following equation got a name? \({ \Large c } \quad = \quad { \Large \frac{1}{\sqrt{\varepsilon_0 \mu_0}} } \quad \) What is it called?