ghwellsjr said:
Everytime I click on the video link, I get a different set of videos so I"m not sure which is the one you want but I think it is the one with the serial number XavC4w_Y9b8.
My comments will be with regard to that video. You have to pay real close attention to what they said. They never said that MMX proved that ether does not exist. At around 6:50 into the video they said "in complete disagreement with the idea of Earth moving through the ether". Then at 7:15 they say "the experiment had failed to detect the ether". This is different than saying they proved the ether does not exist.
As I said earlier, Einstein showed that no matter what inertial state they were in, they could consider themselves to be at rest with the respect to the ether. So the experiment would have the same result even if they were in a legitimate IRF but I'd hate to be around all the mercury in a weightless environment.
I think I'm totally missing the significance of your question.
ash64449 said:
You are correct. That video does very clearly state that the M&M "experiment allows us to conclude that the ether frame does not exist". However, that is not a correct conclusion. This video is full of errors and I would classify it as pure propaganda.
For example, they state that the two legs of the experiment are the same length and only when the light travels exactly the same distance for the two paths taking exactly the same time will there be no interference. If light travels at different speeds in the two legs, then an interference pattern will be observed, they claim. This is totally wrong. First off, it's impossible to make the two legs exactly the same and even if they did, there would still be an interference pattern. (It's called an interferometer.) So in reality, what M&M were concerned about is whether the interference pattern changes while the apparatus floating on the mercury is slowly rotated.
Even the other video gets this wrong. They said there should be a bright spot in the middle of the pattern if the light signals take the same time and constructively interfere and a dark spot in the middle if the beams take a different time and destructively interfere. Total nonsense.
Notice another really significant difference between the two videos. In the one you preferred, they made the statement that if the apparatus were moving along the direction of the initial beam, then the beam would take longer along the perpendicular path because it had longer to go due to Pythagorean triangle. The other video says that the parallel path is the one that takes longer (they are correct).
So you can't trust popular explanations just because they make snazzy videos.
ash64449 said:
I would like to understand this: Since Earth is moving, time slows down(moving with respect to observer who is outside the earth). When time slows down, There will be change in simultaneous events. Like they conducted experiment like this: They sent a beam,splits into two when encountered beam splitter (I think that is a beam splitter) One travels perpendicular to it,other goes straight.they too hit the two mirrors at the same time and come back to the beam splitter. This happened to them. So i wanted to ask this: Will those two split light hit the two mirrors at the same time in reference to observer outside Earth's orbit? But i think even this happens,it will reach the beam split mirror at the same time.
It is not important to determine the simultaneity of the light beams hitting the various mirrors and beam splitter. We cannot know that information. The only thing that is important is whether the interference pattern changes as the apparatus is rotated. And as long as the experiment is conducted close to an inertial state, the pattern does not change enough to notice. It wouldn't make any difference if the apparatus were traveling at 0.999c with respect to the proposed ether or at rest in the ether.
As I said before, prior to Einstein, Lorentz and others explained the null result by claiming that the lengths of things contracted along the direction of motion through the ether and that's why they did not detect any change in the interference pattern but Einstein pointed out that they could just as easily consider the apparatus to be stationary in the ether and experience no length contraction whereas anything that was "actually" stationary in the ether would be length contracted.
Remember what you learned from DaleSpam? All the effects of Special Relativity are "vice versa" and it doesn't matter which frame you consider to be your rest frame so if you pick one in which the apparatus is at rest, there will be no length contraction. Got it?