Originally the aether was thought to exist, but it was hoped the earth would move though it rather than entrain it, maybe as a continued departure from earth centric thinking, or more likely because a static aether was far more simple than trying to understand an aether that was entrained to some degree by Earth.
First Michelson and Morley performed an experiment which if not flawed (some say it is) would show if the earth moved though an aether, however such was not detected. However this did not disprove an entrained aether, Michelson and or Morley still believed in an aether. Indeed drifts with the M-M experiment were detected, just really tiny ones consistent with with a mostly entrained aether, but larger drifts have been detected up mountains in glass houses than in brick basements where aether might be more poorly entrained. Next came Einstein with SR, he showed how an aether wasn't required if space and time distorted in the right ways. Actually he still believed in an aether, although a very different one. Let's look at Time dilation. First off I must say that SR arguments works and look alright until you change your view slightly. Let's take a pulse of light, some observers on the ground measuring the time this pulse takes to traverse 2 detectors 1 meter apart, they get a speed of 299,292.458 meters a second. Then we have have this pulse run along train tracks past a train, they detect this light pulse which they are moving with, and they are meant to detect the same speed. This is an impossibility, except for length contraction and time dilation, only it is still impossible! The first thing to appreciate is that there is an illusion that will appear to create length contraction and time dilation, but this illusion is not real at all. It is the Doppler effect, consider that if I was shooting at you and moving towards you, each bullet would have less travel time causing an increase in the rate at which I seem to be firing bullets, this is the same effect as pitch changes in horns as cars go by. If I was moving away from you it would appear the rate of fire decreased. But of course the rate of fire is unchanged This will create an illusion of the rate of time, but this illusion can be removed through calculation, or by communication of time rate orthogonally to direction of travel. a b-> c b is moving away from a, but both a and b can sync clocks with c. since b and c have a period where they are not moving away or toward each other they can keep track of each others progress through time without and Doppler effects in the way. Secondly the Doppler effect causes a length contraction (and expansion) illusion, this is where at any moment a sees b, it sees light from different points in time and hence different positions for the closer and furthest part of b. Because the light from the furthest part of b takes longer to get to a, by the time it has got to a the image a has of the closer portion of the ship is slightly newer and based on a position further away. This causes an illusion of length contraction, but for c this length contraction also has not occurred. And if we add 'stationary' point d that b is moving towards it would see a length expansion which SR ignores completely. So if there is real time and length contraction it is important to separate that from this bogus, illusive form of these effects. And it is important to realise that observer c collapses any possibility of time dilation occurring without a preferred reference frame, if a time rate difference exists between b and c it can be agreed upon between both b and c, they can't see the other as experiencing time slower than they are because they can observe each other without the Doppler distortion, if they both saw the other as frozen in time what happens if they both reach a common reference frame, and meet, would they have to see the time rate on the other suddenly make up for all that time they saw the other being frozen? It just doesn't work. Next let's go back to our train and light pulses, if the train is seen to shrink from the earth frame, then the distance of the meter shrinks so even though they are moving with the light pulse the stationary observer could expect their speed of light measure to agree. But now what if we send another pulse in the other direction??? Now the earth measures the expected rate, sure. But the train is travelling against the direction, this would cause them to expect to find the light to be, ahem, superluminal. So again we hop off the train and see the length of the train has contracted, this helped light travelling with the train attain it's expected speed, but now it is working against us! Clearly length contraction might be effective at fixing the speed of light in one direction, but it heaps up the problem on the other side. How can light speed possibly be corrected by something that only works with one half of the problem and makes the other side worse? You can't just turn length contraction off and on when and where it suits, if it exists it exists for both problems. Ok, so how about time dilation? Well I have already argued that time dilation without a discoverable preferred reference frame simply isn't possible, and time dilation with a discoverable preferred reference frame isn't SR, it is an aethericmodel. But let's just argue it anyway? So to the outside observer according to SR the time on the train should slow down, does this fix our measured light speed problem? Well if the train is moving with the light pulse direction, from the earth view the passage of time on the train has slowed, this means that their clock is moving slowly and so even though they are moving with the light which should make the light seem slow, the light might be measured to be the same speed since their clock are slow, and the length contraction on top of that. But if the light pulse is opposite the trains motion, they might expect to measure the light to be faster than C. So time dilation slows their clock down, so even less train clock time passes before light moves across the length contracted meter that separates the 2 light sensors. Seriously, how has this illusion lasted for so long when it only helps light travelling with the train/spaceship but compounds the problem for light moving the other direction? I can accept that these arguments will not persuade an intellectually dishonest establishment science. But can we agree that this is not a realistic model of the universe? And if it is not, what model could exist that agrees with all physical evidence besides an entrained aether? And if the aether is entrained, then can an electrodynamic experiment to prove or disprove this not be found? John