Otto Nomicus

I didn't dispute the obvious or say what you apparently think I said somewhere at some time, being that I'm not 5 years old. What I disputed was the idea that the clock moving horizontally meant that photons had to travel a longer path in the same amount of time. In Einstein's day, lasers hadn't been invented yet so apparently he could actually get people to believe that light emitted vertically could travel on a slant. What's YOUR excuse for believing it long after lasers were invented? Do you actually think that's logical, that a laser beam could change its direction of wave propagation from vertical to 40 degrees from vertical just because the emitter is moving sideways? You think that makes perfect sense huh? Interesting.

It's just the way things work, uniform motion is indistinguishable from no motion. Photons don't move sideways so that's the proof that uniform motion is equivalent to no motion. The way another frame may seem to you from your own frame is irrelevant. You can't clock the speed of light in another frame anyway, how could you? You can't even clock the one-way speed of light in your own frame, much less another one a distance from yours.

Valid point about it not originally being a laser, which wasn't invented until 1958, which may have been a prime reason why Einstein was susceptible to misconception, and why he could pass off his theory as plausible in those day, but since that time it was easy to see that his thought experiment couldn't work if it's a laser in the clock. Einstein's logic would be valid if photons were physical objects and the clock was analogous to a river. In that case the velocity would be the square root of the sum of the squares of the vertical velocity of the photons and the horizontal velocity of the clock/river. Can a moving clock apparatus continuously impart its horizontal velocity to photons after they leave the emitter and after they bounce off a mirror? Obviously not, because photons are not physical objects and therefore nothing physical can impart its velocity to it as it travels across it. If that were the case, shining a laser crosswise through moving water would deflect it in the direction of the moving water, and that has never been shown experimentally to occur. The only other thing that one could postulate could cause the photons to move horizontally with the clock is inertia, and obviously photons are not subject to inertia. Why would you and Einstein think photons would behave exactly the same as physical objects when they're not physical objects? There simply is no horizontal velocity being imparted on the photons because there is nothing known in physics that could cause it. So how is it that light can bounce up and down in a moving frame and not appear to bend in the rearward direction? Because a frame moving at uniform straight line velocity is exactly the same as the frame not moving at all, that's why. In fact, light doesn't even have velocity, it only has a rate of electric and magnetic field propagation, we just perceive that as velocity but it's not the same thing because no force is involved and no mass is involved, therefore no velocity is involved, it's a misconception. Maybe you just perceived it as a vertical beam moving 200 miles NE but in fact it was a series of photons being produced, each slightly NE of the previous. None of the photons actually moved 200 miles NE at all. You can't just have a self propagating light beam bouncing back and forth for 200 miles with the emitter turned off. Why does a beam not just keep bouncing back and forth for a long time after an emitter is turned off until it dissipates from energy loss? Nobody knows but it doesn't.

No, actually I would just keep my eyes focused on the moving light clock and see the beam going straight up and down like always. I wouldn't see any zig-zag. You could imagine a zig-zag but the light beam obviously wouldn't be propagating along the slanted lines, because the laser was never aimed on a slant and neither was the mirror. The cycle would take the exact same time to complete and there would be no reason to think you needed to imagine time going slower than normal on the train, and if you did, then light would be seen to be traveling at slower than normal speed, so why would you want to do that? Nobody here, including you, have explained how a laser beam directed vertically could have its beam emitted at an angle of about 40 degrees from vertical, in the case of the diagram I showed, and the mirror also magically adjust itself to the same angle. Why don't you do that now, I'm interested to hear the tale of the magic angled beam laser and the self adjusting mirror. Of course, the clock would have to catch up to the angled beam in time for it to hit the mirror. What if the clock stopped moving right after emitting the beam, the beam would miss the mirror, right? Or would it stop halfway through the trip to the mirror and adjust itself to going straight down? Yup, I'm very sad about that. Now why don't you also do as I invited Eise to do? Maybe one of you can provide a logical explanation.

Precisely, and that's why the cycle time of the moving clock does not require correcting using time dilation, it didn't take any longer just because a longer slanted path was imagined by Einstein. Thanks for agreeing that I am right, that's always nice. That was my entire point though, that the clock's cycle time stays the same regardless of its horizontal motion, thanks for agreeing.

You're actually showing one ray going straight down and a second ray going over at an angle, because it was emitted at an angle, it's two different light rays. You show it as circular waves but it could also be seen as rays coming out from the point in all directions, diverging from each other as they move farther from the source. A laser beam is not analogous to that at all, which is why it's a beam instead of looking like a light bulb. When you blow smoke in the area of a laser beam you see a thin pencil of light going directly straight out from the emitter. You're not showing a laser, you're showing essentially a mini-star. Now do an illustration with a laser beam emitted straight down and see what happens. Would the ball be moving faster than the speed of gravity in the vertical axis because the train is moving horizontally at the same time?

You did get it work out, and without complicated equations involving squares, well done. The only reservation I have is that the velocity of the clock along its horizontal path had to be distorted for it to work. I understand the logic behind it, that the light beam was perceived as completing a longer path than 1 m during the cycle and that was used as the basis for gauging the clock's velocity, assuming that the beam had traveled that path at normal light speed so it took a longer time, thus the clock must have traveled a shorter distance relative to the cycle time. What if the clock were traveling along a track set up in a lab of sufficient size and we could gauge its velocity along that track? We would find that it moved 0.866 m in the time the light took to complete its cycle, because the light beam really only moved the vertical height of the clock, not a slanted path. A laser beam doesn't propagate on a slant when directed vertically, because somebody would have noticed if it did. Why, then, would it be assumed that the beam had traveled a longer path simply because the clock moved horizontally at the same time? I don't think that's logically plausible. By that logic, if you dropped an object from a certain height and simultaneously threw another matching object horizontally then the one one dropped straight down would hit the ground before the horizontally thrown one, which is not actually the case. Do you consider the thrown object to have traveled a curved path to ground at a greater velocity than the dropped object traveled straight down, or do you just consider it to have traveled horizontally at a certain velocity at the same time as traveling vertically at the speed of gravity? It was two different velocity vectors, not one. The clock moving horizontally is a similar situation, the light waves moved straight down at 1 c while also moving horizontally at 0.866 c, or at least appearing to move horizontally, but it's velocity was not actually a combination of the two, which would mean it exceeded normal light speed and was therefore seen as requiring correction to bring it back down to normal, using velocity contraction and time dilation. There was never a need for correction because the photons had never traveled any farther than 0.5 m up and down vertically, totally a round trip of 1 m, at a velocity of 299,792,458 m/s. Now there's the question of whether the light waves/photons were actually inheriting the horizontal motion of the emitter after being emitted vertically. That would make it like a ball tossed vertically by a person on a moving train. What causes the ball to keep moving with the train after being tossed? The obvious answer is inertia. Does light possess inertia? How could it when inertia is a property of mass and light has no mass? So were the vertically propagating light waves really ever moving horizontally with the clock or was it an illusion? One thing is certain, the light was never propagating on a slanted path. It appears that the moving clock should have been considered as if it weren't moving at all, in which case, photons would not be required to possess inertia to explain the situation. The obvious conclusion is that, when observing a moving frame with a vertical light beam in it, you should consider the situation to be that you see the light clock exactly as you would if neither of you were moving, no time dilation involved whatsoever. If you see the situation that way then how could you see the situation differently if there were two beams in the moving frame, one vertical and one horizontal? You couldn't use time dilation for the horizontal beam and not have it also effect the vertical beam, which never required time correction at all. So how is time dilation a real thing? Maybe muons just decay more slowly when accelerated, how would you know that wasn't the real explanation for muons making it to the earth's surface? Their mass would supposedly be increased, that theory may be valid, and maybe their rate of decay is slowed in direct proportion to that mass increase. That would remove the most popular proof cited for time dilation and length contraction being valid.

Exactly. The conundrum is how to make the 1.323 m zig-zag path appear to take the same amount of time as the 1 m vertical path took when the clock was stationary. You obviously can't do it using the time dilation factor for 0.866 c, which is 2, so how do you do it?

It's based on light in the clock, which travels 1 m vertically in total round trip. If the clock itself moves horizontally 0.866 m during the time it takes for the light to make that round trip then obviously the clock apparatus must be moving horizontally at 0.866 c. You don't even need to know the actual value of c, just how far the apparatus moves in relation to how far the light beam moves, which is 0.866 to 1, thus velocity 0.866 c.

I'm not disputing that there's no length contraction. The time dilation factor for 0.866 c is 2. How does slowing time down to half speed resolve the path of the beam being longer than 1 m and therefore seeming to need to exceed normal c by about 32%? 32% os not 100% so how could a time dilation factor of 2 be appropriate?

Okay, thanks for that, but how would you get the equivalent of the zig-zag length being reduced to 1 m using relativity? I don't mean show me a bunch of confusing equations, I mean just logically how does a time dilation factor of 2 reduce 1.322875656 m to 1 m?

I drew a diagram to illustrate Einstein's moving light clock thought experiment but it doesn't seem to work out right with the time dilation factor for the velocity involved. The light clock is 0.5 m in height so the two-way light beam trip would be 1 m. The clock completes its up/down cycle in the time it takes for it to move to the right 0.866025403 m, which means the clock's velocity is 0.866025403 c. The time dilation factor for that velocity is 2. How do you get the zig-path down to 1 m, like it is inside the clock when it's not moving, by dividing it by 2? Even if I contract space and say that the clock's path is only 0.43301270189221932338186158537647 c, the time dilation factor for that velocity is 1.1094 while the length of the zig-zag would be 1.089724736 m. While it's close, it still doesn't work out exactly. Do I even need to contract the clock's path to half? I don't think I would have to but you tell me. I realized that I wouldn't need to contract the bottom line by a factor of 2 if the velocity wasn't even 0.866 c to start with, so that part is moot.