Down the relativistic rabbit-hole (Split from official news)

[Grench]

Grench let me just clarify that what you re saying is that there is an absolute refrence frame from which light moves at c relative to, and other refrence frames that move at some speed x relative to such frame see light travel at c+x in one direction and c-x in the oposite one.

Is this correct?

No. There is no such thing as c+x.

So, lets try this another way.

* = a star.
O1 = an object (planet, whatever) moving toward *
O2 = an object (planet, whatever) moving away from *


-----------------------------O1<
*
-----------------------------O2>

The star goes supernova at a point where the two are equidistant from the star.
The light from the supernova propagates outward by the Lorentz equation.
O1 moves toward the star.
O2 moves away from the star.

--------------|-------------O1<
* |
--------------|-----------------O2>

The light reaches 01 where it is 'seen' moving at c, prior to reaching 02, where it also is 'seen' moving at c. This is regardless of the velocity of 01 and 02. Relativity still holds true.
-------------------------|O1<
* |
-------------------------|---------O2>

You can spin 01 and 02 around the star (light source) to any angle you would like - including a straight line train car example. The progressing and regressing bodies will be in different positions, i.e. different distances from the light source by the time the light source can be detected by them.

Also of note, whatever is left of the start that went supernova in the above example would likely be moving as well. By the time O1 or O2 would observe it, those remains would potentially be in an entirely different point in space.

[doublepost=1527869113,1527867227][/doublepost]

not sure why you're thinking light has to travel infinitely fast for my perspective to work out. light travels at c in all reference frames. which is why the light hits both sides of the train simultaneously, in the reference frame of the train. (the walls aren't moving in the reference frame of the train.)

Just as I'm not sure why you seem to insist that placing walls around a system somehow makes it behave different from the rest of the observable universe.

The train example from your textbook is VERY specific to a central observer in the train and to the return time from light bouncing off the front and rear of the train arriving at the center at the same time - taking the same travel time - as in a non-moving reference. THAT is true. It is because the average distance traveled from center to end to center is static regardless of velocity. The faster it is going, the shorter one leg of light's journey gets and the longer the other leg gets. That is because of relativity - light has an absolute velocity and point of origin and propagates in a predictable way.

Declaring a 'system' does not magically exempt the points in it from those facts.

you think there's an absolute picture of what's happening, that there's only one "truth." (light hits both sides of the train at different times, watching the train go by. this is the case in the reference frame of the "earth" or "embankment" terminology used by Einstein.)

I am not arguing against this. From the embankment, this is correct as the net travel distance for light from source to walls to observer are different lengths.

but there's a second, equally valid "truth" -- that light hits both sides of the train at the same time, and this is true for observers in the train. (even with infinitely accurate clocks.)

Which is ONLY valid for a centered observer who is looking at the reflected light from the train walls progressing and regressing to and from the light source respectively and at a constant rate. Not observers, but observer.

There is a third truth that for whatever reason you are arguing against regardless of existence in nature. The third viewing case where the walls ARE the detection points and no reflection is considered.

Michelson--Morley was the best shot at proving there exists an "absolute velocity" (i.e., being able to keep a single "time" and understand things in an absolute context, but still "relative" to the aether). they failed, in a brilliant way. there is no sense of an absolute velocity; any such thinking goes backwards from relativity (in the sense that you're going back to Newton), and doesn't explain anything moving forwards from relativity (i.e. new phenomena).

it's like saying that phlogiston is really what makes fires burn, honestly.

Its a witch. Burn it. Clearly if a person considers cases that are an exception to the text books, they must be a herritic.

Pulling up references to 1877 experiments claiming that they set a gold standard is a bit much. They had no solid concept of the speed of light let alone clocks accurate enough to measure it over practical distances.

 

[Djoga'Ro]

I think, Grench is just trolling

 

[Kuro]

in your example O1 records light hitting it a Time1 and sees light hit O2 at Time1+x1, O2 records light hitting it at Time2 and sees light hit O1 at Time2-y1. If both broadcast the Time1 and Time2 to each other they would see that Time1=Time2.
An observer O3 traveling at a speed somewere in between O1 and O2 that meets them at the same time they meet in the same place, sees light hitting it at Time3 and light hit O1 at Time3-y2 and hit O2 at Time3+x2.

Time3 is equal to Time1 and Time2 that is equal to the distance between the meeting point and the supernova divided by c, and x2 < x1 and y2 < y1.

Note that in their own refrence frame none of the observers left the meeting point.

The closer the speed of O3 is to O1 the smaller the diference there is between x1 and x2 and y2 and 0, the same way that the closer the speed of O3 is to O2 the smaller the diference between y1 and y2 and x2 and 0.

In your example you have represented it from the point of view of the observer O3.

So please tell me how from this information would you infer any absolute refrence frame.

 

[ible]

it's the same for reflections or not. observers, traveling on the train, standing at the walls, will record the same time for when the light reaches them. (even with infinitely precise clocks, and a train traveling at 0.99c).

regarding michelson--morley -- those who don't learn from the past are doomed to repeat it...

here's a thought experiment for you. let's reverse the situation a bit.

consider now that the light comes from a lamp on the "embankment," and there are two walls on either side of the train station. suppose also, in the reference frame of people on the earth, people see the light reach the two walls at the same time (i.e. the walls are equidistant between the lamp), and that at that exact same time that the light hits the walls, the train is exactly midway between the walls. (that last point isn't too important, but helps keep things centered.) suppose the train is traveling at 0.1c.

in the reference frame of this train, the walls are both traveling at -0.1c. in this reference frame, the light will reach the far wall sooner than the near wall, because the near wall is traveling away from the light, and the far wall is traveling towards the light.

this is exactly the same situation as when the lamp is on the train, but reversed. no reference frame is privileged.