Re: The velocity of light going pass a moving train.

On 21 jun, 11:09, Dono <s...@xxxxxxxxxxx> wrote:

Since the physics tell us that, in both the frame of the train and the
frame of the observer in the track, both observers should see after
some time that the light reaches the ceiling mirror, then how that is
possible if, according to your explanation, the ground observer sees
the light direction going opposite (backwards) to the train movement.
That means that the light, seen from the ground, will totally miss the
mirror at the ceiling, since that mirror has moved to the right with
the rest of the train, while the light is moving towards the left (at
a 120 degrees angle if v=0.5c) according to your angle calculation.

Miguel Rios- Hide quoted text -

- Show quoted text -

At low v the angle theta_track = arccos(-v/c) differes very little
from pi/2, so, as I said earlier, the light, in the track frame, will
miss the mirror center by very little.

At high v , the situation changes, especially if the height of the car
is large and if the mirror is small. From the perspective of the track
frame, if the light is emitted as a laser beam, it will miss the
mirror.

- Mostrar texto de la cita -

I'm sorry but both observers (in the moving train and on the track)
are just looking what happens when the light (bunch of photons) goes
up into the mirror. So the fact that happens in the experiment is the
light hitting the mirror dead center (which is also what the train
observer sees). The observer on the track is observing the very same
event. The only odd things that may affect his vision of the
experiment are related to relativistics effects, including this
aberration thing. But at the end he will also see the light arriving
to the mirror, in the very same spot the in train observer sees it. We
can say that because of relativistics speed, both the train and the
mirror will be seen distorded from the track position, but the point
where the light hits the mirror is the same in both frames.
You are saying that even at low v, the track observer will see a
different event (or light show), that is "the light, in the track
frame, will miss the mirror center by very little", which is like
saying that, somehow, the very fact of observing the experiment
affects the result of the experiment.
Let's remember the experiment (also with trains moving at relativistic
speeds) in which two lightning strikes hit both ends of the train at
the same time, and we have also two observers one moving with the
train, the other on ground. The moving observer sees the strikes
hitting the train at different times (he is moving fast closing to the
front light wave while, at the same time, he is running away from the
back light wave), while the ground observer sees both strikes hitting
the train at the same time. This experiment is used to show the time
is not absolute, but the observation clearly do not affect in any way
the experiment result (the strikes hitting the train ends).

Miguel Rios

.

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